Microbial cellulases - Diversity & biotechnology with reference to mangrove environment: A review

Eco-friendly structures for sustainable mangrove restoration

Mangrove forests around the world are under significant pressure from climate change (e.g., rising sea levels), and human-related anthropogenic activities (e.g., coastal infrastructure development). Mangrove restoration projects have increased over the past decades but seedling and propagule survival rates are reportedly low, while many projects have failed. There exists a need to assess the effectiveness of sustainable and cost-effective eco-friendly structures (EFS) for advancing the success of mangrove restoration and planting activities. Herein, by EFS, we refer to the frameworks made of biodegradable materials that help overcome establishment bottlenecks and thereby boost seedling survival and growth rates. In this study, we explored the effectiveness of EFS in aiding mangrove restoration success by enhancing seedling establishment and survival and tree growth rates. Furthermore, we examine the steps involved and the challenges limiting EFS implementation in mangrove restoration projects. EFS installed in coastal areas trap sediment and may provide protection for newly planted mangrove seedlings and propagules by providing a stable anchorage and attenuating water flow and waves. Additionally, once plants are established, these biodegradable structures would decompose and add to the soil nutrients stock, thereby improving its fertility and supporting mangrove growth. We emphasize that in sites with favorable biophysical conditions for mangrove growth (hydrology, soil, topography, climate, among others), using EFS can improve mangrove restoration success by enhancing seedling establishment, survival and growth. Mangrove restoration success may have add-on benefits such as increasing the provision of related ecosystem services, blue carbon credit financing and overall coastal environmental sustainability. Given the novelness of this topic in the scientific literature, this article aims to stimulate active discussions, including anticipation of potential challenges (e.g., cost-effectiveness, ability to scale and field limitations in a range of biogeographic settings), for bringing in improvements and scalable adoption strategies to the mangrove restoration approaches under consideration.

Metagenomics and plant-microbe symbioses: Microbial community dynamics, functional roles in carbon sequestration, nitrogen transformation, sulfur and phosphorus mobilization for sustainable soil health

Biogeochemical cycles are fundamental processes that regulate the flow of essential elements such as carbon, nitrogen, and phosphorus, sustaining ecosystem productivity and global biogeochemical equilibrium. These cycles are intricately influenced by plant-microbe symbioses, which facilitate nutrient acquisition, organic matter decomposition, and the transformation of soil nutrients. Through mutualistic interactions, plants and microbes co-regulate nutrient availability and promote ecosystem resilience, especially under environmental stress. Metagenomics has emerged as a transformative tool for deciphering the complex microbial communities and functional genes driving these cycles. By enabling the high-throughput sequencing and annotation of microbial genomes, metagenomics provides unparalleled insights into the taxonomic diversity, metabolic potential, and functional pathways underlying microbial contributions to biogeochemical processes. Unlike previous reviews, this work integrates recent advancements in metagenomics with complementary omics approaches to provide a comprehensive perspective on how plant-microbe interactions modulate biogeochemical cycles at molecular, genetic, and ecosystem levels. By highlighting novel microbial processes and potential biotechnological applications, this review aims to guide future research in leveraging plant-microbe symbioses for sustainable agriculture, ecosystem restoration, and climate change mitigation.

Microbial Rumen proteome analysis suggests Firmicutes and Bacteroidetes as key producers of lignocellulolytic enzymes and carbohydrate-binding modules

Lignocellulosic biomass, rich in cellulose, hemicellulose, and lignin, offers a sustainable source for biofuels and and production of other materials such as polymers, paper, fabrics, bioplastics and biofertilizers. However, its complex structure hinders efficient conversion. Chemical, enzymatic, and microbial methods aim to unlock the trapped sugars and phenols. The rumen microbiome, a fascinating ecosystem within ruminant animals, holds particular promise. The Hungate 1000 project sequenced 410 microbial genomes from the rumen, enabling in silico screening for lignocellulolytic enzymes. This approach saves time and resources, supporting the development of sustainable bioconversion technologies aligned with the UN's 2030 agenda goals. Analysis of these 410 predicted proteomes revealed diverse carbohydrate-active enzymes (CAZymes) and carbohydrate-binding modules (CBMs) across various microorganisms. Notably, Firmicutes and Bacteroidetes dominated CAZyme and CBM production, suggesting collaborative efforts among different phyla during degradation. The presence of CBM50 and chitinases hints at the ability to utilize chitin from fungal cell walls. Interestingly, the absence of ligninolytic auxiliary activity enzymes reaffirms the rumen microbiome's incapability of directly degrading lignin. However, enzymes facilitating the loosening of the cell wall by cleaving lignin-hemicellulose linkages were identified. This suggests a strategy for making cellulose more accessible to hydrolytic enzymes. This study highlights the intricate relationship between rumen microbes, contributing necessary enzymes for plant cell wall deconstruction in this unique environment. Additionally, it underlines the power of in silico techniques for analyzing big data, paving the way for advancements in sustainable bioconversion.

Impact of straw returning on soil ecology and crop yield: A review

Several studies have demonstrated the effect of straw return on enhancing soil ecology, promoting sustainable agricultural practices, and cumulative effects on plant yield. Recent studies have focused on straw return methods and their impact on soil nutrient cycling and the overall physicochemical composition of the soil. Despite the substantial progress and successes, several research gaps in these studies require further investigations to harness the full potential of straw return. This review provides a thorough examination of straw diversity and decomposition mechanisms, the effects of straw on soil microorganisms, the interactions between cellulolytic nitrogen-fixing microbes and lignocellulose biomass, as well as nutrient mineralization, organic matter content, and their influence on plant growth and yield. This review also examined the effects of straw return on plant pathogens and its allelopathic impact on plant growth, highlighting research gaps to encourage further studies that could fully realize the potential benefits of straw return in agricultural fields for optimal plant growth.

Isolation and Characterization of a Promising Lignocellulolytic Enzyme Producer Pseudolagarobasidium acaciicola SL3-03 from Mangrove Soil in Thailand

Lignocellulolytic enzymes isolation from mangrove-derived organisms has many industrial advantages due to their efficiency in dealing with extreme and challenging conditions, such as high temperatures and salt concentrations. This study aimed to isolate fungal enzyme producers from mangrove soil in Thailand to produce lignocellulolytic enzymes (carboxymethyl cellulase: CMCase, xylanase, and laccase) and to characterize these enzymes to support industrial applications. Forty-eight fungi were isolated from the mangrove samples, and their enzyme-producing capabilities were assessed using primary and secondary screening methods. The findings revealed that Pseudolagarobasidium acaciicola SL3-03 emerged as a promising producer of lignocellulolytic enzymes. It exhibited the ability to produce 1.345 U/mL of CMCase, 1.293 U/mL of xylanase, and 43.126 U/mL of laccase. Furthermore, the enzymatic characteristics of P. acaciicola SL3-03 were analyzed. The CMCase exhibited optimal activity at 50 °C and pH 5.5, the xylanase at 50 °C and pH 4.8, and the laccase at 55 °C and pH 5. Besides, the CMCase and xylanase from P. acaciicola SL3-03 expressed high halotolerance abilities that could maintain activity and stability under high salt concentrations (149% activity at 5 M NaCl). Future studies may focus on structural analysis of the enzymes to further characterize and identify their specific types. The results suggest that mangrove soil harbors significant potential for discovering proficient lignocellulolytic enzyme producers with desirable characteristics, which can be advantageous for industrial applications.

