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Role of Enzymes in Bioremediation of Organic Pollutants
Published in M.H. Fulekar, Bhawana Pathak, Bioremediation Technology, 2020
Smita Chaudhry, Rashmi Paliwal
Peroxidases are heme-containing enzymes and are ubiquitously distributed among the microorganisms, as well as plants. Plant peroxidases are considered multifunctional enzymes responsible for lignification and crosslinking of biopolymers in the cell wall, thus building the defense system in plants. Peroxidases are also induced and expressed in certain plant tissues catalyzing the oxidation of aromatic substrates using hydrogen peroxidase as the cosubstrate. Peroxidases on the basis of preferred substrates include different classes such as lignin peroxidase (LiP), manganese-dependent peroxidase (MnP), and versatile peroxidase (VP). These enzymes have been reported to possess high potential to degrade toxic substances in nature (Karigar and Rao, 2011).
Role of Enzymes in the Bioremediation of Refractory Pollutants
Published in Maulin P. Shah, Removal of Refractory Pollutants from Wastewater Treatment Plants, 2021
Viresh R. Thamke, Ashvini U. Chaudhari, Kisan M. Kodam, Jyoti P. Jadhav
Versatile peroxidase (VP) has broad substrate specificity and the ability to oxidize the substrate in the absence of manganese (Karigar and Rao 2011). VP combines the substrate specificity characteristics of the three other fungal peroxidase families. In this way, it is able to oxidize a variety of (high and low redox potential) substrates including Mn2+, phenolic and non-phenolic lignin dimers, a-keto-g-thiomethylbutyric acid, veratryl alcohol, dimethoxybenzenes, different types of dyes, substituted phenols, and hydroquinones. VP has been found to be present in species of Pleurotus and Bjerkandera, and is able to oxidize both phenolic and nonphenolic compounds including dyes (Mester and Field 1998; Ruiz-dueñas et al. 1999).
Impact of nanomaterials accumulation on the organic carbon associated enzymatic activities in soil
Published in Soil and Sediment Contamination: An International Journal, 2023
Gyan Datta Tripathi, Zoya Javed, Meghana Gattupalli, Kavya Dashora
Enzymes play a very important role in lignin degradation and divided into two main groups: Lignin modifying enzyme (LME), phenol oxidase (laccases) and heme containing peroxidases (POD), particularly lignin, manganese, and multifunctional (versatile) peroxidase, are two types of LME generated by bacteria and the next is lignin degrading auxiliary (LDA) are unable to breakdown lignin on their own (da Silva Coelho-Moreira et al. 2013). Lignin peroxidase (LiP, EC 1.11.1.14) is a glycosylated enzyme that uses hydrogen peroxide (H2O2) to catalyze the oxidation of non-phenolic lignin units and mineralize resistant aromatic chemicals. Lignin oxidation occurs through electron transfer, non-catalytic bond cleavages, and aromatic ring opening (Choinowski, T et al. 1999). . During the early phases of lignin breakdown, the enzyme Manganese peroxidase (MnP,EC 1.11.1.13) plays a critical role (Perez, J et al. 1990).Due to its larger redox potential, MnP promotes more phenolic lignin breakdown than laccase, resulting in the release of carbon dioxide (Ten Have, R., & Teunissen, P. J. 2001). Versatile Peroxidase (VP, EC 1.11.1.16) as the name implies, versatile peroxidase has both LiP and MnP catalytic capabilities. VP was originally extracted from the Bjerkandera fungi, and it was discovered that it could alter lignin without the use of an external mediator (Moreira, P. R et al.2007).
Development of a magnetically separable co-immobilized laccase and versatile peroxidase system for the conversion of lignocellulosic biomass to vanillin
Published in Journal of the Air & Waste Management Association, 2020
Kongkona Saikia, Dhanya Vishnu, Abiram Karanam Rathankumar, Balakumaran Palanisamy Athiyaman, Ramón Alberto Batista-García, Jorge Luis Folch-Mallol, Hubert Cabana, Vaidyanathan Vinoth Kumar
Further, on comparing the yield of vanillin with free laccase and free peroxidase under the same reaction condition of the co-immobilized biocatalytic system, it was observed that the vanillin yield was, respectively, 1.1-fold and 1-fold lower than the co-immobilized system. Although laccase has the ability for depolymerization of phenolic compounds, in the presence of a radical mediator, it cannot act on non-phenolic compounds alone. On the other hand, versatile peroxidase oxidizes lignin at phenolic and non-phenolic aryl-ether positions (Crestini, Melone, and Saladino 2011; Vishnu et al. 2017). This explains the lowered vanillin yield in the individual laccase and peroxidase system when compared to the co-immobilized biocatalytic system. Another advantage of the co-immobilized system is that laccase and versatile peroxidase can constitute oxidative processes over a wide range of pH and have low substrate specificity (Crestini, Melone, and Saladino 2011). Subsequently, on analyzing the individual immobilized laccase and peroxidase system under the same reaction conditions of the co-immobilized system, there was a 1.16-fold and 1.08-fold reduction in vanillin yield in the immobilized laccase and peroxidase system, respectively, when compared to the co-immobilized system. This increase in the vanillin yield in the co-immobilized biocatalytic system can be attributed to the synergistic effect of laccase and versatile peroxidase which induced the depolymerization of phenolic and non-phenolic compounds of lignin for the enhanced production of vanillin (Vishnu et al. 2017).