Novel fungal consortium for bioremediation of metals and dyes from mixed waste stream

Potential of halophiles and alkaliphiles in bioremediation of azo dyes-laden textile wastewater: a review

Azo dye-laden textile wastewater must be treated before release due to various health and environmental concerns. Bioremediation of textile wastewater, however, is a challenge owing to its alkaline and saline nature as mesophilic microbes, in general, are either not able to thrive or show less efficiency under such hostile environment. Thus, pre-treatment for neutralization or salinity removal becomes a prerequisite before applying microbes for treatment, causing extra economical and technical burden. Extremophilic bacteria can be the promising bioremediating tool because of their inherent ability to survive and show toxicants removal capability under such extreme conditions without need of pre-treatment. Among extremophiles, halophilic and alkaliphilic bacteria which are naturally adapted to high salt and pH are of special interest for the decolorization of saline-alkaline-rich textile wastewater. The current review article is an attempt to provide an overview of the bioremediation of azo dyes and azo dye-laden textile wastewater using these two classes of extremophilic bacteria. The harmful effects of azo dyes on human health and environment have been discussed herein. Halo-alkaliphilic bacteria circumvent the extreme conditions by various adaptations, e.g., production of certain enzymes, adjustment at the protein level, pH homeostasis, and other structural adaptations that have been highlighted in this review. The unique properties of alkaliphiles and halophiles, to not only sustain but also harboring high dye removal competence at high pH and salt concentration, make them a good candidate for designing future bioremediation strategies for the management of alkaline, salt, and azo dye-laden industrial wastewaters.

Microbial innovations in chromium remediation: mechanistic insights and diverse applications

The ubiquity of hexavalent chromium (Cr(VI)) from industrial activities poses a critical environmental threat due to its persistence, toxicity and mutagenic potential. Traditional physico-chemical methods for its removal often entail significant environmental drawbacks. Recent advancements in remediation strategies have emphasized nano and bioremediation techniques as promising avenues for cost-effective and efficient Cr(VI) mitigation. Bioremediation harnesses the capabilities of biological agents like microorganisms, and algae to mitigate heavy metal contamination, while nano-remediation employs nanoparticles for adsorption purposes. Various microorganisms, including E. coli, Byssochlamys sp., Pannonibacter phragmitetus, Bacillus, Aspergillus, Trichoderma, Fusarium, and Chlorella utilize bioreduction, biotransformation, biosorption and bioaccumulation mechanisms to convert Cr(VI) to Cr(III). Their adaptability to different environments and integration with nanomaterials enhance microbial activity, offering eco-friendly solutions. The study provides a brief overview of metabolic pathways involved in Cr(VI) bioreduction facilitated by diverse microbial species. Nitroreductase and chromate reductase enzymes play key roles in nitrogen and chromium removal, with nitroreductase requiring nitrate and NADPH/NADH, while the chromium reductase pathway relies solely on NADPH/NADH. This review investigates the various anthropogenic activities contributing to Cr(VI) emissions and evaluates the efficacy of conventional, nano-remediation, and bioremediation approaches in curbing Cr(VI) concentrations. Additionally, it scrutinizes the mechanisms underlying nano-remediation techniques for a deeper understanding of the remediation process. It identifies research gaps and offers insights into future directions aimed at enhancing the real-time applicability of bioremediation methods for mitigating with Cr(VI) pollution and pave the way for sustainable remediation solutions.

Deciphering the role of fungus in degradation of polypropylene from hospital waste

Health and environmental consequences are unavoidable when it comes to management of hospital waste (HW) disposables. In order to eradicate the HW, this study isolated a novel fungus SPF21 from a hospital dumping yard to degrade Polypropylene (PP). We measured the attributes of PP inoculated with fungus using mass loss, Fourier trans-form infrared (FTIR), contact angle (CA), and scanning electron microscopy (SEM). The weight of PP exposed to SPF21 was reduced by 25% in 90 days. The SEM images reveal that there are pores all over the sample surface; they alsocaused voids during the biodegradation of PP. FTIR analysis indicates that the spectra of treated mask pieces show the absence of peak at 1746 cm-1 and the appearance of a new peak at 1643 cm-1 . A period of 90-day exposure to the fungal isolate SPF21 reduced the CA of PP by 44.8% when compared to the nonexposed PP samples, suggesting that the surface of PP turned more hydrophilic after exposure. Moreover, our study on PP degradation by the fungus Ascotricha sinuosa SPF21 appears to be promising from the perspective of environmental, health, and economic hazards. Our results indicate that biodegradation greatly facilitates fungus deposition and changes PP film morphology and hydrophilicity.

Microbial interactions within beneficial consortia promote soil health

By ecologically interacting with various biotic and abiotic agents acting in soil ecosystems, highly diverse soil microorganisms establish complex and stable assemblages and survive in a community context in natural settings. Besides facilitating soil microbiome to maintain great levels of population homeostasis, such microbial interactions drive soil microbes to function as the major engine of terrestrial biogeochemical cycling. It is verified that the regulative effect of microbe-microbe interplay plays an instrumental role in microbial-mediated promotion of soil health, including bioremediation of soil pollutants and biocontrol of soil-borne phytopathogens, which is considered an environmentally friendly strategy for ensuring the healthy condition of soils. Specifically, in microbial consortia, it has been proven that microorganism-microorganism interactions are involved in enhancing the soil health-promoting effectiveness (i.e., efficacies of pollution reduction and disease inhibition) of the beneficial microbes, here defined as soil health-promoting agents. These microbial interactions can positively regulate the soil health-enhancing effect by supporting those soil health-promoting agents utilized in combination, as multi-strain soil health-promoting agents, to overcome three main obstacles: inadequate soil colonization, insufficient soil contaminant eradication and inefficient soil-borne pathogen suppression, all of which can restrict their probiotic functionality. Yet the mechanisms underlying such beneficial interaction-related adjustments and how to efficiently assemble soil health-enhancing consortia with the guidance of microbe-microbe communications remain incompletely understood. In this review, we focus on bacterial and fungal soil health-promoting agents to summarize current research progress on the utilization of multi-strain soil health-promoting agents in the control of soil pollution and soil-borne plant diseases. We discuss potential microbial interaction-relevant mechanisms deployed by the probiotic microorganisms to upgrade their functions in managing soil health. We emphasize the interplay-related factors that should be taken into account when building soil health-promoting consortia, and propose a workflow for assembling them by employing a reductionist synthetic community approach.

Exploiting fungi in bioremediation for cleaning-up emerging pollutants in aquatic ecosystems

Aquatic pollution negatively affects water bodies, marine ecosystems, public health, and economy. Restoration of contaminated habitats has attracted global interest since protecting the health of marine ecosystems is crucial. Bioremediation is a cost-effective and eco-friendly way of transforming hazardous, resistant contaminants into environmentally benign products using diverse biological treatments. Because of their robust morphology and broad metabolic capabilities, fungi play an important role in bioremediation. This review summarizes the features employed by aquatic fungi for detoxification and subsequent bioremediation of different toxic and recalcitrant compounds in aquatic ecosystems. It also details how mycoremediation may convert chemically-suspended matters, microbial, nutritional, and oxygen-depleting aquatic contaminants into ecologically less hazardous products using multiple modes of action. Mycoremediation can also be considered in future research studies on aquatic, including marine, ecosystems as a possible tool for sustainable management, providing a foundation for selecting and utilizing fungi either independently or in microbial consortia.