Isolation and screening of wood-decaying fungi for lignocellulolytic enzyme production and bioremediation processes

The growing demand for novel enzyme producers to meet industrial and environmental needs has driven interest in lignocellulose-degrading fungi. In this study, lignocellulolytic enzyme production capabilities of environmental fungal isolates collected from boreal coniferous and nemoral summer green deciduous forests were investigated, using Congo Red, ABTS, and Azure B as indicators of cellulolytic and ligninolytic enzyme productions. Through qualitative and quantitative assays, the study aimed to identify promising species for lignocellulose-degrading enzyme secretion and assess their potential for biotechnological applications. Primary screening tests showed intensive enzyme secretion by certain isolates, particularly white rot fungi identified as Trametes pubescens and Cerrena unicolor. These fungi exhibited high efficiency in degrading Congo Red and Azure B. The isolates achieved up to a 93.30% decrease in Congo Red induced color intensity and over 78% decolorization of Azure B within 168 hours. Within 336 hours, these fungi reached nearly 99% removal of Congo Red and up to 99.79% decolorization of Azure B. Enzyme activity analysis confirmed the lignin-degrading capabilities of T. pubescens, which exhibited laccase activity exceeding 208 U/mL. Furthermore, Fomitopsis pinicola showed the highest cellulose-degrading potential among the studied fungi, achieving cellulase activity over 107 U/L during Congo Red decolorization. Previously undescribed enzyme-producing species, such as Peniophora cinerea, Phacidium subcorticalis, and Cladosporium pseudocladosporioides, also demonstrated promising lignocellulolytic enzyme production potential, achieving up to 98.65% and 99.80% decolorization of Congo Red and Azure B, respectively. The study demonstrates novel candidates for efficient lignocellulolytic enzyme production with broad biotechnological applications such as biomass conversion, wastewater treatment, textile dye and other complex chemical removal, and environmental remediation.

In Vitro Biological Activities of an Endophytic Fungus, Trichoderma sp. L2D2 Isolated from Anaphalis contorta

The endophytic fungus, Trichoderma sp. L2D2 was isolated from the medicinal plant Anaphalis contorta and has been assessed for extracellular enzyme production, plant growth promotion, antifungal, antibacterial, and antioxidant activities in vitro. The endophyte has been found to produce amylase, cellulose, and ammonia qualitatively. The antifungal activity was evaluated using Curvularia lunata, Fusarium oxysporum, Aspergillus niger, Aspergillus flavus, Sclerotium oryzae, Rhizoctonia solani, Alternaria brassicicola, Colletotrichum capsici, Ustilaginoidea virens, and Alternaria tenuissima by the dual culture method and showed strong antifungal activity with 100% inhibition against S. oryzae and C. capsici. For antibacterial activity, ethyl acetate extract of Trichoderma sp. L2D2 was tested against Bacillus subtilis, Staphylococcus aureus, Enterococcus faecalis, Salmonella typhi, Escherichia coli, and Shigella flexneri by the agar well diffusion method and the 96-well microplate method, and has shown the lowest MIC of 15.62 µg/ml against S. aureus and E. coli. The DPPH assay was used to examine the free radical scavenging activity of the crude extract of the endophytic fungus and showed good antioxidant activity with an IC50 value of 85.94 µg/ml.

Regulation of genes encoding polysaccharide-degrading enzymes in Penicillium

Penicillium fungi, including Penicillium oxalicum, can secrete a range of efficient plant-polysaccharide-degrading enzymes (PPDEs) that is very useful for sustainable bioproduction, using renewable plant biomass as feedstock. However, the low efficiency and high cost of PPDE production seriously hamper the industrialization of processes based on PPDEs. In Penicillium, the expression of PPDE genes is strictly regulated by a complex regulatory system and molecular breeding to modify this system is a promising way to improve fungal PPDE yields. In this mini-review, we present an update on recent research progress concerning PPDE distribution and function, the regulatory mechanism of PPDE biosynthesis, and molecular breeding to produce PPDE-hyperproducing Penicillium strains. This review will facilitate future development of fungal PPDE production through metabolic engineering and synthetic biology, thereby promoting PPDE industrial biorefinery applications. KEY POINTS: • This mini review summarizes PPDE distribution and function in Penicillium. • It updates progress on the regulatory mechanism of PPDE biosynthesis in Penicillium. • It updates progress on breeding of PPDE-hyperproducing Penicillium strains.

Optimized production and characterization of a thermostable cellulase from Streptomyces thermodiastaticus strain

A high cellulase-producing bacterial isolate TS4 was recovered from an Egyptian soil sample and identified using 16S rRNA gene sequencing as Streptomyces thermodiastaticus. One-factor-at-a-time (OFAT) preliminary studies were carried out to determine the key factors affecting cellulase production by S. thermodiastaticus and their optimum ranges. The initial pH of the medium, carboxymethyl cellulose (CMC), tryptone, and NaCl concentrations were further optimized using a response surface Central Composite design. Fermentation under optimized variables of initial pH 6.0, presence of CMC, tryptone, and NaCl at concentrations of 2%, 0.03%, and 0.12%, respectively, resulted in 3.24 fold increase in cellulase productivity (2023 U/L) as compared to that under basal conditions (625 U/L). Cellulase production was also improved with a 4 Kilogray (KGy) dosage of gamma radiation. In comparison to the wild-type strain under basal circumstances, S. thermodiastaticus produced 5.1 fold more cellulase after a combination of model-based optimization and gamma radiation mutation. Cellulase was partially purified using ammonium sulfate precipitation followed by dialysis. The resulting cellulase was 1.74 times purified and its specific activity was 4.21 U/mg. The molecular weight of cellulase is 63 kDa as indicated by SDS-PAGE and zymogram. Its maximum activity was achieved at 60 °C and pH 5.0. In addition, it showed outstanding thermo-tolerance as it could retain its full activity after a 12-h incubation at 90 °C.

Extraction and characterization of novel alternative cellulosic fiber for sustainable textiles from Aloe barbadensis Miller stems (agricultural waste)

Novel research has been conducted on Aloe vera, focusing on stems fiber (agricultural waste), for the extraction of cellulosic fiber, an area lacking prior scientific exploration. This fiber is being reported for the first time in the scientific community. Aloe barbadensis Miller variety was subjected to various cultivation methods, including the application of inorganic and organic fertilizers, along with the removal of lower leaves to promote stem growth. Stem fibers were extracted using the water retting method and subsequently analyzed. The moisture content was 55.35 % and 6.99 % ash content in the fibers. The bacteriostatic analysis of Aloe vera fibers was assessed against four bacterial strains, with both ethanol and water extracts showing varying degrees of inhibition zones. The UV-Visible spectrum exhibited a distinct λ max at 247 nm in ethanol, while FT-IR analysis provided characteristic peaks at 3759, 1590, 1750, 1663, 1250, 564, SEM images displayed the smooth surface morphology of the fibers, and X-ray diffraction analysis indicated a high degree of crystallinity (78.67 %), suggesting a well-structured and crystalline nature. Energy dispersive X-ray (EDX) analysis was conducted to determine the elemental composition of the fibers, revealing the presence of carbon, oxygen, calcium, and copper, with carbon being the predominant element in cellulose. These results showed promising properties suggesting potential applications in textile industry as an alternative sustainable natural cellulosic fiber.

Cellulolytic potential of mangrove bacteria Bacillus haynesii DS7010 and the effect of anthropogenic and environmental stressors on bacterial survivability and cellulose metabolism

Cellulose degrading bacterial diversity of Bhitarkanika mangrove ecosystem, India, was uncovered and the cellulose degradation mechanism in Bacillus haynesii DS7010 under the modifiers such as pH (pCO2), salinity and lead (Pb) was elucidated in the present study. The abundance of cellulose degrading heterotrophic bacteria was found to be higher in mangrove sediment than in water. The most potential strain, B. haynesii DS7010 showed the presence of endoglucanase, exoglucanase and β-glucosidase with the maximum degradation recorded at 48 h of incubation, with 1% substrate concentration at 41 °C incubation temperature. Two glycoside hydrolase genes, celA and celB were confirmed in this bacterium. 3D structure prediction of the translated CelA and CelB proteins showed maximum similarities with glycoside hydrolase 48 (GH48) and glycoside hydrolase 5 (GH5) respectively. Native PAGE followed by zymogram assay unveiled the presence of eight isoforms of cellulase ranged from 78 kDa to 245 kDa. Among the stressors, most adverse effect was observed under Pb stress at 1400 ppm concentration, followed by pH at pH 4. This was indicated by prolonged lag phase growth, higher reactive oxygen species (ROS) production, lower enzyme activity and downregulation of celA and celB gene expressions. Salinity augmented bacterial metabolism up to 3% NaCl concentration. Mangrove leaf litter degradation by B. haynesii DS7010 indicated a substantial reduction in cellulolytic potential of the bacterium in response to the synergistic effect of the stressors. Microcosm set up with the stressors exhibited 0.97% decrease in total carbon (C%) and 0.02% increase in total nitrogen (N%) after 35 d of degradation while under natural conditions, the reduction in C and the increase in N were 4.05% and 0.2%, respectively. The findings of the study suggest the cellulose degradation mechanism of a mangrove bacterium and its resilience to the future consequences of environmental pollution and climate change.

