The dynamic of cellulase activity of fungi inhabiting organic municipal solid waste

Mucor septatiphorus nom. nov. and other Mucor species recorded from the Brazilian upland forest

During a survey of mucoralean diversity in three different fragments of upland forest located in the semi-arid region of Pernambuco, Brazil, 14 species of Mucor were recorded; twelve of them reported for the first time from upland forest areas. We propose a replacement name for Mucor septatus nom. illeg. and present detailed descriptions and illustrations of the specimens isolated.

Current state of the art biotechnological strategies for conversion of watermelon wastes residues to biopolymers production: A review

Poly-3-hydroxyalkanoates (PHA) are biodegradable and compostable polyesters. This review is aimed to provide a unique approach that can help think tanks to frame strategies aiming for clean technology by utilizing cutting edge biotechnological advances to convert fruit and vegetable waste to biopolymer. A PHA manufacturing method based on watermelon waste residue that does not require extensive pretreatment provides a more environmentally friendly and sustainable approach that utilizes an agricultural waste stream. Incorporating fruit processing industry by-products and water, and other resource conservation methods would not only make the manufacturing of microbial bio-plastics like PHA more eco-friendly, but will also help our sector transition to a bioeconomy with circular product streams. The final and most critical element of this review is an in-depth examination of the several hazards inherent in PHA manufacturing.

Bioprocess potential of Eco-friendly fungal isolates converting organic waste to bioresource

This study aims to present indigenous fungal diversity in the soil sample collected from solid waste disposal site. The synthesis of cellulase enzymes via in laboratory scale study has been performed using indigenous fungus isolates. Additionally; its impact has been evaluated on the basis of the bioconversion of organic waste treated employing screened potential cellulase producer fungi which is further used for primary and secondary screening of cellulolytic. The findings advised that, a total of 27 fungal isolates belonging to twenty-four genera were reported as most potential fungal strains. The findings indicates a highest exo-β-glucanase (C1) enzymatic action was observed by fungal strains T. harzianum, T. viride , A. niger. These isolates are promising and could be suitable candidate for biodegradation of organic waste due to its's well established extraordinary ability. Therefore, these fungal isolates are suggested for more in depth research in order to use for recycling of organic waste.

Adaptive laboratory evolution of Escherichia coli W enhances gamma-aminobutyric acid production using glycerol as the carbon source

The microbial conversion of glycerol into value-added commodity products has emerged as an attractive means to meet the demands of biosustainability. However, glycerol is a non-preferential carbon source for productive fermentation because of its low energy density. We employed evolutionary and metabolic engineering in tandem to construct an Escherichia coli strain with improved GABA production using glycerol as the feedstock carbon. Adaptive evolution of E. coli W under glycerol-limited conditions for 1300 generations harnessed an adapted strain with a metabolic system optimized for glycerol utilization. Mutation profiling, enzyme kinetic assays, and transcriptome analysis of the adapted strain allowed us to decipher the basis of glycerol adaptation at the molecular level. Importantly, increased substrate influx mediated by the mutant glpK and modulation of intracellular cAMP levels were the key drivers of improved fitness in the glycerol-limited condition. Leveraging the enhanced capability of glycerol utilization in the strain, we constructed a GABA-producing E. coli W-derivative with superior GABA production compared to the wild-type. Furthermore, rationally designed inactivation of the non-essential metabolic genes, including ackA, mgsA, and gabT, in the glycerol-adapted strain improved the final GABA titer and specific productivity by 3.9- and 4.3-fold, respectively, compared with the wild-type.