Chromium Toxicity in Plants: Signaling, Mitigation, and Future Perspectives

Plants are very often confronted by different heavy metal (HM) stressors that adversely impair their growth and productivity. Among HMs, chromium (Cr) is one of the most prevalent toxic trace metals found in agricultural soils because of anthropogenic activities, lack of efficient treatment, and unregulated disposal. It has a huge detrimental impact on the physiological, biochemical, and molecular traits of crops, in addition to being carcinogenic to humans. In soil, Cr exists in different forms, including Cr (III) "trivalent" and Cr (VI) "hexavalent", but the most pervasive and severely hazardous form to the biota is Cr (VI). Despite extensive research on the effects of Cr stress, the exact molecular mechanisms of Cr sensing, uptake, translocation, phytotoxicity, transcript processing, translation, post-translational protein modifications, as well as plant defensive responses are still largely unknown. Even though plants lack a Cr transporter system, it is efficiently accumulated and transported by other essential ion transporters, hence posing a serious challenge to the development of Cr-tolerant cultivars. In this review, we discuss Cr toxicity in plants, signaling perception, and transduction. Further, we highlight various mitigation processes for Cr toxicity in plants, such as microbial, chemical, and nano-based priming. We also discuss the biotechnological advancements in mitigating Cr toxicity in plants using plant and microbiome engineering approaches. Additionally, we also highlight the role of molecular breeding in mitigating Cr toxicity in sustainable agriculture. Finally, some conclusions are drawn along with potential directions for future research in order to better comprehend Cr signaling pathways and its mitigation in sustainable agriculture.

A Feasibility Study on the Recall of Metallophilic Fungi from Fe(III)-Contaminated Soil and Evaluating Their Mycoremediation Capacity: Experimental and Theoretical Study

Mycoremediation is one of the most attractive, eco-friendly, and sustainable methods to mitigate the toxic effects of heavy metals. This study aimed to determine the mycoremediation capacity of metallophilic fungi isolated from heavy-metal-contaminated soil containing a high Fe(III) concentration (118.40 mg/kg). Four common fungal strains were isolated, including Curvularia lunata, Fusarium equiseti, Penicillium pinophilum, and Trichoderma harzianum. These fungal strains were exposed to gradually increasing concentrations of Fe(III) of 100, 200, 300, 400, 500, 600, 700, 800, 900, and 1000 mg/L. Sophisticated techniques and tests were employed to investigate the mycoremediation capability, including tolerance index (TI), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and adsorption isotherm. Furthermore, the impacts of initial concentration, pH, and temperature on the Fe(III) removal (%) and uptake capacity (mg/g) of the studied samples were investigated. The results were validated by statistical analysis using one-way ANOVA. It was found that the Fe(III) uptake with different ratios triggered alterations in the Fe(III) tolerance (TI) morphological (SEM), chemical (FTIR), and adsorption capacity properties. The highest Fe(III) tolerance for all studied fungal strains was achieved at 100 mg/L. Moreover, the optimum conditions of Fe(III) removal (%) for all studied fungal strains were within pH 7 and 28 °C, with similar performance at the initial Fe(III) concentration ranging from 50-200 mg/L. At the same time, the maximum Fe(III) uptake was achieved at pH 7, 20 °C, and 200 mg/L. Compared to other strains, the Fe(III) tolerance of T. harzianum was rise in the Fe(III) concentration. The Fe(III) uptake reaction was corroborated by best fitting with the Langmuir model, achieving optimum adsorption capacities of 61.34, 62.90, 63.30, and 72.46 mg/g for C.lunata, F. equiseti, P. pinophilum, T. harzianum, respectively. It can be deduced that the addressed fungi species can be applied in mycoremediation according to the utilized Fe(III) concentrations with more superiority for live T. harzianum.

Fungal bioproducts for petroleum hydrocarbons and toxic metals remediation: recent advances and emerging technologies

Petroleum hydrocarbons and toxic metals are sources of environmental contamination and are harmful to all ecosystems. Fungi have metabolic and morphological plasticity that turn them into potential prototypes for technological development in biological remediation of these contaminants due to their ability to interact with a specific contaminant and/or produced metabolites. Although fungal bioinoculants producing enzymes, biosurfactants, polymers, pigments and organic acids have potential to be protagonists in mycoremediation of hydrocarbons and toxic metals, they can still be only adjuvants together with bacteria, microalgae, plants or animals in such processes. However, the sudden accelerated development of emerging technologies related to the use of potential fungal bioproducts such as bioinoculants, enzymes and biosurfactants in the remediation of these contaminants, has boosted fungal bioprocesses to achieve higher performance and possible real application. In this review, we explore scientific and technological advances in bioprocesses related to the production and/or application of these potential fungal bioproducts when used in remediation of hydrocarbons and toxic metals from an integral perspective of biotechnological process development. In turn, it sheds light to overcome existing technological limitations or enable new experimental designs in the remediation of these and other emerging contaminants.

Autochthonous strains of Trichoderma isolated from tannery solid waste improve phytoextraction potential of heavy metals by sunflower

This research work was aimed at isolating and demonstrating the significant potential of autochthonous fungi for phytoextraction of hazardous metals in metal polluted soil using Helianthus annuus. Four multi-metal resistant strains of Trichoderma were selected from a total of 21 strains isolated from tannery polluted soil and tannery solid waste. Autochthonous Trichoderma strains were used singly and in the form of consortium (TC). Sunflower was grown in pots for 90 days having eight different amendments of tannery polluted soil with and without Trichoderma inoculation. Growth and biochemical attributes of the plants were observed along with metal content extract by different plant parts. The results revealed that TC enhanced shoot length, shoot dry weight, and metal uptake as compared to single specie inoculation. Similarly, BCF (72.8-118.23%) and TF were significantly pronounced in shoots of H. annuus grown with TC at 40% amended soil. The biochemical analysis of the plants showed that Trichoderma strains boosted the enzymatic (catalase, peroxidase, and superoxide dismutase) antioxidants in the plants. The use of indigenous fungi with metal accumulating plants like sunflower can help to alleviate metal contamination from industrial sites and can make the soil cultivable for energy crops.

Potential of indigenous ligno-cellulolytic microbial consortium to accelerate degradation of heterogenous crop residues

Indigenous microbial diversity has potential for rapid decomposition of residue through enzyme activities that is alternative, effective, and environment friendly strategy to accelerate degradation of lignocellulose in agricultural residues and make composting process economically viable. Keeping this view, the main objective of the present study was isolation and characterization of lignocellulosic degrading microbial diversity from long-term residue management practice experiments and to develop potential microbial consortium for rapid degradation of lignocellulosic biomass. In this study, twenty-five bacteria, nine fungi, and four actinomycetes isolates were obtained from the soil samples of different residue management fields from Ludhiana, Punjab, India. All isolates were qualitatively and quantitatively screened for enzyme activities, i.e., cellulase, xylanase, laccase, and lignin peroxidase. On the basis of quantitative estimation of enzyme activities, 3 fungal (S1F1, S2F4, and S6F9), 2 actinomycetes (S1A1 and S6A4), and 2 bacterial strains (S6B16 and S6B17) were further selected for in vitro bio-compatibility assay. Selected bio-compatible microbial strains were identified as Streptomyces flavomacrosporus (S6A4), Aspergillus terreus (S2F4), and Bacillus altitudinis (S6B16) through 16S rRNA and 18S rRNA sequencing. Furthermore, single and developed microbial consortium (S6B16 + S6A4 + S2F4) were screened for quantitative estimation of cellulase, xylanase, laccase, and lignin peroxidase enzymes with 23 biochemically different cereal, legume, and oil seed crop residues for optimization of enzyme activities at different time intervals. Results revealed that Vigna radiata followed by Cajanus cajan and Arachis hypogaea straw residue powder @ 1% in culture broth are a promising carbon source for B. altitudinis, S. flavomacrosporus, and A. terreus to produce higher ligno-cellulolytic microbial degrading enzymes due to variable range of carbon (C):nitrogen (N) ratio and higher ligno-cellulolytic content in the studied crop residues. Thus, the application of indigenous microbial consortium with efficient lignocellulose hydrolysis enzyme machinery might be an attractive alternative for ex situ crop residue management practices under sustainable manners.

