Optimization of high endoglucanase yields production from polypore fungus, Microporus xanthopus strain KA038 under solid-state fermentation using green tea waste.

Kim Anh Nguyen,Jaturong Kumla,Watsana Penkhrue,Nakarin Suwannarach,Saisamorn Lumyong

doi:10.1242/bio.047183

Kim Anh Nguyen, Jaturong Kumla + Show 3 more

Open Access

https://doi.org/10.1242/bio.047183

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Abstract

ABSTRACTPolypores are diverse macrofungi that have been extensively studied for their lignocellulolytic enzyme production capabilities. Currently, these enzymes are being used for many industrial purposes. However, the high cost associated with their production is the main barrier to their broader application. This work aimed to study the optimal medium and conditions for endoglucanase production using solid state fermentation. Seven polypore strains were used for endoglucanase activity screening. The fermentation experiments were carried out in 250 ml Erlenmeyer flasks with green tea waste as a substrate. Notably, Microporus xanthopus strain KA038 showed the best level of activity (38.62 IU/gds). Various parameters such as moisture content, nitrogen source, initial pH value, inoculum size and incubation time were considered to determine the optimal conditions for endoglucanase production. The optimal medium consisted of green tea leaves as a carbon source, beef extract as an organic nitrogen source, NH4H2PO4 as an inorganic nitrogen source, pH 7.0 and an incubation temperature at 30°C for 4 days resulted in a high enzyme yield with M. xanthopus strain KA038 (81.8 IU/gds).This article has an associated First Person interview with the first author of the paper.

Highlights

Lignocellulosic biomass is mainly formed of three polymers; cellulose, hemicellulose and lignin along with other components (Isikgor and Becer, 2015)
Five fungal strains were placed into the genus Microporus, within which the strains KA007, KA009, KA012 and KA016 were identified as Microporus affinis and the strain KA038 was Microporus xanthopus
The remaining fungal strain, KA053, was placed in the genus Favolus, which forms a sister taxon to Favolus grammocephalus and Favolus emerici

Summary

Introduction

Lignocellulosic biomass is mainly formed of three polymers; cellulose, hemicellulose and lignin along with other components (Isikgor and Becer, 2015). Lignocellulose biomass is a source material that has been used in previous decades in the production of bioethanol, organic acids, enzymes and biodegradable plastics in the form of cheap carbohydrates (Ravindran and Jaiswal, 2016). Lignocellulosic material is promising as an energy source because of its potential for lowcost fermentation (Sherief et al, 2010). A substantial amount of tea waste is left after the tea extraction process. Looking elsewhere to minimize or eliminate tea waste has been a difficult task in the tea processing industry (Yang et al, 2015). At present, the elimination of tea waste in the environment in an economically sound and efficient manner has become of significant interest among scientists

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