Optimization of xylanase production from Enterobacter asburiae PQ396173for hydrolysis of sugarcane bagasse

This work aimed to isolate efficient microbial strains from Similipal Biosphere Reserve to produce xylanase enzyme and use it for the hydrolysis of sugarcane bagasse. Enzymatic assay for the xylanase activity was evidenced from the most potent bacterial strain SSXB1, and it was shown that in unoptimized conditions, SSXB1 showed the highest enzyme activity of 191.86 U/ml/min. In this work, the Box-Behnken design of response surface methodology was employed to optimize the culture conditions for the maximum production of xylanase from SSXB1. In an optimized condition i.e., temperature 35.0℃, pH 7.5, xylan conc. 0.15% and incubation time 36h, the enzyme activity was shown to reach 578.13 U/ml/min. The bacterial strain SSXB1 was identified as Enterobacter asburiae PQ396173 using biochemical and molecular methods. Further enzymatic hydrolysis of sodium carbonate pretreated sugarcane bagasse was optimized using E. asburiae PQ396173 xylanases that showed a good amount of reducing sugar liberation from pretreated biomass under optimized conditions. Additionally, scanning electron microscopy (SEM) analysis of untreated, sodium carbonate pretreated, commercial enzyme (BG-xylan) pretreated, and E. asburiae PQ396173 xylanase pretreated sugarcane bagasse revealed structural alterations in the pretreated biomass. This study is the first ever report about the production of xylanase from E. asburiae PQ396173.