Aspergillus violaceofuscus alleviates cadmium and chromium stress in Okra through biochemical modulation

Endophytic fungi from the Chilli were used to help okra plants exposed to cadmium (Cd) or chromium (Cr) stress. Initially, the strain Ch06 produced higher amounts of indole acetic acid (IAA) (230.5 μg/mL), sugar (130.7 μg/mL), proteins (128.2 μg/mL), phenolics (525.6 μg/mL) and flavonoids (98.4 μg/mL) in Czapek broth supplemented with Cd or Cr. The production of IAA and other metabolites in such a higher concentration suggested that Ch06 might improve plant growth under heavy metal stress. For this reason, an experiment was designed, in which biomass of Ch06 (at 2g/100g of sand) were applied to the okra plants exposed to Cd or Cr stress (at 100 or 500 μg/g). The results exhibited that Ch06 improved the total chlorophyll (36.4±0.2 SPAD), shoot length (22.6±0.2 cm), root length (9.1±0.6 cm), fresh weight (5±0.6 g), dry weight (1.25±0.01 g), sugars (151.6 μg/g), proteins (114.8 μg/g), proline (6.7 μg/g), flavonoids (37.9 μg/g), phenolics (70.7 μg/g), IAA (106.7 μg/g), catalase (0.75 enzyme units/g tissue) and ascorbic acid oxidaze (2.2 enzyme units/g tissue) of the associated okra plants. Similar observations have been recorded in Ch06 associated okra plants under Cd and Cr stress. Also, Ch06 association reduced translocation of Cd (35% and 45%) and Cr (47% and 53%) to the upper parts of the okra plants and thus reduced their toxicity. The internal transcribed spacer (ITS) region amplification of 18S rDNA (ribosomal deoxyribo nucleic acid) exhibited that the potent strain Ch06 was Aspergillus violaceofuscus. The results implied that A. violaceofuscus has the ability to promote host species growth exposed to Cd and Cr. Moreover, it helped the host plants to recover in Cd and Cr polluted soils, hence can be used as biofertilizer.

Fungal consortium of two Beauveria bassiana strains increases their virulence, growth, and resistance to stress: A metabolomic approach

The use of two or more microorganisms in a microbial consortium has been increasingly applied in the biological control of diseases and pests. Beauveria bassiana is one of the most widely studied fungal species in biological control, yet little is known about its role in fungal consortiums. In a previous study, our group found that a consortium formed by two strains of B. bassiana had significantly greater biocontrol potential against the polyphagous caterpillars Duponchelia fovealis (Lepidoptera: Crambidae) than either strain on its own. In this study, we use GC-MS and LC-MS/MS to evaluate and discuss the metabolomics of the consortium. A total of 21 consortium biomarkers were identified, corresponding to 14 detected by LC-MS/MS and seven by GC-MS. Antioxidant and anti-inflammatory mechanisms are the main properties of the metabolites produced by the consortium. These metabolites can depress the insect’s immune system, increasing its vulnerability and, hence, the fungal virulence of the consortium. In light of these results, we propose an action model of insect mortality due to the metabolites secreted by the consortium. The model includes the inhibition of defense mechanisms such as pro-inflammatory interleukin secretion, cell migration, cell aggregation, Dif, Dorsal and Relish gene transcription, and JAK/STAT and JNK signaling pathways. It also promotes the cleaning of oxidative molecules, like ROS, NOS, and H₂O₂, and the induction of virulence factors.

Bioremediation of greywater using a novel bacterial-fungal consortium: optimization and validation of the operating parameters in vitro

In the present study, removal of pollutants in greywater was investigated using a novel bacterial-fungal consortium. Response surface methodology was used for the optimization of process variables like pH, temperature, inoculum size, and Carbon/Nitrogen (C/N ratio) for degradation of pollutants. Experiments were based on Box Behnken statistical design and the results show a good fit with the quadratic model, coefficient of determination (R²) value of 0.9499. The reliability of the model was established by various statistical parameters like lack of fit, pure error, and residual sum of squares. The optimized conditions for maximum reduction in chemical oxygen demand, oil & grease and sulphate were found to be 78.7%, 82.6% and 89.7%, respectively after 96 h of incubation of the reaction mixture at pH 7; temperature 35°C; inoculum size 150 µl and C/N ratio of 1:2. Our results clearly demonstrate that the developed novel bacterial-fungal consortium can be a cost-effective, safe, and environment-friendly alternative for remediation of greywater.

Sustainable Application of Biosorption and Bioaccumulation of Persistent Pollutants in Wastewater Treatment: Current Practice

Persistent toxic substances including persistent organic pollutants and heavy metals have been released in high quantities in surface waters by industrial activities. Their presence in environmental compartments is causing harmful effects both on the environment and human health. It was shown that their removal from wastewaters using conventional methods and adsorbents is not always a sustainable process. In this circumstance, the use of microorganisms for pollutants uptake can be seen as being an environmentally-friendly and cost-effective strategy for the treatment of industrial effluents. However, in spite of their confirmed potential in the remediation of persistent pollutants, microorganisms are not yet applied at industrial scale. Thus, the current paper aims to synthesize and analyze the available data from literature to support the upscaling of microbial-based biosorption and bioaccumulation processes. The industrial sources of persistent pollutants, the microbial mechanisms for pollutant uptake and the significant results revealed so far in the scientific literature are identified and covered in this review. Moreover, the influence of different parameters affecting the performance of the discussed systems and also very important in designing of treatment processes are highly considered. The analysis performed in the paper offers an important perspective in making decisions for scaling-up and efficient operation, from the life cycle assessment point of view of wastewater microbial bioremediation. This is significant since the sustainability of the microbial-based remediation processes through standardized methodologies such as life cycle analysis (LCA), hasn’t been analyzed yet in the scientific literature.

Restoration of heavy metal-contaminated soil and water through biosorbents: A review of current understanding and future challenges

Heavy metal pollution in soil and water is a potential threat to human health as it renders food quality substandard. Different biosorbents such as microbial and agricultural biomass have been exploited for heavy metal immobilization in soil and sorptive removal in waters. Biosorption is an effective and sustainable method for heavy metal removal in soil and water, but the inherent challenges are to find cheap, selective, robust, and cost-effective bioadsorbents. Microbial and agricultural biomass and their modified forms such as nanocomposites and carbonaceous materials (viz., biochar, nanobiochar, biocarbon), might be useful for sequestration of heavy metals in soil via adsorption, ion exchange, complexation, precipitation, and enzymatic transformation mechanisms. In this review, potential biosorbents and their metal removal capacity in soil and water are discussed. The microbial adsorbents and modified composites of agricultural biomasses show improved performance, stability, reusability, and effectively immobilize heavy metals from soil and water. In the future, researchers may consider the modified composites, encapsulated biosorbents for soil and water remediation.