Microbial succession and molecular ecological networks response to the addition of superphosphate and phosphogypsum during swine manure composting

This study assessed the effects of superphosphate (SPP) and phosphogypsum (PPG) on the bacterial and fungal community succession and molecular ecological networks during composting. Adding SPP and PPG had positive effects on the bacterial richness and diversity, negative effects on the fungal richness and diversity. The microbial diversity and richness were higher in PPG than SPP. Non-metric multidimensional scaling analysis clearly separated SPP and PPG from the control treatment with no additives. The dominant genera comprised Turicibacter, Bacillus, norank_o_SBR1031, Thermobifida, norank_f_Limnochordaceae, Truepera, Thermopolyspora, Mycothermus, Dipodascus, Thermomyces, and unclassified_p_Ascomycota. In all treatments, the major bacterial species differed clearly in the later thermophilic, cooling, and maturation composting stages, whereas the main fungal species varied significantly in the thermophilic stage. The changes in the dominant microorganisms in SPP and PPG may have inhibited or promoted the degradation of organic matter during various composting stages. Adding SPP and PPG led to more complex bacterial networks and less complex fungal networks, where SPP had more adverse effects on the fungal networks than PPG. SPP and PPG could potentially alter the co-occurrence patterns of the bacterial and fungal communities by changing the most influential species. SPP and PPG changed the composition and succession of the microbial community by influencing different physiochemical properties during various composting stages where the pH was the main explanatory factor. Overall, this study provides new insights into the effects of SPP and PPG on the microbial community and its interactions during composting.

Improving β-glucosidase and xylanase production in a combination of waste substrate from domestic wastewater treatment system and agriculture residues

Cellulase and hemicellulase activities are considered to the major bottlenecks in the lignocellulosic biorefinery process, especially in an enzyme cocktail lacking β-glucosidase (BGL) and xylanase (XYL). In view of this issue, higher levels of BGL and XYL activities were obtained in the presence of wastewater and activated sludge as an induction medium mixed with 5% of rice straw by Hypocrea sp. W₆₃. The analysis of the ionic content showed that a relatively low sludge dose could enhance the production of BGL and XYL. Most importantly, compared to a medium using freshwater, the proportion of 1:10 sludge to wastewater, which contained nutrient elements, led to 3.4-fold BGL and 3.7-fold XYL production improvements. This research describes the reuse of substrates that are largely and continuously generated from domestic wastewater treatment systems and agriculture residues, which consequently leads to the development of a simultaneous enzyme production process for sustainable biorefinery practices.

Hierarchical porous carbon fabricated from cellulose-degrading fungus modified rice husks: Ultrahigh surface area and impressive improvement in toluene adsorption

The porous carbon materials formed from biomass precursors are promising candidates for adsorbing organic vapor pollutants. However, these materials have insufficient pores, which hinder their accessibility to adsorbates. This study develops an ultrahigh-surface-area porous carbon adsorbent with interlacing micro-mesoporous structures through Trichoderma viride decomposition. An orthogonal experiment is conducted, and the most suitable conditions for fabricating porous carbon with an ultrahigh S_BET of 3714 m².g^-1 and a hierarchical porous structure are identified. This work achieves one of the highest specific surface areas of biomass carbons among recent studies. T. viride corrodes the internal and external microstructures of rice husks, and regulates the lignin, cellulose, and hemicellulose contents, which improve the efficiency of carbonization and chemical activation. The carbonaceous materials with microbial pretreatment exhibit better toluene adsorption performances (100 ppm: 708 mg.g^-1), adsorption rates, and cyclic utilization than those without pretreatment (100 pm: 538 mg.g^-1). In addition, grand canonical Monte Carlo simulation is conducted. The micropores and mesopores created after microbial pretreatment are effective toluene adsorption sites. Moreover, the diffusion coefficient calculated by utilizing Thomas model and Chemical diffusion verify that the mesopores accelerate the kinetic process of toluene adsorption.

Resource recovery and circular economy from organic solid waste using aerobic and anaerobic digestion technologies

With the inevitable rise in human population, resource recovery from waste stream is becoming important for a sustainable economy, conservation of the ecosystem as well as for reducing the dependence on the finite natural resources. In this regard, a bio-based circular economy considers organic wastes and residues as potential resources that can be utilized to supply chemicals, nutrients, and fuels needed by mankind. This review explored the role of aerobic and anaerobic digestion technologies for the advancement of a bio-based circular society. The developed routes within the anaerobic digestion domain, such as the production of biogas and other high-value chemicals (volatile fatty acids) were discussed. The potential to recover important nutrients, such as nitrogen through composting, was also addressed. An emphasis was made on the innovative models for improved economics and process performance, which include co-digestion of various organic solid wastes, recovery of multiple bio-products, and integrated bioprocesses.

