Decolorization and detoxification of different azo dyes by Phanerochaete chrysosporium ME-446 under submerged fermentation

Successful cultivation of edible fungi on textile waste offers a new avenue for bioremediation and potential food production

Textile waste contains both natural fibres such as cotton and bamboo viscose, and synthetic fibres such as elastane and polyester. As a complex mixture, textiles present a challenging pollution issue as breakdown in landfill results in microplastics entering water and soil environments, and incineration results in particulate air pollution. Here the use of edible fungi as bioremediation agents of waste textiles is described for the first time. Three species of filamentous fungi were shown to colonise and grow on mixed fibre textile waste (underpants made from 28% cotton: 68% bamboo viscose: 4% elastane). All three fungi were able to metabolise the common textile dye Reactive Black 5 to some extent. The metabolome was captured to elucidate the dye remediation pathway utilized and to characterise the volatiles released during bioremediation with a view to assessing the safety profile of this process for future industrial applications. The results suggest that edible fungi may be cultivated on textiles, and that some interesting and useful compounds may be produced in the process. This has great biotechnological potential. No mushrooms were produced in this study, suggesting that further work will be needed to optimise conditions for crop production from waste textiles.

Decolorization of various dyes by microorganisms and green-synthesized nanoparticles: current and future perspective

Various types of colored pigments have been recovered naturally from biological sources including shells, flowers, insects, and so on in the past. At present, such natural colored substances (dyes) are replaced by manmade dyes. On the other hand, due to their continuous usage in various purpose, these artificial dyes or colored substances persist in the environmental surroundings. For example, industrial wastewater contains diverse pollutant substances including dyes. Several of these (artificial dyes) were found to be toxic to living organisms. In recent times, microbial-based removal of dye(s) has gained more attention. These methods were relatively inexpensive for eliminating such contaminants in the environmental system. Hence, various researchers were isolated microbes from environmental samples having the capability of decolorizing synthetic dyes from industrial wastewater. Furthermore, the microorganisms which are genetically engineered found higher degradative/decolorize capacity to target compounds in the natural environs. Very few reviews are available on specific dye treatment either by chemical treatments or by bacteria and/or fungal treatments. Here, we have enlightened literature reports on the removal of different dyes in microbes like bacteria (including anaerobic and aerobic), fungi, GEM, and microbial enzymes and also green-synthesized nanoparticles. This up-to-date literature survey will help environmental managements to co-up such contaminates in nature and will help in the decolorization of dyes.

Evaluation of azo dyes degradation potential of fungal strains and their role in wastewater treatment

In the present investigation, two fungal strains were exploited to evaluate their degradation capability on Synozol Red, Yellow, and Navy-Blue dyes which gave the utmost decolorization such as 40%, 70%, 90% by Aspergillus niger, and 36%, 73%, 87% by Trichoderma viride, respectively for 60 days. The Gas Chromatography-Mass Spectrometry (GC-MS) analysis of the decolorized dyes suggested that various compounds such as Caprolactam, Furazan-3-carboxamide, oxime, 4-amino-N, N-dimethyl, 6H-Pyrazolo[1,2-a] [1,2,4,5]tetrazine, Hexahydro-2,3-dimethyl, Benzene, 1-propenyl, Dihydroxymaleic acid, Arsenous acid, tris(trimethylsilyl) ester were produced by the fungi which helped in the removal of dyes from the wastewater. The laccase activity of the degraded dyes was proof that both of the strains positively produced the enzyme that helped in the biodegradation of carcinogenic dyes into less harmful products. The A. niger extracted laccase relative activity was 262%, 265%, and 145.7% for Synozol Yellow, Synozol Red, and Navy Blue, respectively. Similarly, laccase, obtained from T. viride, showed relative activity of 187.5% against Synozol Yellow, 215% against Synozol Red, and 202% against Navy Blue. Furthermore, the supernatant extracted from fungi-decolorized wastewater was used to check phytotoxicity on Vigna radiata, which gave excellent results. Both fungal strains, on the basis of their dye degradation potential, can be used to ameliorate wastewater contaminated with azo dyes.

Evaluating the efficacy of wood decay fungi and synthetic fungal consortia for simultaneous decolorization of multiple textile dyes

Wastewater from the textile industry dyeing process containing high loads of synthetic dyes leads to pollution of water with these toxic and genotoxic dyes. Much effort has been put towards developing biological systems to resolve this issue. Mycoremediation is a well-known approach using fungi to remove, degrade, or remediate pollutants and can be applied to decolorize textile dyes in industrial effluent. Fungal strains from four genera of Polyporales, namely Coriolopsis sp. TBRC 2756, Fomitopsis pinicola TBRC-BCC 30881, Rigidoporus vinctus TBRC 6770, and Trametes pocas TBRC-BCC 18705, were studied for decolorization efficiency, and R. vinctus was found to exhibit the greatest activity in removing all seven tested reactive dyes and one acid dye with a decolorization efficiency of 80% or more within 7 days under limited oxygen. This fungus simultaneously degraded multiple dyes in synthetic wastewater as well as industrial effluent from the dyeing process. To enhance the decolorization rate, various fungal consortia were formulated for testing. However, these consortia only trivially improved efficiency compared with using R. vinctus TBRC 6770 alone. Evaluation of R. vinctus TBRC 6770 decolorization ability was further performed in a 15-L bioreactor to test its ability to eliminate multiple dyes from industrial effluent. The fungus took 45 days to adapt to growth in the bioreactor and subsequently reduced dye concentration to less than 10% of the initial concentration. The following six cycles required only 4-7 days to reduce dye concentrations to less than 25%, demonstrating that the system can run efficiently for multiple cycles without the need for extra medium or other carbon sources.

Filamentous Fungi Are Potential Bioremediation Agents of Semi-Synthetic Textile Waste

Textile waste contributes to the pollution of both terrestrial and aquatic ecosystems. While natural textile fibres are known to be biodegraded by microbes, the vast majority of textiles now contain a mixture of processed plant-derived polymers and synthetic materials generated from petroleum and are commonly dyed with azo dyes. This presents a complex recycling problem as the separation of threads and removal of dye are challenging and costly. As a result, the majority of textile waste is sent to landfill or incinerated. This project sought to assess the potential of fungal bioremediation of textile-based dye as a step towards sustainable and environmentally-friendly means of disposal of textile waste. Successful development of an agar-independent microcosm enabled the assessment of the ability of two fungal species to grow on a range of textiles containing an increasing percentage of elastane. The white rot fungus Hypholoma fasciculare was shown to grow well on semi-synthetic textiles, and for the first time, bioremediation of dye from textiles was demonstrated. Volatile analysis enabled preliminary assessment of the safety profile of this process and showed that industrial scale-up may require consideration of volatile capture in the design process. This study is the first to address the potential of fungi as bioremediation agents for solid textile waste, and the results suggest this is an avenue worthy of further exploration.