Extracellular secretion of lignocellulolytic enzymes by diversewhite rot asidiomycetes fungi

Abstract

Rich source of biota includes several white rot fungi, were reported in Western Ghats regions of Tamil Nadu, India. The effective identification of white rot fungi and their lignocellulolytic enzymes play a crucial role for degradation of agricultural and industrial wastes to maintain su sta ina ble ecosystem. T hus, the present study was conducted to assess the secretion of lignocellulolytic enzymes of diverse white rot fungi, collected from Western Ghats regions of Tamil Nadu, comprising of Kotagiri and Ooty of the Nilgiri district, Siruvani and Anaikati of Coimbatore district. A total of 16 white rot fungi belonging to 6 genera, viz., Pleurotus spp., Lentinus spp., Ganoderma spp., Trametes spp., Pycnoporus spp. and Schizophyllum spp. were collected and identified through morphological and molecular methods. The activity of cellulase enzyme was prominently visible in Pleurotus pulmonarius, P. sajar-caju, Pycnoporus sanguineus, P. ostreatus, Ganoderma gibbosum and Schizophyllum commune and hemicellulolytic activity was maximum in Trametes ijubarskii, Lentinus crinitus, P. sanguineus and G. gibbosum . The quantitative and qualitative screening for major lignolytic enzymes, viz., laccase (Lac), lignin peroxidase (LiP) and manganese peroxidase (MnP) revealed significant levels of Lac secretion when compared to LiP and MnP by P. pulmonarius, P. sajar-caju and Schizophyllum commune. The syringaldazine well test further confirmed the secretion of laccase as major enzyme followed by LiP and MnP. Also the Lac and LiP activity was maximum at pH of 4.5 and MnP activity at pH of 5.0 by P. pulmonarius, P. sajar caju and S. commune. Temperature of 30°C induced maximum secretion of Lac, LiP and MnP by these three fungi. A significant level of Lac was observed on 4 th day after inoculation while LiP and MnP was maximum on 7 th and 8 th day for P. pulmonarius and P. sajar-caju. Whereas, S. commune secreted significant levels of Lac on 10 th to 11 th da y, while LiP and MnP on 6 th and 7 th da y. This study paves the way for u se of P. pulmonarius, P. sajar-caju and S. commune for biodegradation and bioconversion of agrowastes.

Bioprospecting White-Rot Basidiomycete Irpex lacteus for Improved Extraction of Lignocellulose-Degrading Enzymes and Their Further Application

“…The enzyme cocktail that was obtained after 4 days of fungal growth on hay as a carbon source, in subsequent hay hydrolysis demonstrated 63% conversion rate into reducing sugars. These observations to some extent contradict with other studies where white-rot fungi produced the most active enzymes after 12 days of incubation [ 21 ]. The differences could be explained by previous assessment of only individual enzymes or their limited combinations [ 8 , 21 ] or the by more intense binding of the enzyme to carbohydrate source (hay) at later incubation stage and inefficient recovery of that enzyme fraction.…”

“…These observations to some extent contradict with other studies where white-rot fungi produced the most active enzymes after 12 days of incubation [ 21 ]. The differences could be explained by previous assessment of only individual enzymes or their limited combinations [ 8 , 21 ] or the by more intense binding of the enzyme to carbohydrate source (hay) at later incubation stage and inefficient recovery of that enzyme fraction. In this study, the performance of the whole crude enzyme cocktail without purification and removal of any specific protein fraction was assessed.…”

Isolation of Fungi from a Textile Industry Effluent and the Screening of Their Potential to Degrade Industrial Dyes

“…Our results coincide with reports of compounds derived from agro-industrial residues, such as wheat straw, rice straw, corn stubble, and cane bagasse, functioning as inducers of the main lignin-modifying enzymes in white rot fungi [64][65][66]. Furthermore, the addition of dyes had a clear induction effect on enzymatic activity [67,68].…”

Regulation of dye-decolorizing peroxidase gene expression in Pleurotus ostreatus grown on glycerol as the carbon source

“…In contrast to the findings presented here, they did not observe the significant influence of glucose or glycerol on laccase production. Various reports have indicated that the production of LMEs in basidiomycetes is dependent on the carbon and nitrogen sources used, as well as the presence of aromatic compounds in the culture medium ( Elisashvili, Kachlishvili & Asatiani, 2018 ; Stajić et al, 2006 ; Thiribhuvanamala et al, 2017 ). For instance, Elisashvili et al (2002) demonstrated the effect of different carbon sources and aromatic compounds on the lignocellulolytic enzyme activity of different edible and medicinal basidiomycetes, concluding that it is possible not only to increase lignocellulolytic activity substantially, but also to trigger their preferential synthesis by supplementing the culture medium with nutritional compounds.…”