Optimization of xylanase production by Bacillus sp. MCC2212 under solid-state fermentation using response surface methodology

Abstract

Xylanases have become increasingly significant due to their versatile applications in the food, paper, and pharmaceutical industries. Nevertheless, the current production of these enzymes relies on costly substrates, with estimates indicating that over 30% of the production expenses are attributed to these substrates. The objective of this study is to optimize the physico-chemical parameters for obtaining the maximum production of xylanase enzyme from Bacillus sp. MCC2212. The production conditions were statistically optimized using Plackett-Burman design (PBD) and Central Composite design (CCD). The significant variables identified through PB design including temperature, substrate to moisture ratio, MgSO4, peptone, tween 20, inoculum size, inoculum age, incubation time, and extracted xylan, were further optimized using the CCD approach. This optimization process revealed the most influential factors affecting xylanase production, with optimal conditions observed at a temperature, 35 °C; a substrate to moisture ratio, 1:1.75 g:mL; MgSO4, 1.1%; peptone, 1.5%; tween 20, 1.25%; inoculum size, 10 % (v/w); inoculum age, 20 h; an incubation time, 50 h; and crude xylan extracted from wheat bran at a concentration of 6% v/w. The R2 value of the model was found to be 0.9901, indicating its effectiveness. The optimized CCD model displayed a 1.84-fold greater xylanase production than the PB design approach. These findings suggest that wheat bran, a readily available agro-waste, could be a feasible alternative to the conventional substrate, beechwood xylan, for the production of xylanase enzyme with the possibility of achieving higher production levels optimized by using statistical design approach.