Biochars derived from bamboo and rice straw for sorption of basic red dyes

The primary purpose of this study is to eliminate Basic Red 46 dye from aqueous solutions utilizing batch experiments by adsorption on biochars prepared from bamboo and rice straw biomass. Biochars prepared from bamboo (B), and rice straw (R) was pyrolyzed at 500°C (B500 and R500). Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) Spectroscopy, X-ray Diffraction (XRD), and surface area and porosity analyzers were used to characterize the B500 and R500 samples. The characterization results indicated that the biochars possessed an amorphous porous structure with many functional groups consisting primarily of silicates. The adsorption rate of BR46 was evaluated using two kinetic models (pseudo-first-order and pseudo-second-order), and the results indicated that the pseudo-second-order model fitted to the experimental data well (R2>0.99). Nearly 24 h was sufficient to achieve equilibrium with the dye adsorption for the two biochars. R500 had a greater adsorption efficiency than B500. As pH levels increased, the dye's adsorption capability increased as well. The Langmuir and Freundlich isotherm models were used to investigate the equilibrium behavior of BR46 adsorption, and the equilibrium data fitted well with the Langmuir model (R2>0.99) compared to the Freundlich model (R2>0.89). The maximum adsorption capacities of BR46 are 9.06 mg/g for B500 and 22.12 mg/g for R500, respectively. Additionally, adsorption capacity increased as temperature increased, indicating that adsorption is favored at higher temperatures. The electrostatic interaction is shown to be the dominant mechanism of BR46 adsorption, and BR46 acts as an electron-acceptor, contributing to n-π EDA (Electron Donor-Acceptor) interaction. Thermodynamic parameters for the dye-adsorbent system revealed that the adsorption process is spontaneous and feasible. The values of the adsorption coefficient (Kd) were on the order of 102-103. Kd of R500 was greater than that of B500, indicating that R500 had a greater adsorption capacity. The results showed that R500 could be used as a low-cost alternative adsorbent for removing BR46 from effluents.

Bioremediation of Chromium by Microorganisms and Its Mechanisms Related to Functional Groups

Heavy metals generated mainly through many anthropogenic processes, and some natural processes have been a great environmental challenge and continued to be the concern of many researchers and environmental scientists. This is mainly due to their highest toxicity even at a minimum concentration as they are nonbiodegradable and can persist in the aquatic and terrestrial environments for long periods. Chromium ions, especially hexavalent ions (Cr(VI)) generated through the different industrial process such as tanneries, metallurgical, petroleum, refractory, oil well drilling, electroplating, mining, textile, pulp and paper industries, are among toxic heavy metal ions, which pose toxic effects to human, plants, microorganisms, and aquatic lives. This review work is aimed at biosorption of hexavalent chromium (Cr(VI)) through microbial biomass, mainly bacteria, fungi, and microalgae, factors influencing the biosorption of chromium by microorganisms and the mechanism involved in the remediation process and the functional groups participated in the uptake of toxic Cr(VI) from contaminated environments by biosorbents. The biosorption process is relatively more advantageous over conventional remediation technique as it is rapid, economical, requires minimal preparatory steps, efficient, needs no toxic chemicals, and allows regeneration of biosorbent at the end of the process. Also, the presence of multiple functional groups in microbial cell surfaces and more active binding sites allow easy uptake and binding of a greater number of toxic heavy metal ions from polluted samples. This could be useful in creating new insights into the development and advancement of future technologies for future research on the bioremediation of toxic heavy metals at the industrial scale.

Evaluation of the Potential of Sewage Sludge Mycobiome to Degrade High Diclofenac and Bisphenol-A Concentrations

One of the most challenging environmental threats of the last two decades is the effects of emerging pollutants (EPs) such as pharmaceutical compounds or industrial additives. Diclofenac and bisphenol A have regularly been found in wastewater treatment plants, and in soils and water bodies because of their extensive usage and their recalcitrant nature. Due to the fact of this adversity, fungal communities play an important role in being able to safely degrade EPs. In this work, we obtained a sewage sludge sample to study both the culturable and non-culturable microorganisms through DNA extraction and massive sequencing using Illumina MiSeq techniques, with the goal of finding degraders adapted to polluted environments. Afterward, degradation experiments on diclofenac and bisphenol A were performed with the best fungal degraders. The analysis of bacterial diversity showed that Dethiosulfovibrionaceae, Comamonadaceae, and Isosphaeraceae were the most abundant families. A predominance of Ascomycota fungi in the culturable and non-culturable population was also detected. Species such as Talaromyces gossypii, Syncephalastrum monosporum, Aspergillus tabacinus, and Talaromyces verruculosus had remarkable degradation rates, up to 80% of diclofenac and bisphenol A was fully degraded. These results highlight the importance of characterizing autochthonous microorganisms and the possibility of selecting native fungal microorganisms to develop tailored biotransformation technologies for EPs.

Insights into nanomycoremediation: Secretomics and mycogenic biopolymer nanocomposites for heavy metal detoxification

Our environment thrives on the subtle balance achieved by the forever cyclical nature of building and rebuilding life through natural processes. Fungi, being the evident armor of bioremediation, is the indispensable element of the soil food web, contribute to be the nature's most dynamic arsenal with non-specific enzymes like peroxidase (POX), glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), non-enzymatic compounds like thiol (-SH) groups and non-protein compounds such as glutathione (GSH) and metallothionein (MT). Recently, the area of nanomycoremediation has been gaining momentum as a powerful tool for environmental clean-up strategies with its ability to detoxify heavy metals with its unique characteristics to adapt mechanisms such as biosorption, bioconversion, and biodegradation to harmless end products. The insight into the elaborate secretomic processes provides us with huge opportunities for creating a magnificent living bioremediation apparatus. This review discusses the scope and recent advances in the lesser understood area, nanomycoremediation, the state-of-the-art, innovative, cost-effective and promising tool for detoxification of heavy metal pollutants and focuses on the metabolic capabilities and secretomics with nanobiotechnological interventions.

Fungi and biochar applications in bioremediation of organic micropollutants from aquatic media

The conventional wastewater treatment system such as bacteria, is not able to remove recalcitrant micropollutants effectively. While, fungi have shown high capacity in degradation of recalcitrant compounds. Biochar, on the other hand, has gained attention in water and wastewater treatment as a low cost and sustainable adsorbent. This paper aims to review the recent applications of three major fungal divisions including Basidiomycota, Ascomycota, and Mucoromycotina, in organic micropollutants removal from wastewater. Moreover, it presents an insight into fungal bioreactors, fungal biofilm and immobilization system. Biochar adsorption capacities for organic micropollutants removal under different operating conditions are summarized. Finally, few recommendations for further research are established in the context of the combination of fungal biofilm with the technologies relying on the adsorption by porous carbonaceous materials.

Comparative Utilization of Dead and Live Fungal Biomass for the Removal of Heavy Metal: A Concise Review

Human and industrial activities produce and discharge wastes containing heavy metals into the water resources making them polluted, threatening human health and the ecosystem. Biosorption, the process of passive cation binding by dead or living biomass, represents a potentially cost-effective way of eliminating toxic heavy metals from industrial wastewater. The abilities of microorganisms to remove metal ions in solution have been extensively studied; in particular, live and dead fungi have been recognized as a promising class of low-cost adsorbents for the removal of heavy metal ions. The biosorption behavior of fungal biomass is getting attention due to its several advantages; hence, it needs to be explored further to take its maximum advantage on wastewater treatment. This review discusses the live and dead fungi characteristics of sorption, factors influencing heavy metal removal, and the biosorption capacities for heavy metal ions removal and also discusses the biosorption mechanisms.

