A comparative study of Cellulomonas sp. and Bacillus sp. in utilizing lignocellulosic biomass as feedstocks for...

The demand for enzymes is increasing continuously due to their applications in various avenues. The pectin-hydrolyzing bacteria, Cellulomonas sp. and Bacillus sp., isolated from forest soil have the potential to produce industrially important enzymes (pectinase, PGase, Cellulase, and xylanase). However, these bacteria have different optimal cultural conditions for pectinase production. The optimal cultural conditions for Cellulomonas sp. were room temperature (25-26℃), pH 7, 1% inoculum volume, and 1.5% citrus pectin with 8.82 ± 0.92 U/mL pectinase activity. And Bacillus sp. illustrated the highest pectinase activity (12.35 ± 0.72 U/mL) at room temperature, pH 10, 1% inoculum volume, and 1.5% pectin concentration. Among the different agro-wastes, the orange peel was found to be the best substrate for pectinase, PGase, and cellulase activity whereas barley straw for xylanase activity. Further, Cellulomonas sp. and Bacillus sp. illustrated higher pectinase activity from commercial pectin compared to orange peel showing their preference for commercial citrus pectin. In addition, the optimization by the Box-Behnken design increased pectinase activity for Cellulomonas sp., while a noticeable increase in activity was not observed in Bacillus sp. Besides, all the agro-wastes exploited in this study can be used for pectinase, PGase, and xylanase production but not cellulase. The study revealed that each bacteria has its specific optimal conditions and there is a variation in the capacity of utilizing the various lignocellulosic biomass.