Hydrolysis of bamboo cellulose and cellulase characteristics by Streptomyces griseoaurantiacus ZQBC691

Abstract

This investigation studies the cellulolytic characteristics of a microbial isolate native to Taiwan. The bacterium was isolated from a compost of bamboo shoots in Taiwan and identified as Streptomyces griseoaurantiacus ZQBC691 using morphological criteria and 16S rRNA sequence. The strain ZQBC691 grew vigorously on amorphous cellulose (carboxymethylcellulose – CMC) and produced endoglucanase. Less endoglucanase was produced on crystalline cellulose (avicel). Under the optimal growth condition with a of 5.3, a shaking speed of 150rpm, a culture temperature of 30°C, and a CMC concentration of 15g/L, the final concentration of reducing sugar reached 1.60g/L. Additionally, the strain ZQBC691 can hydrolyze purified bamboo fiber to generate glucose, and ferment monosugars to produce products including lactic acid and acetic acid. Moreover, data obtained in an enzyme activity test indicated that at the optimal temperature of 50°C strain ZQBC691 generated 34.13IU/ml of endoglucanase on CMC, and 37.38IU/ml at the optimal pH of 5.