Toxicity evaluation and biodegradation of phenanthrene by laccase from Trametes polyzona PBURU 12

Biodegradation of low-density polyethylene by mixed fungi composed of Alternaria sp. and Trametes sp. isolated from landfill sites

With the development of industry and modern manufacturing, nondegradable low-density polyethylene (LDPE) has been widely used, posing a rising environmental hazard to natural ecosystems and public health. In this study, we isolated a series of LDPE-degrading fungi from landfill sites and carried out LDPE degradation experiments by combining highly efficient degrading fungi in pairs. The results showed that the mixed microorganisms composed of Alternaria sp. CPEF-1 and Trametes sp. PE2F-4 (H-3 group) had a greater degradation effect on heat-treated LDPE (T-LDPE). After 30 days of inoculation with combination strain H-3, the weight loss rate of the T-LDPE film was approximately 154% higher than that of the untreated LDPE (U-LDPE) film, and the weight loss rate reached 0.66 ± 0.06%. Environmental scanning electron microscopy (ESEM) and Fourier transform infrared spectroscopy (FTIR) were used to further investigate the biodegradation impacts of T-LDPE, including the changes on the surface and depolymerization of the LDPE films during the fungal degradation process. Our findings revealed that the combined fungal treatment is more effective at degrading T-LDPE than the single strain treatment, and it is expected that properly altering the composition of the microbial community can help lessen the detrimental impact of plastics on the environment.

Low toxicity of magnetite-based modified bionanocomposites with potential application for wastewater treatment: Evaluation in a zebrafish animal model

In recent years, the escalating concerns surrounding environmental pollution and the need for sustainable wastewater treatment solutions have underscored the significance of developing technologies that can efficiently treat wastewater while also reducing negative ecological effects. In this context, our study aims to contribute to the advancement of sustainable technologies for wastewater treatment, by investigating the effects that bare magnetite nanoparticles and those functionalized with the enzyme laccase could have in an aquatic animal, zebrafish, at various life cycle stages. Exposure to magnetite nanoparticles shows some effects on embryo hatching, survival rates, or larval behavior at higher concentrations. For both treatments, the hatching percentages were close to 80% compared to 93% for the control group. At the end of the observations in larvae, survival in all the evaluated groups was higher than 90%. Additionally, we evaluated the accumulation of nanoparticles in various stages of zebrafish. We found that, although there was accumulation during embryonic stages, it did not affect normal development or subsequent hatching. Iron levels in different organs such as gills, muscles, gastrointestinal tract, and brain were also evaluated in adults. Animals treated with a mix of food and nanoparticles at 10 μg/mL (Food group) presented a higher concentration of iron accumulation in muscle, gastrointestinal tract, and gills compared to the untreated control group. Although iron levels increased depending on the dose and exposure method applied, they were not statistically significant from the control groups. Our findings suggest that bionanocomposites evaluated here can be considered safe for removal of contaminants in wastewater without toxic effects or detrimental accumulation fish's health.

New insights in the biodegradation of high-cyclic polycyclic aromatic hydrocarbons with crude enzymes of Trametes versicolor

High-cyclic polycyclic aromatic hydrocarbons (PAHs), with complex fused aromatic structures, are widespread, refractory and harmful in soil, but the current remediation technologies for high-cyclic PAHs are often inefficient and costly. This study focused on the biodegradation process of high-cyclic benzo[a]pyrene by Trametes versicolor crude enzymes. The crude enzymes exhibited high laccase activity (22112 U/L) and benzo[a]pyrene degradation efficiency (42.21%) within a short reaction time. Through the actual degradation and degradation kinetics, the degradation efficiency of PAHs decreased with the increase of aromatic rings. And the degradation conditions (temperature, pH, Cu2+ concentration, mediator) were systematically optimised. The optimum degradation conditions (1.5 mM Cu2+, 28℃ and pH 6) showed significant degradation efficiency for the low and medium concentrations of benzo[a]pyrene. In addition, complete degradation of benzo[a]pyrene could be achieved using only 0.2 mM of HBT mediator compared with crude enzymes alone. Collectively, these results showed the high-cyclic PAHs degradation potential of Trametes versicolor crude enzymes, and provided references to evaluate applicable prospects of white rot fungus crude enzymes in PAHs-contaminated soils.

Fungal bioremediation approaches for the removal of toxic pollutants: Mechanistic understanding for biorefinery applications

Pollution is a global menace that poses harmful effects on all the living ecosystems and to the Earth. As years pass by, the available and the looming rate of pollutants increases at a faster rate. Although many treatments and processing strategies are waged for treating such pollutants, the by-products and the wastes or drain off generated by these treatments further engages in the emission of hazardous waste. Innovative and long-lasting solutions are required to address the urgent global issue of hazardous pollutant remediation from contaminated environments. Myco-remediation is a top-down green and eco-friendly tool for pollution management. It is a cost-effective and safer practice of converting pernicious substances into non-toxic forms by the use of fungi. But these pollutants can be transformed into useable products along with multiple benefits for the environment such as sequestration of carbon emissions and also to generate high valuable bioactive materials that fits as a sustainable economic model. The current study has examined the possible applications of fungi in biorefineries and their critical role in the transformation and detoxification of pollutants. The paper offers important insights into using fungal bioremediation for both economically and environmentally sound solutions in the domain of biorefinery applications by combining recent research findings.

