Crude Xylanases and Pectinases from Bacillus spp. Along with Commercial Cellulase Formulate an Efficient Tailor-Made Cocktail for Sugarcane Bagasse Saccharification

Abstract

Restricted activities of individual plant cell wall–degrading enzymes, i.e., cellulase, xylanase, and pectinase, on plant biomass are due to the complex interactions among structural polysaccharides and lignin components of plant cell wall. This can be overcome through altering the structural components by subjecting biomass to physicochemical pretreatments. In present studies, experiments were undertaken with the rationale that applying tailor-made cocktail formulations to pretreated biomass, by striking a synergy between core cellulolytic (C) and/or accessory xylano-pectinolytic (X, P) enzymes from the Bacillus strains B. safensis M35, B. altitudinis R31 and B. altitudinis J208, should enhance the saccharification. Efficiency of individual and substitutive cocktails for saccharification of raw, NaOH, and NH4OH pretreated sugarcane bagasse was demonstrated and compared. Among the individual CP, CX, PX, and CPX cocktails, the CPX cocktails yielded enhanced and maximum saccharification of 71.4–81.3% and 17.0–17.28% from NaOH and NH4OH pretreated biomass as compared to the 7.1–7.6% from raw. After finding xylanases and pectinases from the three Bacillus strains compatible with each other, substitutive cocktail CPXsub was prepared by putting all these accessory enzymes with core cellulase. This enhanced saccharification to 84.02% and 25.52% from NaOH and NH4OH pretreated biomass as compared to 8.91% from raw. With the support of HPLC, FTIR, and SEM analyses, results clearly confirmed the high saccharifying potential of tailor-made substitutive cocktails due to synergistic and accessory nature of xylanases and pectinases to the core commercial cellulase.