Evaluation of 18 isolates of basidiomycetes for Lignocellulose degrading enzymes

Abstract

Since fossil fuel resources are limited there is a necessity to produce alternative types of fuel that are renewable and eco-friendly. Basidiomycetes are potential sources of enzymes that can be used for biofuel production. The current study aimed to isolate basidiomycetes from Sri Lanka, screen them for lignocellulose degrading enzymes, namely cellulase, xylanase, laccase, Mn peroxidase and lignin peroxidase and study the effect of potential inducers of laccase production. Among the eighteen basidiomycetes isolated, Pycnoporus sp. produced the highest cellulase activity (0.23 FPU/ml) whereas Phlebiopsis sp. produced the highest xylanase activity (5.4 U/ml). Earliella scabrosa produced the highest laccase (91.2 U/l) and Mn peroxidase (17.5 U/l) activities. Lignin peroxidase activity was not detected from the isolates. Effect of alkali lignin, Cu 2+ and rice bran, three potential inducers, on laccase production by E. scabrosa, Pycnoporus sp. and Trametes hirsuta (M40) was studied. Results indicated that alkali lignin (2 g/l) significantly increased laccase production from Pycnoporus sp. and T. hirsuta (M40) while Cu 2+ increased laccase production from E. scabrosa and T. hirsuta at 200 µM. Use of rice bran (10 g/l) resulted in higher laccase production from E. scabrosa and Pycnoporus sp. High laccase activity (79600 U/l) was obtained from E. scabrosa by using 50 g/l of rice bran and by extending the incubation period to 18 days. The study concluded that some of the basidiomycetes isolated can produce significant lignocellulose degrading enzyme activities.

Bagasse and vinasse, factory wastes from sugarcane industry as potential substrates for bioethanol production

“…As per the results, E. scabrosa was the most efficient fungal isolate in pretreatment of sugarcane bagasse by performing delignification. In a previous study, the same E. scabrosa isolate showed 0.00912 U/mL laccase activity in glucose containing medium (Kathirgamanathan et al, (2017). The current study confirmed that the addition of sugarcane bagasse has induced the laccase activity of the isolate.…”

“…Ten fungal isolates were evaluated in the current study for their sugarcane bagasse pretreatment and saccharification potential. As previously mentioned, two efficient ligninolytic basidiomycete isolates: E. scabrosa and T. hirsuta (Kathirgamanathan et al, 2017) and eight efficient cellulolytic filamentous fungal isolates which belonged to three main genera, viz. Aspergillus, Trichoderma and Penicillium (Jayasekara et al, 2020) were evaluated.…”

“…Earliella scabrosa (M14) and Trametes hirsuta (M40), the basidiomycetes fungi with higher laccase activities (Kathirgamanathan et al, 2017) isolated from the Knuckles forest region of Sri Lanka were obtained from the previously isolated basidiomycetes collection of the same laboratory where the current study was conducted.…”

Microbial Cellulases: An Overview and Applications

“…However, the three groups of bacteria, namely, actinomycetes, α-proteobacteria, and γ-proteobacteria, are known to have ligninolytic systems. Some actinomycetes were studied for their role in lignin biodegradation [37]. These degraded lignin into low-molecular-weight fragments.…”

“…In a different study, 18 basidiomycete isolates from the natural environment of Sri Lanka has been evaluated for their lignocellulose-degrading enzyme production. An Earliella scabrosa species with higher laccase activity (79,600 U/l) when cultured in 50 g/l rice bran has been reported [37]. Thus, it can potentially be used for industrial production of laccase using rice bran as a cheap carbon source for high laccase production.…”