Role of Bacterial-Fungal Consortium for Enhancement in the Degradation of Industrial Dyes

Background

The presence of anthraquinone (Disperse blue 64) and azodyes (Acid yellow 17) in a waterbody are considered among the most dangerous pollutants.

Methods

In this study, two different isolated microbes, bacterium and fungus, were individually and as a co-culture applied for the degradation of Disperse Blue 64 (DB 64) and Acid Yellow 17 (AY 17) dyes. The isolates were genetically identified based upon 16S (for bacteria) and ITS/5.8S (for fungus) rRNA genes sequences as Pseudomoans aeruginosa and Aspergillus flavus, respectively.

Results

The fungal/bacterial consortium exhibited a higher percentage of dyes degradation than the individual strains, even at a high concentration of 300 mg/L. Azoreductase could be identified as the main catabolic enzyme and the consortium could induce azoreductase enzyme in the presence of both dyes. However, the specific substrate which achieved the highest azoreductase specific activity was Methyl red (MR) (3.5 U/mg protein). The tentatively proposed metabolites that were detected by HPLC/MS suggested that the reduction process catalyzed the degradation of dyes. The metabolites produced by the action consortium on two dyes were safe on Vicia faba and Triticum vulgaris germination and health of seedlings. Toxicity of the dyes and their degradation products on the plant was different according to the type and chemistry of these compounds as well as the type of irrigated seeds.

Conclusion

We submit that the effective microbial degradation of DB64 and AY17 dyes will lead to safer metabolic products.

Use of soil fungi in the biosorption of three trace metals (Cd, Cu, Pb): promising candidates for treatment technology?

Trace metal contamination is a widespread and complex environmental problem. Because fungi are capable of growing in adverse environments, several fungal species could have an interesting potential in remediation technologies for metal contaminated environments. This study proposes to test the ability to tolerate and biosorb three trace metals (Cd, Cu and Pb) of 28 fungal isolates collected from different soils. First, a tolerance assay in agar medium was performed. Each isolate was grown in the presence of Cd, Cu, and Pb at different concentrations. Then, we exposed each soil fungus to 50 mg L^-1 of Cd, Cu, or Pb during 3 days in liquid medium. Parameters such as biomass production, pH, and biosorption were evaluated. The results showed that responses to metal exposure are very diverse even with fungi isolated from the same soil sample, or belonging to the same genera. Several isolates could be considered as good metal biosorbents and could be used in future mycoremediation studies. Among the 28 fungi tested, Absidia cylindrospora biosorbed more than 45% of Cd and Pb, Chaetomium atrobrunneum biosorbed more than 45% of Cd, Cu, Pb, and Coprinellus micaceus biosorbed 100% of Pb.

Effective mycoremediation coupled with bioaugmentation studies: An advanced study on newly isolated Aspergillus sp. in Type-II pyrethroid-contaminated soil

The intensive application of type-II pyrethroid worldwide in agricultural and residential practices potentially contributes to soil and water pollution, raising various concerns about environmental and public health. In the present study, robust fungus (strain PYR-P2) with high pyrethroids degradation potential was isolated from pesticide-contaminated soil. The strain was identified based on morphology and molecular characteristics, as Aspergillus sp. The screening of the transforming ability of strain PYR-P2 was evaluated in minimal salt media (MSM), where the fungus utilized up to 500 mg L^-1 of pyrethroid mixture (cypermethrin (CYP), cyfluthrin (CYF), cyhalothrin (CYH)). With this in view, central composite design (CCD) with three independent variables (pH, temperature, and initial concentration) was employed to identify the optimal conditions for achieving maximum pyrethroid removal. Under optimal conditions, strain PYR-P2 was implemented for the bioaugmentation studies in natural and sterile soil (NS/SS) systems spiked with pyrethroid (single and mixture) at a concentration of 100 mg kg^-1. The highest pyrethroid removal percentages were observed in fungally augmented NS, accompanied by a decrease in pyrethroid half-life (t_1/2). Herein, the observed half-life (t_1/2) of pyrethroids in the fungally augmented NS varied between 1.48 and 2.69 d, with equally good values recorded in SS as 1.65-3.10 d. Taken together, the mycoremediation study employing fungal (strain PYR-P2) augmentation under optimized conditions represents an efficient strategy to restore pyrethroid-contaminated soil.

Multiple heavy metal tolerance and removal by an earthworm gut fungus Trichoderma brevicompactum QYCD-6

Fungal bioremediation is a promising approach to remove heavy-metal from contaminated water. Present study examined the ability of an earthworm gut fungus Trichoderma brevicompactum QYCD-6 to tolerate and remove both individual and multi-metals. The minimum inhibitory concentration (MIC) of heavy metals [Cu(II), Cr(VI), Cd(II) and Zn(II)] against the fungus was ranged 150–200 mg L⁻¹ on composite medium, and MIC of Pb(II) was the highest with 1600 mg L⁻¹ on potato dextrose (PD) medium. The Pb(II) presented the highest metal removal rate (97.5%) which mostly dependent on bioaccumulation with 80.0%, and synchronized with max biomass (6.13 g L⁻¹) in PD medium. However, on the composite medium, the highest removal rate was observed for Cu(II) (64.5%). Cellular changes in fungus were reflected by TEM analysis. FTIR and solid-state NMR analyses indicated the involvement of different functional groups (amino, carbonyl, hydroxyl, et al.) in metallic biosorption. These results established that the earthworm-associated T. brevicompactum QYCD-6 was a promising fungus for the remediation of heavy-metal wastewater.

The improved methods of heavy metals removal by biosorbents: A review

For decades, a vast array of innovative biosorbents have been found out and used in the removal of heavy metals, including bacteria, algae and fungi, etc. Although extensive biological species have been tried as a biosorbent for heavy metals removal, for removal efficiency or economy efficiency limited, it has failed to make a substantial breakthrough in practical application. Thus, many improved methods based on biosorbents emerged. In this review, based on the literature and our research results, we highlight three types of novel methods for biosorbents removal of heavy metals: chemical modification of biosorbents; biomass and chemical materials combination; multiple biomass complex systems. We mainly focus on their configuration, biosorption performance, their creation method, regeneration/reuse, their application and development in the future. Through the comparative analysis of various methods, we think that intracellular autogenous nanomaterials may open up another window in biosorption of heavy metals area. At the same time, the combination of various treatment methods will be the development tendency of heavy metal pollution treatment in the future.

Biodegradation of Reactive Orange 16 azo dye by simultaneous action of Pleurotus ostreatus and the yeast Candida zeylanoides

The purpose was to investigate a simultaneous biodegradation of the recalcitrant monoazo dye Reactive Orange 16 (RO16) in a mixed culture consisting of a biofilm of Pleurotus ostreatus-colonizing polyamide carrier and a suspension of the yeast Candida zeylanoides to see their biological interactions and possible synergistic action during degradation. Decolorization in the mixed culture was more effective than in the fungal monoculture, the respective decolorizations reaching 87.5% and 70% on day 11. The proliferation of yeast was reduced compared with the C. zeylanoides monoculture but enabled the yeast to participate in decolorization. The interaction of P. ostreatus with the yeast resulted in a gradual decrease of fungal manganese-dependent peroxidase (MnP) and laccase activities. Gas chromatography-mass spectrometry (GC-MS) analysis of the degradation products brought evidence that P. ostreatus split the dye molecule asymmetrically to provide 4-(ethenylsulfonyl) benzene whose concentration was much decreased in the mixed culture suggesting its increased metabolization in the presence of the yeast. In contrast, C. zeylanoides split the azo bond symmetrically producing the metabolites 4-(ethenylsulfonyl) aniline and α-hydroxybenzenepropanoic acid. Those metabolites were rapidly degraded in the mixed culture. A novel aspect is represented by the evidence of a mutual cooperative action of the fungal and yeast microorganisms in the mixed culture resulting in rapid decolorization and degradation of the dye.

