Production of Lignocellulolytic Enzymes by Microorganisms Isolated from Bulbitermes sp. Termite Gut in Solid-State Fermentation

Abstract

Significant amounts of lignocellulosic waste biomass are produced annually. Lignocellulose degrading enzymes play a crucial role in converting the woody materials into sugars and biofuels. The aims of this work were to isolate and characterise the microorganisms from Bulbitermes sp. termite gut with the ability to produce lignocellulolytic enzymes by using forest residues of saw dust as substrate in solid-state fermentation system. Four of the microorganisms (A1, B1, B2, and Br3) with highest lignocellulolytic enzyme activity, which identified as Aspergillus sp., Bacillus sp., Bacillus sp. and Brevibacillus sp., respectively, were selected for characterization. Aspergillus sp. A1 showed highest activities of lignin peroxidase (729.12 U/g) and β-glucosidase (22.97 U/g). Highest activity of endoglucanase (138.77 U/g) and manganese peroxidase (47.73 U/g) were observed in Bacillus sp. B1. The Bacillus sp. B2 produced highest activities of exoglucanase (32.16 U/g) and laccase (71.18 U/g). The highest xylanase (104.96 U/g) activity was observed in Brevibacillus sp. Br3. The production of enzymes particularly for endoglucanase, β-glucosidase, xylanase, lignin peroxidase and laccase were approximate 17–93 % higher in co-culture compared to single culture. The findings suggested that saw dust can be used as a cheap renewable raw material for production of lignocellulolytic enzymes. The present study also indicates that the fungal-bacterial co-culture could be a good alternative for the enzymes production.