Changes in global trends in food waste composting: Research challenges and opportunities

Increasing food waste (FW) generation has put significant pressure on the environment and has increased the global financial costs of its appropriate management. Among the traditional organic waste recycling technologies (i.e., incineration, landfilling and anaerobic digestion), composting is an economically feasible and reliable technology for FW recycling regardless of its technical flaws and social issues. The global scenario of FW generation, technical advancement in FW composting and essential nutrient recovery from organic waste with waste recycling are discussed in this article. Recent research on various strategies to improve FW composting, including co-composting, the addition of organic/inorganic additives, the mitigation of gaseous emission, and microbiological variations are comprehensively explained. Subsequently, it is shown that the performing FW composting in an existing mechanical facility can improve organic waste degradation and produce value-added mature compost to save on costs and increase the technological feasibility and viability of FW composting to some extent.

Microbial dynamics for lignocellulosic waste bioconversion and its importance with modern circular economy, challenges and future perspectives

An extensive use of microbial dynamics for utilizing the lignocellulosic wastes has been attributed to their efficiency in bioenergy and bioproducts development as a cost effective high nutritional value. The integration of lignocellulosic waste into the circular economy can scaleup the sustainable bioproducts and bioenergy development. In this review paper, the aim is to describe the existing research efforts on organic lignocellulosic waste, cellulase producing microbes, their potential enzyme, modern circular economy with associated challenges and future perspectives. Presently, it has been reviewed that microbial cellulases have provided treasure bioproducts visions into industrial bioproducts marvels unveiled through lignocellulosic waste cutting-edge microbial explorations. Furthermore, the review focused on new insights of the growing circular economy of lignocellulosic waste used for many bioproducts and bioenergy dealings and explored the emergent lignocellulosic biorefinery approaches which could then be applied to review industrial-scale sustainable economic models for upgraded bioproducts and other production associated problems.

Developments and opportunities in fungal strain engineering for the production of novel enzymes and enzyme cocktails for plant biomass degradation

Fungal strain engineering is commonly used in many areas of biotechnology, including the production of plant biomass degrading enzymes. Its aim varies from the production of specific enzymes to overall increased enzyme production levels and modification of the composition of the enzyme set that is produced by the fungus. Strain engineering involves a diverse range of methodologies, including classical mutagenesis, genetic engineering and genome editing. In this review, the main approaches for strain engineering of filamentous fungi in the field of plant biomass degradation will be discussed, including recent and not yet implemented methods, such as CRISPR/Cas9 genome editing and adaptive evolution.

Dynamics of fungal diversity and interactions with environmental elements in response to wheat straw biochar amended poultry manure composting

The fungal dynamics and its correlation with physicochemical and gaseous emission were investigated using metagenomics and Heat map illustrator (HEMI). Five different concentrations of wheat straw biochar (WSB) were applied to poultry manure (PM) and composted for 50 days; those without the WSB treatment were used as a control. The results revealed the dominant phyla to be Chytridiomycota, Mucoromycota, Ascomycota and Basidiomycota, while Batrachochytrium, Rhizophagus, Mucor, and Puccinia were the superior genera. In particular, the diversity of Chytridiomycota and Ascomycota was more abundant among all of the treatments. Overall, the diversity of the fungal species was correspondent, but relative abundance varied significantly among all of the composts. Principle Coordinate Analysis (PCoA) and Non-Metric Multi- Dimensional Scaling (NMDS) indicated that different concentrations of WSB applied treatments have significantly distinct fungal communities. In addition, correlation analyses of fungal interactions with environmental elements via HEMI also indicate a clear difference among the treatments. Ultimately, the relative abundance of fungal composition significantly influenced the PM compost treated by the WSB.