Antiproliferative activity and apoptosis‑inducing effects of Trametes polyzona polysaccharides against human breast cancer cells

Fungal polysaccharides have garnered interest due to their biological activities in terms of anticancer properties and antioxidant activity. The present study aimed to evaluate the anticancer properties and antioxidant activity of a newly isolated white-rot fungus, Trametes polyzona CU07 from Thailand. Crude T. polyzona polysaccharides (CTPPs) were extracted from mycelia using hot water. The chemical properties, including total carbohydrates, molecular weight and protein content, and Fourier-transform infrared spectroscopy analysis, were then investigated. The antioxidant activity was determined against the radicals 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The anticancer properties were evaluated in MCF-7 breast cancer (BC) cells, whereas the 293 cell line was used as a control. The inhibitory effects of CTPPs on viability were determined by MTT assay, followed by BrdU incorporation assay to assess cell proliferation. The induction of apoptosis was determined by flow cytometry. CTPPs were considered polysaccharide-protein conjugates, which had molecular weights in the range of 0.3-22,528 kDa. They contained ~50 and 37% carbohydrate and protein, respectively, with glucose as the main monosaccharide component. Notably, CTPPs had high antioxidant activity against ABTS, and had a significant inhibitory effect on the MCF-7 cell line with a half-maximal inhibitory concentration value of 0.58 mg/ml. However, they exhibited little effect on the 293 cell line. The BrdU incorporation assay demonstrated that CTPPs inhibited proliferation by ~20% compared with that in untreated cells. CTPPs also induced early- and late-stage apoptosis of MCF-7 cells. These results indicated that the CTPPs may exhibit potential antiproliferative and antioxidant activity, and apoptosis-inducing effects against human BC cells.

Degradation of crude oil-associated polycyclic aromatic hydrocarbons by marine-derived fungi

One of the major environmental concerns today is hydrocarbon contamination resulting from the activities related to the petrochemical industry. Crude oil is a complex mixture of hydrocarbons like alkanes, naphthene and polycyclic aromatic hydrocarbons (PAHs). PAHs are known to be highly toxic to humans and animals due to their carcinogenic and mutagenic effects. PAHs are environmentally recalcitrant due to their hydrophobicity which makes them difficult to degrade, thus making them persistent environmental contaminants. The mechanical and chemical methods in practice currently to remove hydrocarbon contaminants have limited effectiveness and are expensive. Bioremediation is a cost-effective technology for treating hydrocarbon-contaminated sites as it results in the complete mineralisation of the pollutant. This study demonstrates the degradation of crude oil and associated PAHs using ten fungal cultures isolated from the aquatic environment. The current study reported a 98.6% and 92.9% reduction in total PAHs in crude oil by Fusarium species, i.e. isolate NIOSN-T4 and NIOSN-T5, respectively. The fungal isolate, NIOSN-T4, identified as Fusarium equiseti, showed maximum PAH degradation efficiency of LMW PAHs 97.8%. NIOSN-M126, identified as Penicillium citrinum, exhibited a 100% removal of HMW PAHs. Microorganisms possess an untapped potential for various applications in biotechnology, and the current study demonstrated the potential of marine fungi for use in the bioremediation of xenobiotic hydrocarbons in the environment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03753-2.

Molecular advances in mycoremediation of polycyclic aromatic hydrocarbons: Exploring fungal bacterial interactions

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous high global concern environmental pollutants and tend to bioaccumulate due to hydrophobic properties. These xenobiotics, having variable concentrations along different matrices, gradually undergo various physical, chemical, and biological transformation processes. Myco-remediation aids accelerated degradation by effectively transforming complex ring structures to oxidized/hydroxylated intermediates, which can further funnel to bacterial degradation pathways. Exploitation of such complementing fungal-bacterial enzymatic activity can overcome certain limitations of incomplete bioremediation process. Furthermore, high-throughput molecular methods can be employed to unveil community structure, taxon abundance, coexisting community interactions, and metabolic pathways under stressed conditions. The present review critically discusses the role of different fungal phyla in PAHs biotransformation and application of fungal-bacterial cocultures for enhanced mineralization. Moreover, recent advances in bioassays for PAH residue detection, monitoring, developing xenobiotics stress-tolerant strains, and application of fungal catabolic enzymes are highlighted. Application of next-generation sequencing methods to reveal complex ecological networks based on microbial community interactions and data analysis bias in performing such studies is further discussed in detail. Conclusively, the review underscores the application of mixed-culture approach by critically highlighting in situ fungal-bacterial community nexus and its role in complete mineralization of PAHs for the management of contaminated sites.

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.

Biotransformation as a tool for remediation of polycyclic aromatic hydrocarbons from polluted environment - review on toxicity and treatment technologies

Polycyclic aromatic hydrocarbons, a prominent family of persistent organic molecules produced by both anthropogenic and natural processes, are widespread in terrestrial and aquatic environments owing to their hydrophobicity, electrochemical stability and low aqueous solubility. Phenanthrene and naphthalene belong to the group of polycyclic aromatic hydrocarbons whose occurrence are reported to be relatively higher. The bioremediation mode of removing the toxicities of these two compounds has been reported to be promising than other methods. Most of the microbial classes of bacterial, fungal and algal origin are reported to degrade the target pollutants into non-toxic compounds effectively. The review aims to give an overview on toxicological studies, identification and enrichment techniques of phenanthrene and naphthalene degrading microbes and the bioremediation technologies (microbial assisted reactors, microbial fuel cells and microbial assisted constructed wetlands) reported by various researchers. All the three modes of bioremediation techniques were proved to be promising on different perspectives. In the treatment of phenanthrene, a maximum recovery of 96% and 98% was achieved in an aerobic membrane reactor with Bacillus species and single chamber air cathode microbial fuel cell with Acidovorax and Aquamicrobium respectively were reported. With the constructed wetland configuration, 95.5% of removal was attained with manganese oxide based microbial constructed wetland. The maximum degradation efficiency reported for naphthalene are 99% in a reverse membrane bioreactor, 98.5% in a marine sediment microbial fuel cell and 92.8% with a low-cost sandy soil constructed wetland.