Enhancing soil amendment for salt stress using pretreated rice straw and cellulolytic fungi

Rice straw breakdown is sluggish, which makes agricultural waste management difficult, however pretreatment procedures and cellulolytic fungi can address this issue. Through ITS sequencing, Chaetomium globosum C1, Aspergillus sp. F2, and Ascomycota sp. SM2 were identified from diverse sources. Ascomycota sp. SM2 exhibited the highest carboxymethyl cellulase (CMCase) activity (0.86 IU/mL) and filter-paper cellulase (FPase) activity (1.054 FPU/mL), while Aspergillus sp. F2 showed the highest CMCase activity (0.185 IU/mL) after various pretreatments of rice straw. These fungi thrived across a wide pH range, with Ascomycota sp. SM2 from pH 4 to 9, Aspergillus sp. F2, and Chaetomium globosum C1 thriving in alkaline conditions (pH 9). FTIR spectroscopy revealed significant structural changes in rice straw after enzymatic hydrolysis and solid-state fermentation, indicating lignin, cellulose, and hemicellulose degradation. Soil amendments with pretreated rice straw, cow manure, biochar, and these fungi increased root growth and soil nutrient availability, even under severe salt stress (up to 9.3 dS/m). The study emphasizes the need for a better understanding of Ascomycota sp. degradation capabilities and proposes that using cellulolytic fungus and pretreatment rice straw into soil amendments could mitigate salt-related difficulties and improve nutrient availability in salty soils.

Isolation and characterization of cellulase producing bacteria from forest, cow dung, Dashen brewery and agro-industrial waste

The continuous accumulation of waste, particularly from industries, often ends up in landfills. However, this waste can be transformed into a valuable resource through innovative methods. This process not only reduces environmental pollution but also generates additional useful products. This study aims to screen novel high-efficiency cellulose-degrading bacteria from cow dung, forest soil, brewery waste, and agro-industrial waste in the Debre Berhan area for the treatment of cellulose-rich agricultural waste. The serial dilution and pour plate method was used to screen for cellulolytic bacteria and further characterized using morphological and biochemical methods. From eleven isolates cow dung 1 (CD1), cow dung 6 (CD6) and cow dung (CD3) which produced the largest cellulolytic index (3.1, 2.9 and 2.87) were selected. Samples from forest soil, and spent grain didn't form a zone of clearance, and effluent treatment and industrial waste (IW9) shows the smallest cellulolytic index. Three potential isolates were then tested for cellulolytic activity, with cow dung 1 (CD1) displaying promising cellulase activity. These bacterial isolates were then identified as Bacillus species, which were isolated from cow dung 1 (CD1) with maximum cellulase production. Cow dung waste is a rich source of cellulase-producing bacteria, which can be valuable and innovative enzymes for converting lignocellulosic waste.

Current perspective in research and industrial applications of microbial cellulases

The natural interactions between various bacteria, fungi, and other cellulolytic microorganisms destroy lignocellulosic polymers. The efficacy of this process is determined by the combined action of three main enzymes: endoglucanases, exo-glucanases, and β-glucosidase. The enzyme attacks the polymeric structure's β-1,4-linkages during the cellulose breakdown reaction. This mechanism is crucial for the environment as it recycles cellulose in the biosphere. However, there are problems with enzymatic cellulose breakdown, including complex cellulase structure, insufficient degradation efficacy, high production costs, and post-translational alterations, many of which are closely related to certain unidentified cellulase properties. These issues impede the practical use of cellulases. A developing area of research is the application of this similar paradigm for industrial objectives. Cellulase enzyme exhibits greater promise in many critical industries, including biofuel manufacture, textile smoothing and finishing, paper and pulp manufacturing, and farming. However, the study on cellulolytic enzymes must move forward in various directions, including increasing the activity of cellulase as well as designing peptides to give biocatalysts their desired attributes. This manuscript includes an overview of current research on different sources of cellulases, their production, and biochemical characterization.

Comparative genomics reveals insight into the phylogeny and habitat adaptation of novel Amycolatopsis species, an endophytic actinomycete associated with scab lesions on potato tubers

A novel endophytic actinomycete, strain MEP2-6T, was isolated from scab tissues of potato tubers collected from Mae Fag Mai Sub-district, San Sai District, Chiang Mai Province, Thailand. Strain MEP2-6T is a gram-positive filamentous bacteria characterized by meso-diaminopimelic acid in cell wall peptidoglycan and arabinose, galactose, glucose, and ribose in whole-cell hydrolysates. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and hydroxy-phosphatidylethanolamine were the major phospholipids, of which MK-9(H6) was the predominant menaquinone, whereas iso-C16:0 and iso-C15:0 were the major cellular fatty acids. The genome of the strain was 10,277,369 bp in size with a G + C content of 71.7%. The 16S rRNA gene phylogenetic and core phylogenomic analyses revealed that strain MEP2-6T was closely related to Amycolatopsis lexingtonensis NRRL B-24131T (99.4%), A. pretoriensis DSM 44654T (99.3%), and A. eburnea GLM-1T (98.9%). Notably, strain MEP2-6T displayed 91.7%, 91.8%, and 87% ANIb and 49%, 48.8%, and 35.4% dDDH to A. lexingtonensis DSM 44653T (=NRRL B-24131T), A. eburnea GLM-1T, and A. pretoriensis DSM 44654T, respectively. Based on phenotypic, chemotaxonomic, and genomic data, strain MEP2-6T could be officially assigned to a novel species within the genus Amycolatopsis, for which the name Amycolatopsis solani sp. nov. has been proposed. The type of strain is MEP2-6T (=JCM 36309T = TBRC 17632T = NBRC 116395T). Amycolatopsis solani MEP2-6T was strongly proven to be a non-phytopathogen of potato scab disease because stunting of seedlings and necrotic lesions on potato tuber slices were not observed, and there were no core biosynthetic genes associated with the BGCs of phytotoxin-inducing scab lesions. Furthermore, comparative genomics can provide a better understanding of the genetic mechanisms that enable A. solani MEP2-6T to adapt to the plant endosphere. Importantly, the strain smBGCs accommodated 33 smBGCs encoded for several bioactive compounds, which could be beneficially applied in the fields of agriculture and medicine. Consequently, strain MEP2-6T is a promising candidate as a novel biocontrol agent and antibiotic producer.

An overview on the current status and future prospects in Aspergillus cellulase production

Cellulase is a new research point besides glucoamylase, amylase, and protease in the enzyme industry. Cellulase can decompose lignocellulosic biomass into small-molecule sugars, which facilitates microbial utilization; thus, it has a vast market potential in the field of feed, food, energy, and chemistry. The Aspergillus was the first strain used in cellulase preparation because of its safety and non-toxicity, strong growth ability, and high enzyme yield. This review provides the latest research and advances on preparing cellulase from Aspergillus. The metabolic mechanisms of cellulase secretion by Aspergillus, the selection of fermentation substrates, the comparison of the fermentation modes, and the effect of fermentation conditions have been discussed in this review. Also, the subsequent separation and purification techniques of Aspergillus cellulase, including salting out, organic solvent precipitation, ultrafiltration, and chromatography, have been declared. Further, bottlenecks in Aspergillus cellulase preparation and corresponding feasible approaches, such as genetic engineering, mixed culture, and cellulase immobilization, have also been proposed in this review. This paper provides theoretical support for the efficient production and application of Aspergillus cellulase.

