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Lignocellulosic Biomass Wastes to Bioenergy
Published in Amit Kumar, Chhotu Ram, Nanobiotechnology for Green Environment, 2021
Amit Kumar, Diwakar Aggarwal, Amit Kumar Bharti, Chhotu Ram
Lignin degradation is performed by white-rot fungi most effectively. Lignin peroxidases, manganese peroxidizes, and laccases are the major lignin-degrading enzymes that are produced by these fungi. The characteristics of these enzymes vary according to the microbial source. Lignin peroxidase is also known as ligninase. It is one of the most important enzymes involved in the degradation of lignin. Lignin peroxidase has high redox potential (700–1,400 mV) and it can degrade the compounds with high redox potential that are not oxidized by other enzymes. Lignin peroxide can oxidize both phenolic and non-phenolic compounds. It can cleave the recalcitrant non-phenolic units that comprise approximately 90% of lignin (Niladevi, 2009; Plácido and Capareda, 2015). Manganese peroxidase is another important enzyme produced by the lignin-degrading fungi. It is also a heme peroxidase and requires H2O2 for its activity. Manganese peroxidase has lower redox potential lignin peroxidase and generally, it does not oxidize non-phenolic lignin compounds. They are glycoproteins with a molecular weight between 38 and 62.5 kDa (Niladevi, 2009; Plácido and Capareda, 2015). Laccases are the multicopper oxidase enzyme, widely distributed in plants, fungi, and bacteria and have the ability to catalyze the oxidation of various phenolic and non-phenolic compounds as well as many environmental pollutants (Dwivedi et al., 2011).
Fungi Treatment of Synthetic Dyes by Using Agro-industrial Waste
Published in Ram Chandra, R.C. Sobti, Microbes for Sustainable Development and Bioremediation, 2019
Yago Araújo Vieira, Débora Vilar, Ianny Andrade Cruz, Diego Batista Menezes, Clara Dourado Fernandes, Nádia Hortense Torres, Silvia Maria Egues, Ranyere Lucena de Sousa, Luiz Fernando Romanholo Ferreira, Ram Naresh Bharagava
It is important to note that some of the agro-industrial effluents used in the research by Wehaidy et al. (2018) did not present satisfactory results regarding the fungi growth tested, as the saw dust and the orange and tangerine peels. In addition, remarkable attention is paid to the Cooper effect on process optimization; since laccase is also called “multicopper” oxidase, it directly uses the redox capacity of cupric ions, catalyzing various aromatic compounds oxidation and forming, at the end, water and oxygen molecules (Du et al. 2018).
Immobilization of Biocatalysts onto Nanosupports: Advantages for Green Technologies
Published in Grunwald Peter, Biocatalysis and Nanotechnology, 2017
Alan S. Campbell, Andrew J. Maloney, Chenbo Dong, Cerasela Z. Dinu
As for enzymes in wastewater treatment, laccase-based nanoconjugates have been introduced as candidates for the elimination of recalcitrant pollutants (Corvini and Shahgaldian, 2010). Laccase is a multicopper oxidase capable of effectively inducing polymerization and precipitation of such pollutants as an alternative to peroxidases, if enzyme retention and operational stability can be increased. To that end, Hommes et al. reported the enhanced activity and stability of laccase as a result of sorption onto fumed silica nanoparticles. These conjugates exhibited drastically increased catalytic activity retained over time with roughly 80% residual activity under operationally relevant conditions for one week, whereas free enzyme lost all activity after only 1.5 days (Hommes et al., 2012). Laccase is also a highly relevant chemical in the textile industry, aiding in bleaching processes, and in the treatment of effluent in the pulp and paper industry (Kirk et al. (2002). Similar to laccase utilization in wastewater remediation, immobilization using nanomaterials has been shown to improve recovery and thus allow for economic feasibility when its implementation is considered while also maintaining its operational capabilities (Niladevi and Prema, 2008; Bayramoglu et al., 2010). One of the largest applications of enzymes in industry is as additives in detergents; however, wash conditions can be highly oxidizing and most detergents contain various components detrimental to enzyme performance (Es et al., 2015). Again, immobilization onto prefabricated nanosupports has proven beneficial to the operational performance of target enzymes in this application. In a characteristic study, Soleimani et al. showed that adsorption of the detergent additive a-amylase onto silica nanoparticles not only increased enzyme storage stability, but also improved the starch soil cleaning efficiency of a detergent containing the conjugates whereas addition of free enzyme had little effect (Soleimani et al., 2012).
Insights into the catalytic mechanism of ligninolytic peroxidase and laccase in lignin degradation
Published in Bioremediation Journal, 2022
Pankaj Bhatt, Meena Tiwari, Prasoon Parmarick, Kalpana Bhatt, Saurabh Gangola, Muhammad Adnan, Yashpal Singh, Muhammad Bilal, Shakeel Ahmed, Shaohua Chen
The mutation on the active site of the enzyme confirmed the possibility of lignin biodegradation, after docking, we confirmed our findings. Before docking the active site of Laccase contains the His111, Ala80, Ser113, Phe448 (Figure S6). We replaced amino acids His111 and Ala80 with aspartate (negative charged) and serine(non-polar), respectively. It was observed that binding energy and enzyme affinity are not changed, which suggested mutation would be disadvantageous for lignin biodegradation. Further analysis of mutation with different amino acids may provide more beneficial results. Here we have selected only one mutation so other amino acid replacement might be given (may provide) better results (Table ST7). Laccase belongs to multicopper oxidase family, present in microbes and plants. In microbes, it was acting on lignin degradation, whereas in plants, its function in lignin biosynthesis. Molecular docking experiments confirm the various active site amino acids that playing a direct role in lignin degradation. In the present study, the amino acid present in docking site of enzymeversatile peroxidase (P.eryngii) were Ala296, Thr323, Ser188, Asp318, Pro326, Ser324 (Figure S6).The actual hydrogen bond was formed with Ala 296, Thr 323, Ser188, of versatile peroxidase and substrate lignin.