Chromium tolerance and accumulation in Aspergillus flavus isolated from tannery effluent

Cr(VI) tolerance in Aspergillus flavus, strain SFL, isolated from tannery effluent was measured and compared with a reference strain of A. flavus, A1120. On solid medium, SFL had a high level of Cr(VI) tolerance (1,600 mg/L), which was 16 times that of A1120 and greater than most previously analyzed fungal strains. When in 100 mg/L of Cr(VI), SFL completely depleted Cr(VI) within 72 h while A1120 depleted 85% of Cr(VI). SFL was more effective in reducing extracellular Cr(VI) than A1120. While A1120 showed greater biosorption of Cr(VI) than SFL, intracellular accumulation was approximately 50% greater in SFL and was more energy-dependent than A1120. Cr(VI) modified the external surface of the hyphae. Cr speciation detected the presence of only Cr(III), corresponding to Cr(OH)₃ , which precipitated on the hyphal surface. Cr(VI) bound to the functional groups carboxyl, amine, and hydroxyl in both SFL and A1120. Transmission electron microscopy energy-dispersive X-ray detected Cr on the fungal wall and within membrane-bound organelles of the cytoplasm. In conclusion, the greater tolerance of SFL to Cr(VI) relative to A1120 is due to more effective energy-dependant uptake of Cr(VI) into the cell and increased capacity of SFL to store Cr in intracellular vacuoles compared with A1120.

Biodegradation of reactive textile dye Novacron Super Black G by free cells of newly isolated Alcaligenes faecalis AZ26 and Bacillus spp obtained from textile effluents

Bacteria were isolated from effluents of textile industries and screened by their capability to decolorize at least one of eight reactive dyes used in the textile industries. Three isolates having the capability to decolorize the highest number of dyes with more than 25% of decolorization were identified as Alcaligenes faecalis AZ26, Bacillus cereus AZ27 and Bacillus sp. AZ28 based on morphological, cultural, biochemical characteristics, and 16S rDNA sequence analysis. The decolorization capability of these three bacterial isolates was optimized under different physicochemical conditions by using Novacron Super Black G (NSB-G), one of the eight reactive dyes commonly used in textile industries. These bacterial isolates grew well in the presence of up to 500 mg L⁻¹ of NSB-G and showed decolorization of approximately 90% at 200 mg L⁻¹ of NSB-G after 96 h of cultivation at 37 °C and pH 8.0 under static condition. Decolorization of NSB-G by the bacterial isolates was investigated using UV-VIS spectrophotometry and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The UV-visible absorbance spectra and the FTIR spectrum of the decolorized NSB-G significantly differed from those of the parent dye, indicating that the NSB-G was degraded by the bacterial isolates. High decolorization extent supports the notion that the bacterial isolates reported herein might have potential in the biological treatment of dyeing mill effluents.

Manganese affects the growth and metabolism of Ganoderma lucidum based on LC-MS analysis

Background

As a metal-enriched edible fungus, Ganoderma lucidum is capable of adsorbing manganese effectively. And the manganese ion is demonstrated to play an important role in the synthesis of manganese peroxidase (Mnp) and other physiological activities during G. lucidum growth. Recently, the influence of manganese on the metabolites of G. lucidum fruiting bodies can be revealed through metabonomics technique.

Methods

In this study, we uncovered the changes between the control and 200 mg/kg Mn-treated fruiting bodies with liquid chromatography coupled to mass spectrometry (LC-MS).

Results

The mycelial growth rate, dry yield, Mnp activity , total polysaccharide content, triterpenoid content, and total manganese content in the mature fruiting bodies of G. lucidum changed between the control and different Mn-treated groups. Based on LC-MS method, a total of 16 significantly different metabolites were obtained and identified, among which, five presented significantly down-regulated and 11 up-regulated in Mn-treated samples. The metabolites chavicol and palmitoylethanolamide were particularly significantly up-regulated, and were found the strong promotion relationship. Dependent on the MetPA database, four KEGG pathways were detected and glycerophospholipid metabolism was most impacted, in which, choline was involved in.

Discussion

The added manganese ion in the substrate enhanced Mnp activities, and consequently promoted the mycelial growth, yield , metabolites in the fruiting bodies including triterpenoids, total manganese, chavicol, etc. Our finding can provide a theoretical reference to regulation of manganese on the physiological metabolism of G. lucidum.

Enhanced organics and Cu2+ removal in electroplating wastewater by bioaugmentation

With the improvement of electroplating process and products requirement, refractory organics, heavy metals or even heavy metal nanoparticles (NP) exist simultaneously in electroplating wastewater inevitably, makes electroplating wastewater treatment effluent difficult to meet the discharge standard. In order to improve the organics removal under the exposure of CuO NP, strains (designated as L1-L5) that have both organics degradation and Cu²⁺ tolerance capacities were isolated and employed in the electroplating wastewater bioaugmentation treatment using a hydrolytic/anoxic/oxic-membrane bioreactor. The Cu²⁺ adsorption process followed pseudo-second order kinetics and the isotherms fit well to Langmuir isotherm model. L2, L3 and L4 showed higher Cu²⁺ adsorption capacity than that of L1 and L5. Under the optimal condition, the maximum Cu²⁺ adsorption capacity of L2, L3 and L4 was 34.15, 45.68 and 26.72 mg g^-1, respectively. Their average COD removal efficiency achieved 65.7 ± 10.9%, 61.5 ± 6.7% and 71.6 ± 6.0%, respectively. The three isolates were used to construct consortia with the inoculum concentration of 400 mg L^-1. One-time and repeated inoculations were evaluated to find the applicable strategy. Repeated inoculation resulted in a better COD and Cu removal performance (76.2 ± 2.6% and 98.5 ± 0.3%, respectively) than those of one-time inoculation (69.0 ± 2.0% and 98.0 ± 0.3%, respectively). The most functionally stable, balanced and resistant bacterial community was formed in the one-time inoculation system while for fungal community it was formed in the repeated inoculation system.

Removal of industrial dyes and heavy metals by Beauveria bassiana: FTIR, SEM, TEM and AFM investigations with Pb(II)

Presence of industrial dyes and heavy metal as a contaminant in environment poses a great risk to human health. In order to develop a potential technology for remediation of dyes (Reactive remazol red, Yellow 3RS, Indanthrene blue and Vat novatic grey) and heavy metal [Cu(II), Ni(II), Cd(II), Zn(II), Cr(VI) and Pb(II)] contamination, present study was performed with entomopathogenic fungi, Beauveria bassiana (MTCC no. 4580). High dye removal (88-97%) was observed during the growth of B. bassiana while removal percentage for heavy metals ranged from 58 to 75%. Further, detailed investigations were performed with Pb(II) in terms of growth kinetics, effect of process parameters and mechanism of removal. Growth rate decreased from 0.118 h^-1 (control) to 0.031 h^-1, showing 28% reduction in biomass at 30 mg L^-1 Pb(II) with 58.4% metal removal. Maximum Pb(II) removal was observed at 30 °C, neutral pH and 30 mg L^-1 initial metal concentration. FTIR analysis indicated the changes induced by Pb(II) in functional groups on biomass surface. Further, microscopic analysis (SEM and atomic force microscopy (AFM)) was performed to understand the changes in cell surface morphology of the fungal cell. SEM micrograph showed a clear deformation of fungal hyphae, whereas AFM studies proved the increase in surface roughness (RSM) in comparison to control cell. Homogenous bioaccumulation of Pb(II) inside the fungal cell was clearly depicted by TEM-high-angle annular dark field coupled with EDX. Present study provides an insight into the mechanism of Pb(II) bioremediation and strengthens the significance of using entomopathogenic fungus such as B. bassiana for metal and dye removal.