Influence of Salinity on the Extracellular Enzymatic Activities of Marine Pelagic Fungi

Even though fungi are ubiquitous in the biosphere, the ecological knowledge of marine fungi remains rather rudimentary. Also, little is known about their tolerance to salinity and how it influences their activities. Extracellular enzymatic activities (EEAs) are widely used to determine heterotrophic microbes' enzymatic capabilities and substrate preferences. Five marine fungal species belonging to the most abundant pelagic phyla (Ascomycota and Basidiomycota) were grown under non-saline and saline conditions (0 g/L and 35 g/L, respectively). Due to their sensitivity and specificity, fluorogenic substrate analogues were used to determine hydrolytic activity on carbohydrates (β-glucosidase, β-xylosidase, and N-acetyl-β-D-glucosaminidase); peptides (leucine aminopeptidase and trypsin); lipids (lipase); organic phosphorus (alkaline phosphatase), and sulfur compounds (sulfatase). Afterwards, kinetic parameters such as maximum velocity (Vmax) and half-saturation constant (Km) were calculated. All fungal species investigated cleaved these substrates, but some species were more efficient than others. Moreover, most enzymatic activities were reduced in the saline medium, with some exceptions like sulfatase. In non-saline conditions, the average Vmax ranged between 208.5 to 0.02 μmol/g biomass/h, and in saline conditions, 88.4 to 0.02 μmol/g biomass/h. The average Km ranged between 1553.2 and 0.02 μM with no clear influence of salinity. Taken together, our results highlight a potential tolerance of marine fungi to freshwater conditions and indicate that changes in salinity (due to freshwater input or evaporation) might impact their enzymatic activities spectrum and, therefore, their contribution to the oceanic elemental cycles.

Enzymatic pretreatment for cellulose nanofiber production: Understanding morphological changes and predicting reducing sugar concentration

Enzymatic pretreatment plays a crucial role in producing cellulose nanofibers (CNFs) before fibrillation. While previous studies have explored how treatment severity affects CNF characteristics, there remains a lack of suitable parameters to monitor real-time enzymatic processes and fully comprehend the link between enzymatic action, fibrillation, and CNF properties. This study focuses on evaluating the impact of enzyme charge (using a monocomponent endoglucanase) and treatment time on cellulose fiber morphology and reducing sugar generation. For the first time, a random forest (RF) model is developed to predict reducing sugar concentration based on easily measurable process conditions (e.g., stirrer power consumption) and fiber/suspension characteristics like fines content and apparent viscosity. Polarized light optical microscopy was found to be a suitable technique to evaluate the morphological changes that fibers experience during enzymatic pretreatment. The research also revealed that endoglucanases initially induce surface fibrillation, releasing fine fibers into the suspension, followed by fiber swelling and shortening. Furthermore, the effect of enzymatic pretreatment on resulting CNF characteristics was studied at two fibrillation intensities, indicating that a high enzyme charge and short treatment times (e.g., 90 min) are sufficient to produce CNFs with a nanofibrillation yield of 19-23 % and a cationic demand ranging from 220 to 275 μeq/g. This work introduces a well-modeled enzymatic pretreatment process, unlocking its potential and reducing uncertainties for future upscaling endeavors.

Mangrove-associated endomycota: diversity and functional significance as a source of novel drug leads

Endophytic fungi are known for their unprecedented ability to produce novel lead compounds of clinical and pharmaceutical importance. This review focuses on the unexplored fungal diversity associated with mangroves, emphasizing their biodiversity, distribution, and methodological approaches targeting isolation, and identification. Also highlights the bioactive compounds reported from the mangrove fungal endophytes. The compounds are categorized according to their reported biological activities including antimicrobial, antioxidant and cytotoxic property. In addition, protein kinase, α-glucosidase, acetylcholinesterase, tyrosinase inhibition, antiangiogenic, DNA-binding affinity, and calcium/potassium channel blocking activity are also reported. Exploration of these endophytes as a source of pharmacologically important compounds will be highly promising in the wake of emerging antibiotic resistance among pathogens. Thus, the aim of this review is to present a detailed report of mangrove derived endophytic fungi and to open an avenue for researchers to discover the possibilities of exploring these hidden mycota in developing novel drug leads.

Systematic bioprospection for cellulolytic actinomycetes in the Chihuahuan Desert: isolation and enzymatic profiling

The quest for microbial cellulases has intensified as a response to global challenges in biofuel production. The efficient deconstruction of lignocellulosic biomass holds promise for generating valuable products in various industries such as food, textile, and detergents. This article presents a systematic bioprospection aimed at isolating actinomycetes with exceptional cellulose deconstruction capabilities. Our methodology explored the biodiverse oligotrophic region of Cuatro Cienegas, Coahuila, within the Chihuahuan Desert. Among the evaluated actinomycetes collection, 78% exhibited cellulolytic activity. Through a meticulous screening process based on enzymatic index evaluation, we identified a highly cellulolytic Streptomyces strain for further investigation. Submerged fermentation of this strain revealed an endoglucanase enzymatic activity of 149 U/mg. Genomic analysis of strain Streptomyces sp. STCH565-A revealed unique configurations of carbohydrate-active enzyme (CAZyme) genes, underscoring its potential for lignocellulosic bioconversion applications. These findings not only highlight the significance of the Chihuahuan Desert as a rich source of cellulolytic microorganisms but also offer insights into the systematic exploration and selection of high-performing cellulolytic microorganisms for application in diverse environmental contexts. In conclusion, our bioprospecting study lays a foundation for harnessing the cellulolytic potential of actinomycetes from the Chihuahuan Desert, with implications for advancing cellulose deconstruction processes in various industries. The findings can serve as a blueprint for future bioprospecting efforts in different regions, facilitating the targeted discovery of microorganisms with exceptional cellulosic deconstruction capabilities.

The Good, the Bad, and the Useable Microbes within the Common Alder (Alnus glutinosa) Microbiome-Potential Bio-Agents to Combat Alder Dieback

Common Alder (Alnus glutinosa (L.) Gaertn.) is a tree species native to Ireland and Europe with high economic and ecological importance. The presence of Alder has many benefits including the ability to adapt to multiple climate types, as well as aiding in ecosystem restoration due to its colonization capabilities within disturbed soils. However, Alder is susceptible to infection of the root rot pathogen Phytophthora alni, amongst other pathogens associated with this tree species. P. alni has become an issue within the forestry sector as it continues to spread across Europe, infecting Alder plantations, thus affecting their growth and survival and altering ecosystem dynamics. Beneficial microbiota and biocontrol agents play a crucial role in maintaining the health and resilience of plants. Studies have shown that beneficial microbes promote plant growth as well as aid in the protection against pathogens and abiotic stress. Understanding the interactions between A. glutinosa and its microbiota, both beneficial and pathogenic, is essential for developing integrated management strategies to mitigate the impact of P. alni and maintain the health of Alder trees. This review is focused on collating the relevant literature associated with Alder, current threats to the species, what is known about its microbial composition, and Common Alder-microbe interactions that have been observed worldwide to date. It also summarizes the beneficial fungi, bacteria, and biocontrol agents, underpinning genetic mechanisms and secondary metabolites identified within the forestry sector in relation to the Alder tree species. In addition, biocontrol mechanisms and microbiome-assisted breeding as well as gaps within research that require further attention are discussed.

Draft genome sequence of Hahella sp. CR1 and its ability in producing cellulases for saccharifying agricultural biomass

Hahella is a genus that has not been well-studied, with only two identified species. The potential of this genus to produce cellulases is yet to be fully explored. The present study isolated Hahella sp. CR1 from mangrove soil in Tanjung Piai National Park, Malaysia, and performed whole genome sequencing (WGS) using NovaSeq 6000. The final assembled genome consists of 62 contigs, 7,106,771 bp, a GC ratio of 53.5%, and encoded for 6,397 genes. The CR1 strain exhibited the highest similarity with Hahella sp. HN01 compared to other available genomes, where the ANI, dDDH, AAI, and POCP were 97.04%, 75.2%, 97.95%, and 91.0%, respectively. In addition, the CAZymes analysis identified 88 GTs, 54 GHs, 11 CEs, 7 AAs, 2 PLs, and 48 CBMs in the genome of strain CR1. Among these proteins, 11 are related to cellulose degradation. The cellulases produced from strain CR1 were characterized and demonstrated optimal activity at 60 ℃, pH 7.0, and 15% (w/v) sodium chloride. The enzyme was activated by K+, Fe2+, Mg2+, Co2+, and Tween 40. Furthermore, cellulases from strain CR1 improved the saccharification efficiency of a commercial cellulase blend on the tested agricultural wastes, including empty fruit bunch, coconut husk, and sugarcane bagasse. This study provides new insights into the cellulases produced by strain CR1 and their potential to be used in lignocellulosic biomass pre-treatment.

Eight Up-Coming Biotech Tools to Combat Climate Crisis

Biotechnology has a high potential to substantially contribute to a low-carbon society. Several green processes are already well established, utilizing the unique capacity of living cells or their instruments. Beyond that, the authors believe that there are new biotechnological procedures in the pipeline which have the momentum to add to this ongoing change in our economy. Eight promising biotechnology tools were selected by the authors as potentially impactful game changers: (i) the Wood-Ljungdahl pathway, (ii) carbonic anhydrase, (iii) cutinase, (iv) methanogens, (v) electro-microbiology, (vi) hydrogenase, (vii) cellulosome and, (viii) nitrogenase. Some of them are fairly new and are explored predominantly in science labs. Others have been around for decades, however, with new scientific groundwork that may rigorously expand their roles. In the current paper, the authors summarize the latest state of research on these eight selected tools and the status of their practical implementation. We bring forward our arguments on why we consider these processes real game changers.

The ecological effect of large-scale coastal natural and cultivated seaweed litter decay processes: An overview and perspective

Seaweeds are important components of marine ecosystems and can form a large biomass in a few months. The decomposition of seaweed litter provides energy and material for primary producers and consumers and is an important link between material circulation and energy flow in the ecosystem. However, during the growth process, part of the seaweed is deposited on the sediment surface in the form of litter. Under the joint action of the environment and organisms, elements enriched in seaweed can be released back into the environment in a short time, causing pollution problems. The cultivation yield of seaweed worldwide reached 34.7 million tons in 2019, but the litter produced during the growth and harvest process has become a vital bottleneck that restricts the further improvement of production and sustainable development of the seaweed cultivation industry. Seaweed outbreaks worldwide occur frequently, producing a mass of litter and resulting in environmental pollution on coasts and economic losses, which have negative effects on coastal ecosystems. The objective of this review is to discuss the decomposition process and ecological environmental effects of seaweed litter from the aspects of the research progress on seaweed litter; the impact of seaweed litter on the environment; and its interaction with organisms. Understanding the decomposition process and environmental impact of seaweed litter can provide theoretical support for coastal environmental protection, seaweed resource conservation and sustainable development of the seaweed cultivation industry worldwide. This review suggests that in the process of large-scale seaweed cultivation and seaweed outbreaks, ageing or falling litter should be cleared in a timely manner, mature seaweed should be harvested in stages, and dried seaweed produced after harvest and washed up on shore should be handled properly to ensure the benefits of environmental protection provided by seaweed growth and sustainable seaweed resource development.

Synthesis of methylcellulose-polyvinyl alcohol composite, biopolymer film and thermostable enzymes from sugarcane bagasse

Agro-industrial wastes and by-products are the natural and abundant resources of biomaterials to obtain various value-added items such as biopolymer films, bio-composites and enzymes. This study presents a way to fractionate and to convert an agro-industrial residue, sugarcane bagasse (SB), into useful materials with potential applications. Initially cellulose was extracted from SB which was then converted into methylcellulose. The synthesized methylcellulose was characterized by scanning electron microscopy and FTIR. Biopolymer film was prepared by using methylcellulose, polyvinyl alcohol (PVA), glutaraldehyde, starch and glycerol. The biopolymer was characterized to exhibit 16.30 MPa tensile strength, 0.05 g/m² h of water vapor transmission rate, 366 % of water absorption to its original weight after 115 min of immersion, 59.08 % water solubility, 99.05 % moisture retention capability and 6.01 % of moisture absorption after 144 h. Furthermore, in vitro studies on absorption and dissolution of model drug by biopolymer showed 2.04 and 104.59 % of swelling ratio and equilibrium water content, respectively. Biocompatibility of the biopolymer was checked by using gelatin media and it was observed that swelling ratio was higher in initial 20 min of contact. The extracted hemicellulose and pectin from SB were fermented by a thermophilic bacterial strain, Neobacillus sedimentimangrovi UE25 that yielded 12.52 and 6.4 IU mL^-1 of xylanase and pectinase, respectively. These industrially important enzymes further augmented the utility of SB in this study. Therefore, this study emphasizes the possibility for industrial application of SB to form various products.

The Impact of Microorganisms on the Performance of Linseed Oil and Tung Tree Oil Impregnated Composites Made of Hemp Shives and Corn Starch

In this study, the performance characteristics of hemp shives impregnated with linseed oil and tung tree oil (HS)- and corn starch (CS)-based biocomposites containing flame retardants were evaluated before and after treatment with the mixture of bacterium Pseudomonas putida and fungus Rhizopus oryzae. Enzymatic activities and physical-mechanical properties such as water absorption, thickness swelling, compressive strength, and thermal conductivity were tested to evaluate the suitability of selected composites for thermal insulation purposes. In addition, electron microscopy was used to investigate the impact of microorganisms on the microstructure of the material. It was determined that the type of oil used for impregnation significantly affects the properties of biocomposites after 6 months of incubation with mixture of bacterium P. putida and fungus Rh. oryzae. Biocomposites impregnated with linseed oil and after treatment with a mixture of microorganisms had cellulase activity of 25 U/mL, endo β-1-4-glucanase activity of 26 U/mL, lipase activity of 101 U/mL, only a 10% decrease in compressive strength, 50% higher short-term water absorption, unchanged swelling in thickness, and slightly decreased thermal conductivity compared to control biocomposites. At the same time, biocomposites with tung tree oil had a much more pronounced deterioration of the properties tested, cellulase activity of 28 U/mL, endo β-1-4-glucanase activity of 37 U/mL, lipase activity of 91 U/mL, two times lower compressive strength and two times higher short-term water absorption, 2.5 times greater thickness swelling, and a slightly increased thermal conductivity. We conclude that linseed oil provides better protection against the action of microorganisms compared to impregnation with tung tree oil.

Efficient degradation of rice straw through a novel psychrotolerant Bacillus cereus at low temperature

BACKGROUND

Rice straw (RS) is one of the largest sources of lignocellulosic, which is an abundant raw material for biofuels and chemicals. However, the natural degradation of RS under a low temperature environment is the biggest obstacle to returning straw to the field.

RESULTS

In the present study, one bacillus strain W118 was isolated. Strain W118 was identified as Bacillus cereus through morphological and physiological characterization and 16S rDNA sequencing. The optimum growth temperature and pH of strain W118 were 20 °C and 6.5, respectively. Simultaneously, it was found that the strain W118 grew well at low temperature, even at a temperature of 4 °C (OD₆₀₀  = 1.40 ± 0.01). The decrease of various compositions of RS after the fermentation process at a temperature of 20 °C and 4 °C for 14 days was 27.00 ± 0.02% and 23.70 ± 0.04%, respectively. The composition of RS decreased to 50.71 ± 0.02% after being fermented at 4 °C for 25 days. The results of scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction of RS showed that the compositions of RS were significant decreased.

CONCLUSION

This test suggests that the strain W118 is efficient for degrading RS at low temperature, which has great application potential for straw degradation in a low temperature area. © 2022 Society of Chemical Industry.

Genomic Analysis to Elucidate the Lignocellulose Degrading Capability of a New Halophile Robertkochia solimangrovi

Robertkochia solimangrovi is a proposed marine bacterium isolated from mangrove soil. So far, the study of this bacterium is limited to taxonomy only. In this report, we performed a genomic analysis of R. solimangrovi that revealed its lignocellulose degrading ability. Genome mining of R. solimangrovi revealed a total of 87 lignocellulose degrading enzymes. These enzymes include cellulases (GH3, GH5, GH9 and GH30), xylanases (GH5, GH10, GH43, GH51, GH67, and GH115), mannanases (GH2, GH26, GH27 and GH113) and xyloglucanases (GH2, GH5, GH16, GH29, GH31 and GH95). Most of the lignocellulolytic enzymes encoded in R. solimangrovi were absent in the genome of Robertkochia marina, the closest member from the same genus. Furthermore, current work also demonstrated the ability of R. solimangrovi to produce lignocellulolytic enzymes to deconstruct oil palm empty fruit bunch (EFB), a lignocellulosic waste found abundantly in palm oil industry. The metabolic pathway taken by R. solimangrovi to transport and process the reducing sugars after the action of lignocellulolytic enzymes on EFB was also inferred based on genomic data. Collectively, genomic analysis coupled with experimental studies elucidated R. solimangrovi to serve as a promising candidate in seawater based-biorefinery industry.