Diversity-Function Relationships in Natural, Applied, and Engineered Microbial Ecosystems

The connection between ecosystem function and taxonomic diversity has been of interest and relevance to macroecologists for decades. After many years of lagging behind due to the difficulty of assigning both taxonomy and function to poorly distinguishable microscopic cells, microbial ecology now has access to a suite of powerful molecular tools which allow its practitioners to generate data relating to diversity and function of a microbial community on an unprecedented scale. Instead, the problem facing today's microbial ecologists is coupling the ease of generation of these datasets with the formulation and testing of workable hypotheses relating the diversity and function of environmental, host-associated, and engineered microbial communities. Here, we review the current state of knowledge regarding the links between taxonomic alpha- and beta-diversity and ecosystem function, comparing our knowledge in this area to that obtained by macroecologists who use more traditional techniques. We consider the methodologies that can be applied to study these properties and how successful they are at linking function to diversity, using examples from the study of model microbial ecosystems, methanogenic bioreactors (anaerobic digesters), and host-associated microbiota. Finally, we assess ways in which our newly acquired understanding might be used to manipulate diversity in ecosystems of interest in order to improve function for the benefit of us or the environment in general through the provision of ecosystem services.

Overview on the Biochemical Potential of Filamentous Fungi to Degrade Pharmaceutical Compounds

Pharmaceuticals represent an immense business with increased demand due to intensive livestock raising and an aging human population, which guarantee the quality of human life and well-being. However, the development of removal technologies for these compounds is not keeping pace with the swift increase in their use. Pharmaceuticals constitute a potential risk group of multiclass chemicals of increasing concern since they are extremely frequent in all environments and have started to exhibit negative effects on micro- and macro-fauna as well as on human health. In this context, fungi are known to be extremely diverse and poorly studied microorganisms despite being well suited for bioremediation processes, taking into account their metabolic and physiological characteristics for the transformation of even highly toxic xenobiotic compounds. Increasing studies indicate that fungi can transform many structures of pharmaceutical compounds, including anti-inflammatories, β-blockers, and antibiotics. This is possible due to different mechanisms in combination with the extracellular and intracellular enzymes, which have broad of biotechnological applications. Thus, fungi and their enzymes could represent a promising tool to deal with this environmental problem. Here, we review the studies performed on pharmaceutical compounds biodegradation by the great diversity of these eukaryotes. We examine the state of the art of the current application of the Basidiomycota division, best known in this field, as well as the assembly of novel biodegradation pathways within the Ascomycota division and the Mucoromycotina subdivision from the standpoint of shared enzymatic systems, particularly for the cytochrome P450 superfamily of enzymes, which appear to be the key enzymes in these catabolic processes. Finally, we discuss the latest advances in the field of genetic engineering for their further application.

Biological Removal of the Mixed Pharmaceuticals: Diclofenac, Ibuprofen, and Sulfamethoxazole Using a Bacterial Consortium

Background: The presence of pharmaceuticals at low concentrations (ng to μg) in the environment has become a hot spot for researchers in the past decades due to the unknown environmental impact and the possible damages they might have to the plantae and fauna present in the aquatic systems, as well as to the other living organisms. Objectives: The aim of the present investigation was to develop a bacterial consortium isolated from different origins to evaluate the ability of such a consortium to remove a mixture of pharmaceuticals in the batch system at lab scale, as well as assessment of its resistance to the other micropollutants present in the environment. Material and Methods: Using a closed bottle test, biodegradation of the mixed pharmaceuticals including Diclofenac (DCF), Ibuprofen (IBU), and Sulfamethoxazole (SMX) (at a concentration of 3 mg.L^-1 of each drug) by the bacterial consortium was investigated. The test was carried out under metabolic (pharmaceutical was used as the sole source of carbon) and co-metabolic condition (in the presence of glucose). Finally, the ability of the bacterial consortium to resist other micropollutants like antibiotics and heavy metals was investigated. Results: Under the metabolic condition, the mixed bacteria (i.e., consortium) were able to metabolize 23.08% and 9.12% of IBU, and DCF at a concentration of 3 mg.L^-1 of each drug, respectively. Whereas, in co-metabolic conditions, IBU was eliminated totally, in addition, 56% of the total concentration of DCF was removed, as well. In both metabolic and cometabolic conditions, removal of SMX was not observed. The selected bacteria were able to resist to most of the applied antibiotics and the used heavy metals, except mercury, where only one strain (S4) was resistant to the later heavy metal. Conclusion: Results suggest that the developed consortium might be an excellent candidate for the application in the bioremediation process for treating ecosystems contaminated with the pharmaceutical.

Effect of yeasts on biodegradation potential of immobilized cultures of white rot fungi

The aim was to investigate the effect of yeast organisms on the degradation process by immobilized cultures of ligninolytic fungi. Immobilization was accomplished by 7-day colonization of polyamide mesh with mycelial fragments. Irpex lacteus decolorized >90% of the initial concentration of 150mgl^-1 of anthraquinone Remazol Brilliant Blue R dye in three subsequent decolorization cycles and the degradation capacity was not negatively affected by the presence of 10⁶Saccharomyces cerevisiae cells per ml in the mixed culture. The yeast was not able to degrade the dye. I. lacteus biofilm was also resistant to bacterial infection with E. coli. Inoculation of the yeast to pre-formed I. lacteus biofilm culture resulted in a reduction of fungal biomass by 27%. Levels of LiP, MnP and laccase of I. lacteus were not much influenced by S. cerevisiae or E. coli. Similar resilience of P. ostreatus biofilms was observed after exposure to yeast Issatchenkia occidentalis when the fungal degradation capacity measured with Reactive Orange 16 azo dye was maintained over two decolorization cycles. I. occidentalis did not degrade the dye under the conditions used. Formation of densely packed fungal biofilms with abundant extracellular polysaccharide was not impeded by the yeast. Increase of MnP and laccase levels attributable to the presence of I. occidentalis was observed.