Novel biosynthesis of tellurium nanoparticles and investigation of their activity against common pathogenic bacteria

Objectives

Tellurium has received substantial attention for its remarkable properties. This study performed in vitro and in vivo testing of the antibacterial action of tellurium nanoparticles biosynthesized in actinomycetes against methicillin-resistant Staphylococcus aureus (MRSA), a common blood bacterial pathogen.

Methods

Nine actinomycete isolates were tested for their potential to reduce potassium tellurite (K₂TeO₃) and form tellurium nanoparticles (TeNPs). The most efficient actinomycete isolate in producing Tellerium nanoparticles was identified through molecular protocols. The generated TeNPs were characterized using UV, TEM, EDX, XRD and FTIR. The bacterial species implicated in bloodstream infections were detected at El Hussein Hospital. Bacterial identification and antibiotic susceptibility testing were performed using Vitek 2. An animal infection model was used to test the efficacy of the produced TeNPs against the most commonly isolated methicillin-resistant S. aureus using survival assays, colony counting, cytokine assessment and biochemical testing.

Results

The most efficient actinomycete isolate was identified as Streptomyces graminisoli and given the accession number (OL773539). The mean particle size of the produced TeNPs was 21.4 nm, and rods and rosette forms were observed. Methicillin-resistant S. aureus (MRSA) was the main bacterium (60%) causing blood stream infections, and was followed by Escherichia coli (25%) and Klebsiella pneumoniae (15%). The produced TeNPs were tested against MRSA, the bacterium most frequently isolated from blood, and showed a promising action inhibition zone of 24 ± 0.7 mm and an MIC of 50 μg/ml. An animal infection model indicated the promise of TeNPs alone or in combination with standard drugs to combat MRSA in a rat intravenous infection model.

Conclusion

TeNPs combined with vancomycin have successive impact to combat bacteremia for further verification of results.

A Novel Bacillus safensis-Based Formulation along with Mycorrhiza Inoculation for Controlling Alternaria alternata and Simultaneously Improving Growth, Nutrient Uptake, and Steviol Glycosides in Stevia rebaudiana under Field Conditions

The excess use of chemicals by farmers in the agroecosystems degrades soil quality, disturbs soil ecology, and increases soil salinity and health hazards in humans. Stevia rebaudiana is an important medicinal and aromatic crop whose leaves contain steviol glycosides (SGs). The Bacillus safensis NAIMCC-B-02323 strain STJP from the rhizosphere of S. rebaudiana producing salicylic acid (16.80 µg/mL), chitinase (75.58 U/mL), β-1,3-glucanase (220.36 U/mL), and cellulase (170 U/mL) was taken as a plant growth-promoting rhizobacteria (PGPR). The cell-free supernatant (CFS) from strain STJP showed significant biocontrol activity against Alternaria alternata (80%), suggesting the protective role of extracellular metabolite(s) against phytopathogens. Paneer whey-based bioformulation (P-WBF) was developed to exploit B. safensis STJP to enhance the growth, nutrient uptake, soil properties, stevioside content, and SGs biosynthesis in S. rebaudiana under an A. alternata-infested field. The combined treatment of P-WBF and mycorrhiza (Glomus fasciculatum ABTEC) significantly enhanced plant growth parameters after 90 days, in comparison with control. The symbiotic action (P-WBF and mycorrhiza) displayed much better results in terms of chlorophyll a and b (improved by 132.85% and 39.80%, respectively), protein (by 278.75%), flavonoid (by 86.99%), carbohydrate (by 103.84%), antioxidant (by 75.11%), and stevioside (by 120.62%) contents in plants as compared to the untreated set. Further, the augmentation of potassium (by 132.39%), phosphorous (by 94.22%), and zinc (by 111.11%) uptake in plant tissues and soil was also observed by the application of P-WBF and mycorrhiza. The expression of UGT74G1 and UGT85C2 genes related to SG biosynthesis was upregulated (2.7- and 3.2-fold, respectively) in plants treated with P-WBF and mycorrhiza as further confirmed by the accumulation of SGs. The results suggest that the application of P-WBF and mycorrhiza not only provides an ecofriendly and sustainable solution to improve stevioside content in S. rebaudiana by a nutrient-linked mechanism but also paves the way to enhanced production of stevioside.

Application of Principal Component Analysis (PCA) to the Evaluation and Screening of Multiactivity Fungi

Continued innovation in screening methodologies remains important for the discovery of high-quality multiactive fungi, which have been of great significance to the development of new drugs. Mangrove-derived fungi, which are well recognized as prolific sources of natural products, are worth sustained attention and further study. In this study, 118 fungi, which mainly included Aspergillus spp. (34.62%) and Penicillium spp. (15.38%), were isolated from the mangrove ecosystem of the Maowei Sea, and 83.1% of the cultured fungi showed at least one bioactivity in four antibacterial and three antioxidant assays. To accurately evaluate the fungal bioactivities, the fungi with multiple bioactivities were successfully evaluated and screened by principal component analysis (PCA), and this analysis provided a dataset for comparing and selecting multibioactive fungi. Among the 118 mangrove-derived fungi tested in this study, Aspergillus spp. showed the best comprehensive activity. Fungi such as A. clavatonanicus, A. flavipes and A. citrinoterreus, which exhibited high comprehensive bioactivity as determined by the PCA, have great potential in the exploitation of natural products and the development of new drugs. This study demonstrated the first use of PCA as a time-saving, scientific method with a strong ability to evaluate and screen multiactive fungi, which indicated that this method can affect the discovery and development of new drugs.

Microbially-derived cocktail of carbohydrases as an anti-biofouling agents: a 'green approach'

Enzymes, also known as biocatalysts, display vital properties like high substrate specificity, an eco-friendly nature, low energy inputs, and cost-effectiveness. Among their numerous known applications, enzymes that can target biofilms or their components are increasingly being investigated for their anti-biofouling action, particularly in healthcare, food manufacturing units and environmental applications. Enzymes can target biofilms at different levels like during the attachment of microorganisms, formation of exopolymeric substances (EPS), and their disruption thereafter. In this regard, a consortium of carbohydrases that can target heterogeneous polysaccharides present in the EPS matrix may provide an effective alternative to conventional chemical anti-biofouling methods. Further, for complete annihilation of biofilms, enzymes can be used alone or in conjunction with other antimicrobial agents. Enzymes hold the promise to replace the conventional methods with greener, more economical, and more efficient alternatives. The present article explores the potential and future perspectives of using carbohydrases as effective anti-biofilm agents.

Microbial diversity and ecological interactions of microorganisms in the mangrove ecosystem: Threats, vulnerability, and adaptations

Mangroves are among the world's most productive ecosystems and a part of the "blue carbon" sink. They act as a connection between the terrestrial and marine ecosystems, providing habitat to countless organisms. Among these, microorganisms (e.g., bacteria, archaea, fungi, phytoplankton, and protozoa) play a crucial role in this ecosystem. Microbial cycling of major nutrients (carbon, nitrogen, phosphorus, and sulfur) helps maintain the high productivity of this ecosystem. However, mangrove ecosystems are being disturbed by the increasing concentration of greenhouse gases within the atmosphere. Both the anthropogenic and natural factors contribute to the upsurge of greenhouse gas concentration, resulting in global warming. Changing climate due to global warming and the increasing rate of human interferences such as pollution and deforestation are significant concerns for the mangrove ecosystem. Mangroves are susceptible to such environmental perturbations. Global warming, human interventions, and its consequences are destroying the ecosystem, and the dreadful impacts are experienced worldwide. Therefore, the conservation of mangrove ecosystems is necessary for protecting them from the changing environment-a step toward preserving the globe for better living. This review highlights the importance of mangroves and their microbial components on a global scale and the degree of vulnerability of the ecosystems toward anthropic and climate change factors. The future scenario of the mangrove ecosystem and the resilience of plants and microbes have also been discussed.

Multiple sclerosis patients have an altered gut mycobiome and increased fungal to bacterial richness

Trillions of microbes such as bacteria, fungi, and viruses exist in the healthy human gut microbiome. Although gut bacterial dysbiosis has been extensively studied in multiple sclerosis (MS), the significance of the fungal microbiome (mycobiome) is an understudied and neglected part of the intestinal microbiome in MS. The aim of this study was to characterize the gut mycobiome of patients with relapsing-remitting multiple sclerosis (RRMS), compare it to healthy controls, and examine its association with changes in the bacterial microbiome. We characterized and compared the mycobiome of 20 RRMS patients and 33 healthy controls (HC) using Internal Transcribed Spacer 2 (ITS2) and compared mycobiome interactions with the bacterial microbiome using 16S rRNA sequencing. Our results demonstrate an altered mycobiome in RRMS patients compared with HC. RRMS patients showed an increased abundance of Basidiomycota and decreased Ascomycota at the phylum level with an increased abundance of Candida and Epicoccum genera along with a decreased abundance of Saccharomyces compared to HC. We also observed an increased ITS2/16S ratio, altered fungal and bacterial associations, and altered fungal functional profiles in MS patients compared to HC. This study demonstrates that RRMS patients had a distinct mycobiome with associated changes in the bacterial microbiome compared to HC. There is an increased fungal to bacterial ratio as well as more diverse fungal-bacterial interactions in RRMS patients compared to HC. Our study is the first step towards future studies in delineating the mechanisms through which the fungal microbiome can influence MS disease.

Perspectives on the microorganism of extreme environments and their applications

Extremophiles are organisms that can survive and thrive in conditions termed as "extreme" by human beings. Conventional methods cannot be applied under extreme conditions like temperature and pH fluctuations, high salinity, etc. for a variety of reasons. Extremophiles can function and are adapted to thrive in these environments and are sustainable, cheaper, and efficient, therefore, they serve as better alternatives to the traditional methods. They adapt to these environments with biochemical and physiological changes and produce products like extremolytes, extremozymes, biosurfactants, etc., which are found to be useful in a wide range of industries like sustainable agriculture, food, cosmetics, and pharmaceuticals. These products also play a crucial role in bioremediation, production of biofuels, biorefinery, and astrobiology. This review paper comprehensively lists out the current applications of extremophiles and their products in various industries and explores the prospects of the same. They help us understand the underlying basis of biological mechanisms exploring the boundaries of life and thus help us understand the origin and evolution of life on Earth. This helps us in the research for extra-terrestrial life and space exploration. The structure and biochemical properties of extremophiles along with any possible long-term effects of their applications need to be investigated further.

Biochemistry, Synthesis, and Applications of Bacterial Cellulose: A Review

The potential of cellulose nanocomposites in the new-generation super-performing nanomaterials is huge, primarily in medical and environment sectors, and secondarily in food, paper, and cosmetic sectors. Despite substantial illumination on the molecular aspects of cellulose synthesis, various process features, namely, cellular export of the nascent polysaccharide chain and arrangement of cellulose fibrils into a quasi-crystalline configuration, remain obscure. To unleash its full potential, current knowledge on nanocellulose dispersion and disintegration of the fibrillar network and the organic/polymer chemistry needs expansion. Bacterial cellulose biosynthesis mechanism for scaled-up production, namely, the kinetics, pathogenicity, production cost, and product quality/consistency remain poorly understood. The bottom-up bacterial cellulose synthesis approach makes it an interesting area for still wider and promising high-end applications, primarily due to the nanosynthesis mechanism involved and the purity of the cellulose. This study attempts to identify the knowledge gap and potential wider applications of bacterial cellulose and bacterial nanocellulose. This review also highlights the manufacture of bacterial cellulose through low-cost substrates, that is, mainly waste from brewing, agriculture, food, and sugar industries as well as textile, lignocellulosic biorefineries, and pulp mills.

Biochemical Characterization of Thermostable Carboxymethyl Cellulase and β-Glucosidase from Aspergillus fumigatus JCM 10253

Second-generation biofuel production has emerged as a prominent sustainable and alternative energy. The biochemical properties of cellulolytic enzymes are imperative for cellulosic biomass conversion into fermentable sugars. In the present study, thermostable CMCase and β-glucosidase were purified and characterized from Aspergillus fumigatus JCM 10253. The enzymes were purified through 80% ammonium sulfate precipitation, followed by dialysis and DEAE-cellulose ion-exchange chromatography. The molecular masses of the purified CMCase and β-glucosidase were estimated to be 125 kDa and 90 kDa, respectively. The CMCase and β-glucosidase demonstrated optimum activities at pH 6.0 and 5.0, respectively. Their respective maximum temperatures were 50 and 60 °C. The cellulase activities were stimulated by 10 mM concentration of Ca²⁺, Ni²⁺, Fe²⁺, Mg²⁺, Cu²⁺, Mn²⁺, Zn²⁺, and Pb²⁺ ions. The CMCase activity was enhanced by surfactant Triton X-100 but marginally influenced by most inhibitors. The β-glucosidase retained its activity in the presence of organic solvents (30%) isoamyl alcohol, heptane, toluene, and ethyl acetate, while CMCase was retained with acetone during a prolonged incubation of 168 h. The K_m and V_max values of the two cellulases were studied. The properties of high thermostability and good tolerance against organic solvents could signify its potential use in biofuel production and other value-added products.

Coconut Mesocarp-Based Lignocellulosic Waste as a Substrate for Cellulase Production from High Promising Multienzyme-Producing Bacillus amyloliquefaciens FW2 without Pretreatments

Facing the crucial issue of high cost in cellulase production from commercial celluloses, inexpensive lignocellulosic materials from agricultural wastes have been attractive. Therefore, several studies have focused on increasing the efficiency of cellulase production by potential microorganisms capable of secreting a high and diversified amount of enzymes using agricultural waste as valuable substrates. Especially, extremophilic bacteria play an important role in biorefinery due to their high value catalytic enzymes that are active even under harsh environmental conditions. Therefore, in this study, we aim to investigate the ability to produce cellulase from coconut-mesocarp of the potential bacterial strain FW2 that was isolated from kitchen food waste in South Korea. This strain was tolerant in a wide range of temperature (−6–75 °C, pH range (4.5–12)) and at high salt concentration up to 35% NaCl. The molecular weight of the purified cellulase produced from strain FW2 was estimated to be 55 kDa. Optimal conditions for the enzyme activity using commercial substrates were found to be 40–50 °C, pH 7.0–7.5, and 0–10% NaCl observed in 920 U/mL of CMCase, 1300 U/mL of Avicelase, and 150 U/mL of FPase. It was achieved in 650 U/mL, 720 U/mL, and 140 U/mL of CMCase, Avicelase, and FPase using coconut-mesocarp, respectively. The results revealed that enzyme production by strain FW2 may have significant commercial values for industry, argo-waste treatment, and other potential applications.

Co-cultivation of T. asperellum GDFS1009 and B. amyloliquefaciens 1841: Strategy to regulate the production of ligno-cellulolytic enzymes for the lignocellulose biomass degradation

The influence of fossil fuels on the environment focused on the development of new technology on biofuels. In this situation, lignocellulolytic hydrolysis enzymes such as Cellobiohydrolase, β-Glucosidase, Endoglucanase, cellulase and xylanase have broad applications in the biofuel production. The Trichoderma have used for the production of cellulase and xylanase to hydrolyze the lignocellulose. Hence, in the present study, co-culture has been employed to induce the production of polysaccharide hydrolyzing enzymes under both induction and repression conditions. The enzyme activity and its gene expression were induced by the co-culture of T. asperellum and B. amyloliquefaciens compared to the monoculture. Further, the co-culture upregulated the transcription regulatory genes and downregulated the repressor genes under both repressor and inducer conditions, respectively. The crude enzyme produced by the co-culture and monocultures using the optimized medium containing molasses, cornmeal and rice bran were further used to hydrolyze the pretreated corn Stover, rice straw, and wheat straw. These results indicate that the co-culture of T. asperellum and B. amyloliquefaciens is a promising and inexpensive method to advance the innovation on the continuous production of cellulase and xylanase under different circumstances for the bioconversion of lignocellulosic biomass into glucose for the bio-fuels.