Endophytic Paecilomyces formosus LHL10 Augments Glycine max L. Adaptation to Ni-Contamination through Affecting Endogenous Phytohormones and Oxidative Stress

This study investigated the Ni-removal efficiency of phytohormone-producing endophytic fungi Penicillium janthinellum, Paecilomyces formosus, Exophiala sp., and Preussia sp. Among four different endophytes, P. formosus LHL10 was able to tolerate up to 1 mM Ni in contaminated media as compared to copper and cadmium. P. formosus LHL10 was further assessed for its potential to enhance the phytoremediation of Glycine max (soybean) in response to dose-dependent increases in soil Ni (0.5, 1.0, and 5.0 mM). Inoculation with P. formosus LHL10 significantly increased plant biomass and growth attributes as compared to non-inoculated control plants with or without Ni contamination. LHL10 enhanced the translocation of Ni from the root to the shoot as compared to the control. In addition, P. formosus LHL10 modulated the physio-chemical apparatus of soybean plants during Ni-contamination by reducing lipid peroxidation and the accumulation of linolenic acid, glutathione, peroxidase, polyphenol oxidase, catalase, and superoxide dismutase. Stress-responsive phytohormones such as abscisic acid and jasmonic acid were significantly down-regulated in fungal-inoculated soybean plants under Ni stress. LHL10 Ni-remediation potential can be attributed to its phytohormonal synthesis related genetic makeup. RT-PCR analysis showed the expression of indole-3-acetamide hydrolase, aldehyde dehydrogenase for indole-acetic acid and geranylgeranyl-diphosphate synthase, ent-kaurene oxidase (P450-4), C13-oxidase (P450-3) for gibberellins synthesis. In conclusion, the inoculation of P. formosus can significantly improve plant growth in Ni-polluted soils, and assist in improving the phytoremediation abilities of economically important crops.

Comparative performance evaluation of multi-metal resistant fungal strains for simultaneous removal of multiple hazardous metals

In the present study, five fungal strains viz., Aspergillus terreus AML02, Paecilomyces fumosoroseus 4099, Beauveria bassiana 4580, Aspergillus terreus PD-17, Aspergillus fumigatus PD-18, were screened for simultaneous multimetal removal. Highest metal tolerance index for each individual metal viz., Cd, Cr, Cu, Ni, Pb and Zn (500mg/L) was recorded for A. fumigatus for the metals (Cd, 0.72; Cu, 0.72; Pb, 1.02; Zn, 0.94) followed by B. bassiana for the metals (Cd, 0.56; Cu, 0.14; Ni, 0.29; Zn, 0.85). Next, the strains were exposed to multiple metal mixture (Cd, Cr, Cu, Ni, Pb and Zn) of various concentrations (6, 12, 18, 30mg/L). Compared to other strains, B. bassiana and A. fumigatus had higher cube root growth (k) constants indicating their better adaptability to multi metal stress. After 72h, multimetal accumulation potential of B. bassiana (26.94±0.07mg/L) and A. fumigatus (27.59±0.09mg/L) were higher than the other strains at initial multimetal concentration of 30mg/L. However, considering the post treatment concentrations of individual metals in multimetal mixture (at all the tested concentrations), A. fumigatus demonstrated exceptional performance and could bring down the concentrations of Cd, Cu, Ni, Pb and Zn below the threshold level for irrigation prescribed by Food and Agriculture Organization (FAO).

Effect of metal ions and petrochemicals on bioremediation of chlorpyrifos in aerobic sequencing batch bioreactor (ASBR)

Application of chlorpyrifos (CP) has increased its environmental concentration. Increasing CP concentration has increased chances of adverse health effects. Its removal from environment has attained researcher's attention. CP degrading bacterial strains were isolated from wastewater and agricultural soil. Finally, selected five bacterial strains were identified using 16S rRNA nucleotide sequence analysis as Pseudomonas kilonensis SRK1, Serratia marcescens SRK2, Bacillus pumilus SRK4, Achromobacter xylosoxidans SRK5, and Klebsiella sp. T13. Interaction studies among bacterial strains demonstrated possibility for development of five membered bacterial consortium. Biodegradation potential of bacterial consortium was investigated in the presence of petrochemicals and trace metals. About 98 % CP removal was observed in sequencing batch reactors at inoculum level, 10 %; pH, 7; CP concentration, 400 mgL^-1, and HRT, 48 h. Experimental data has shown an excellent fit to first order growth model. Among all petrochemicals only toluene (in low concentration) has stimulatory effect on biodegradation of CP. Addition of petrochemicals (benzene, toluene, and xylene) in high concentration (100 mg L^-1) inhibited bacterial activity and decreased CP removal. At low concentration i.e., 1 mg L^-1 of inorganic contaminants (Cu, Hg, and Zn) >96 % degradation was observed. Addition of Cu(II) in low concentration has stimulated CP removal efficiency. Hg(II) in all concentrations has strongly inhibited biodegradation rate except at 1 mgL^-1. In simulated pesticide, wastewater CP removal efficiency decreased to 77.5 %. Outcomes of study showed that both type and concentration of petrochemicals and trace metals influenced biodegradation of CP.

Multiple heavy metal removal using an entomopathogenic fungi Beauveria bassiana

Towards the development of a potential remediation technology for multiple heavy metals [Zn(II), Cu(II), Cd(II), Cr(VI) and Ni(II)] from contaminated water, present study examined the growth kinetics and heavy metal removal ability of Beauveria bassiana in individual and multi metals. The specific growth rate of B. bassiana varied from 0.025h(-1) to 0.039h(-1) in presence of individual/multi heavy metals. FTIR analysis indicated the involvement of different surface functional groups in biosorption of different metals, while cellular changes in fungus was reflected by various microscopic (SEM, AFM and TEM) analysis. TEM studies proved removal of heavy metals via sorption and accumulation processes, whereas AFM studies revealed increase in cell surface roughness in fungal cells exposed to heavy metals. Present study delivers first report on the mechanism of bioremediation of heavy metals when present individually as well as multi metal mixture by entomopathogenic fungi.

Diverse Metabolic Capacities of Fungi for Bioremediation

Bioremediation refers to cost-effective and environment-friendly method for converting the toxic, recalcitrant pollutants into environmentally benign products through the action of various biological treatments. Fungi play a major role in bioremediation owing to their robust morphology and diverse metabolic capacity. The review focuses on different fungal groups from a variety of habitats with their role in bioremediation of different toxic and recalcitrant compounds; persistent organic pollutants, textile dyes, effluents from textile, bleached kraft pulp, leather tanning industries, petroleum, polyaromatic hydrocarbons, pharmaceuticals and personal care products, and pesticides. Bioremediation of toxic organics by fungi is the most sustainable and green route for cleanup of contaminated sites and we discuss the multiple modes employed by fungi for detoxification of different toxic and recalcitrant compounds including prominent fungal enzymes viz., catalases, laccases, peroxidases and cyrochrome P450 monooxygeneses. We have also discussed the recent advances in enzyme engineering and genomics and research being carried out to trace the less understood bioremediation pathways.

Immobilization of horseradish peroxidase onto kaolin

Kaolin showed as a very perspective carrier for the enzyme immobilization and it was used for the adsorption of horseradish peroxidase (HRP). The effects of the enzyme concentration and pH on the immobilization efficiency were studied in the reaction with pyrogallol and anthraquinone dye C.I. Acid Violet 109 (AV 109). In addition, Fourier transform infrared spectroscopy, scanning electron microscopy and analysis by Brunauer-Emmett-Teller were performed for kaolin, thermally activated kaolin and the immobilized enzyme. It has been shown that 0.1 IU of HRP-kaolin decolorized 87 % of dye solution, under the optimal conditions (pH 5.0, temperature 24 °C, dye concentration 40 mg/L and 0.2 mM of H2O2) within 40 min. The immobilized HRP decolorization follows the Ping Pong Bi-Bi mechanism with dead-end inhibition by the dye. The biocatalyst retained 35 ± 0.9 % of the initial activity after seven cycles of reuse in the decolorization reaction of AV 109 under optimal conditions in a batch reactor. The obtained kinetic parameters and reusability study confirmed improvement in performances of k-HRP compared to free, indicating that k-HRP has a great potential for environmental purposes.