Psychrophilic Bacterial Phosphate-Biofertilizers: A Novel Extremophile for Sustainable Crop Production under Cold Environment

Abiotic stresses, including low-temperature environments, adversely affect the structure, composition, and physiological activities of soil microbiomes. Also, low temperatures disturb physiological and metabolic processes, leading to major crop losses worldwide. Extreme cold temperature habitats are, however, an interesting source of psychrophilic and psychrotolerant phosphate solubilizing bacteria (PSB) that can ameliorate the low-temperature conditions while maintaining their physiological activities. The production of antifreeze proteins and expression of stress-induced genes at low temperatures favors the survival of such organisms during cold stress. The ability to facilitate plant growth by supplying a major plant nutrient, phosphorus, in P-deficient soil is one of the novel functional properties of cold-tolerant PSB. By contrast, plants growing under stress conditions require cold-tolerant rhizosphere bacteria to enhance their performance. To this end, the use of psychrophilic PSB formulations has been found effective in yield optimization under temperature-stressed conditions. Most of the research has been done on microbial P biofertilizers impacting plant growth under normal cultivation practices but little attention has been paid to the plant growth-promoting activities of cold-tolerant PSB on crops growing in low-temperature environments. This scientific gap formed the basis of the present manuscript and explains the rationale for the introduction of cold-tolerant PSB in competitive agronomic practices, including the mechanism of solubilization/mineralization, release of biosensor active biomolecules, molecular engineering of PSB for increasing both P solubilizing/mineralizing efficiency, and host range. The impact of extreme cold on the physiological activities of plants and how plants overcome such stresses is discussed briefly. It is time to enlarge the prospects of psychrophilic/psychrotolerant phosphate biofertilizers and take advantage of their precious, fundamental, and economical but enormous plant growth augmenting potential to ameliorate stress and facilitate crop production to satisfy the food demands of frighteningly growing human populations. The production and application of cold-tolerant P-biofertilizers will recuperate sustainable agriculture in cold adaptive agrosystems.

Regulatory function of the novel transcription factor CxrC in Penicillium oxalicum

Numerous transcription factors (TFs) in ascomycete fungi play crucial roles in cellular processes; however, how most of them function is poorly understood. Here, we identified and characterized a novel TF, CxrC (POX01387), acting downstream of the key TF CxrA, which is essential for plant-biomass-degrading-enzyme (PBDE) production in Penicillium oxalicum. Deletion of cxrC in P. oxalicum significantly affected the production of PBDEs, as well as mycelial growth and conidiospore production. CxrA directly repressed the expression of cxrC after about 12 hr following switch to Avicel culture. CxrC bound the promoters of major PBDE genes and genes involved in conidiospore development. CxrC was found to bind the TSSGTYR core sequence (S: C and G; Y: T and C; R: G and A) of the important cellulase genes cbh1 and eg1. Both N- and C-terminal peptides of CxrC and the CxrC phosphorylation were found to mediate its homodimerization. The conserved motif LPSVRSLLTP (65-74) in CxrC was found to be required for regulating cellulase production. This study reveals novel mechanisms of TF-mediated regulation of the expression of PBDE genes and genes involved in cellular processes in an ascomycete fungus.

Partially purified actinomycetes compounds enhance the intracellular damages in multi-drug resistant P. aeruginosa and K. pneumoniae

Based on the excellent nutrient level, the current study was focused on isolation and anti-bacterial activity of the actinomycetes from marine mangrove soil samples. As result, 10 different strains of actinomycetes strains were identified on actinomycetes isolation agar plates. The identified strains were shown with white, clear, uncontaminated well matured spore producing ability. Based on the initial observation, the isolated colonies were actinomycetes. The partially extracted crude compound shown excellent anti-bacterial activity against P. aeruginosa and K. pneumoniae with 15 mm and 13 mm zone of inhibitions were observed at 500 μL concentrations. The minimum inhibition concentration result was also confirmed the 500 μL concentration against both the tested concentration with high inhibition rate. Then, the intracellular damages, decreased cell growth of the crude actinomycetes extract treated bacterial strains were clearly observed by confocal laser scanning electron microscope. The extracellular damages of bacterial cell wall and shape of the both the pathogens were clearly shown by scanning electron microscope. Therefore, all the results were clearly supported to the partially extracted crude compound and it has excellent anti-bacterial activity against tested multi drug resistant bacteria.

Microbial cellulases - An update towards its surface chemistry, genetic engineering and recovery for its biotechnological potential

The inherent resistance of lignocellulosic biomass makes it impervious for industrially important enzymes such as cellulases to hydrolyze cellulose. Further, the competitive absorption behavior of lignin and hemicellulose for cellulases, due to their electron-rich surfaces augments the inappropriate utilization of these enzymes. Hence, modification of the surface charge of the cellulases to reduce its non-specific binding to lignin and enhance its affinity for cellulose is an urgent necessity. Further, maintaining the stability of cellulases by the preservation of their secondary structures using immobilization techniques will also play an integral role in its industrial production. In silico approaches for increasing the catalytic activity of cellulase enzymes is also significant along with a range of substrate specificity. In addition, enhanced productivity of cellulases by tailoring the related genes through the process of genetic engineering and higher cellulase recovery after saccharification seems to be promising areas for efficient and large-scale enzyme production concepts.

Oxic and Anoxic Organic Polymer Degradation Potential of Endophytic Fungi From the Marine Macroalga, Ecklonia radiata

Cellulose and chitin are the most abundant polymeric, organic carbon source globally. Thus, microbes degrading these polymers significantly influence global carbon cycling and greenhouse gas production. Fungi are recognized as important for cellulose decomposition in terrestrial environments, but are far less studied in marine environments, where bacterial organic matter degradation pathways tend to receive more attention. In this study, we investigated the potential of fungi to degrade kelp detritus, which is a major source of cellulose in marine systems. Given that kelp detritus can be transported considerable distances in the marine environment, we were specifically interested in the capability of endophytic fungi, which are transported with detritus, to ultimately contribute to kelp detritus degradation. We isolated 10 species and two strains of endophytic fungi from the kelp Ecklonia radiata. We then used a dye decolorization assay to assess their ability to degrade organic polymers (lignin, cellulose, and hemicellulose) under both oxic and anoxic conditions and compared their degradation ability with common terrestrial fungi. Under oxic conditions, there was evidence that Ascomycota isolates produced cellulose-degrading extracellular enzymes (associated with manganese peroxidase and sulfur-containing lignin peroxidase), while Mucoromycota isolates appeared to produce both lignin and cellulose-degrading extracellular enzymes, and all Basidiomycota isolates produced lignin-degrading enzymes (associated with laccase and lignin peroxidase). Under anoxic conditions, only three kelp endophytes degraded cellulose. We concluded that kelp fungal endophytes can contribute to cellulose degradation in both oxic and anoxic environments. Thus, endophytic kelp fungi may play a significant role in marine carbon cycling via polymeric organic matter degradation.

Genome sequencing and identification of cellulase genes in Bacillus paralicheniformis strains from the Red Sea

Background

Cellulolytic microorganisms are considered a key player in the degradation of plant biomass in various environments. These microorganisms can be isolated from various environments, such as soils, the insect gut, the mammalian rumen and oceans. The Red Sea exhibits a unique environment in terms of presenting a high seawater temperature, high salinity, low nutrient levels and high biodiversity. However, there is little information regarding cellulase genes in the Red Sea environment. This study aimed to examine whether the Red Sea can be a resource for the bioprospecting of microbial cellulases by isolating cellulase-producing microorganisms from the Red Sea environment and characterizing cellulase genes.

Results

Three bacterial strains were successfully isolated from the plankton fraction and the surface of seagrass. The isolated strains were identified as Bacillus paralicheniformis and showed strong cellulase activity. These results suggested that these three isolates secreted active cellulases. By whole genome sequencing, we found 10 cellulase genes from the three isolates. We compared the expression of these cellulase genes under cellulase-inducing and non-inducing conditions and found that most of the cellulase genes were generally upregulated during cellulolysis in the isolates. Our operon structure analysis also showed that cellulase genes form operons with genes involved in various kinds of cellular reactions, such as protein metabolism, which suggests the existence of crosstalk between cellulolysis and other metabolic pathways in the bacterial isolates. These results suggest that multiple cellulases are playing important roles in cellulolysis.

Conclusions

Our study reports the isolation and characterization of cellulase-producing bacteria from the Red Sea. Our whole-genome sequencing classified our three isolates as Bacillus paralicheniformis, and we revealed the presence of ten cellulase orthologues in each of three isolates’ genomes. Our comparative expression analysis also identified that most of the cellulase genes were upregulated under the inducing conditions in general. Although cellulases have been roughly classified into three enzyme groups of beta-glucosidase, endo-β-1,4-glucanase and exoglucanase, these findings suggest the importance to consider microbial cellulolysis as a more complex reaction with various kinds of cellulase enzymes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02316-w.