Application of crude xylanolytic and pectinolytic enzymes in diverse industrial processes make these enzymes commercially valuable and demand their production process to be cost-effective. Out of four different agrowaste biomass, wheat bran (WB) and citrus peel (CP), when amended as fermentation substrates, respectively induced the highest xylanolytic enzymes and pectinolytic enzymes from both, B. safensis M35 and B. altitudinis J208. Further, the simultaneous amendment of WB and CP yielded concurrent production of these cellulase free xylanolytic and pectinolytic enzymes. Hence, the quadratic model was developed using the Central Composite Design of Response Surface Method (CCD-RSM). The model gave the concentration values for WB and CP substrates to be amended in one single production medium for obtaining two optimized predicted response values of xylanase activity and pectinase activity units, which were further practically validated for the xylanase and pectinase production responses from the optimized production medium (OPM). These practically obtained response values from OPM were found to be in accordance with a range of 95% predicted intervals (PI) values. These observations verified the validity of the predicted quadratic model from RSM and suggested that both xylanase and pectinase enzymes can be induced concurrently from both of the bacterial strains. Xylanases and pectinases are the commercially important industrial groups of enzymes, members of which exhibit diverse xylanolytic and pectinolytic enzymatic activities. These groups of enzymes harbor a huge commercial potential as their biotechnological applications span broad spectra in diverse industries such as biofuels, pulp-paper, food, animal feed, textile, fiber, etc. Out of these, biofuel industries demand these xylanolytic and pectinolytic enzymes play their accessory role to the core cellulase enzymes for improving plant biomass saccharification. Whereas, animal feed industries require combination of cellulase, xylanase and or pectinase for improving the nutrition quality of grain and feed. On the other hand, pulp and paper as well as textile industries need the cellulase free xylanase and pectinase enzymes for their respective applications, i.e., to prepare hemicellulose free cellulose papers, to remove pectin (rhamnogalacturonan) coating from cotton and denim fibers, Food and beverage industries also need xylanase and pectinase enzymes to clarify pectin polymeric fraction from fruit juices and to improve the tea flavor 1,2. These applications append the worth to the organisms which can produce the xylanase and pectinase enzymes and the cellulase free nature of such enzymes is an add-on benefit to this.

After chemical pretreatment, improved amenability of agrowaste biomass for enzymatic saccharification needs an understanding of the effect exerted by pretreatments on biomass for enzymatic deconstruction. In present studies, NaOH, NH4OH and H2SO4 pretreatments effectively changed visible morphology imparting distinct fibrous appearance to sugarcane bagasse (SCB). Filtrate analysis after NaOH, NH4OH and H2SO4 pretreatments yielded release of soluble reducing sugars (SRS) in range of ~0.17–0.44%, ~0.38–0.75% and ~2.9–8.4% respectively. Gravimetric analysis of pretreated SCB (PSCB) biomass also revealed dry weight loss in range of ~25.8–44.8%, ~11.1–16.0% and ~28.3–38.0% by the three pretreatments in the same order. Release of soluble components other than SRS, majorly reported to be soluble lignins, were observed highest for NaOH followed by H2SO4 and NH4OH pretreatments. Decrease or absence of peaks attributed to lignin and loosened fibrous appearance of biomass during FTIR and SEM studies respectively further corroborated with our observations of lignin removal. Application of commercial cellulase increased raw SCB saccharification from 1.93% to 38.84%, 25.56% and 9.61% after NaOH, H2SO4 and NH4OH pretreatments. Structural changes brought by cell wall degrading enzymes were first time shown visually confirming the cell wall disintegration under brightfield, darkfield and fluorescence microscopy. The microscopic evidence and saccharification results proved that the chemical treatment valorized the SCB by making it amenable for enzymatic saccharification.

The uncontrolled use of fossil fuels and concerns about its future availability, have invoked interest over unconventional alternative energy sources like solar, hydropower, geothermal, nuclear and biomass. Plants, being largest renewable biomass on earth, have received consideration as a source of biofuels. Ruminant dung isolates M35, R31 and J208 belonging to Bacillus sp. produces majorly endo-xylanase when induced with wheat bran. Such plant cell wall degrading endo-xylanases with broad pH optima and mesophilic nature can act as accessory enzymes with cellulases to enhance the saccharification of plant biomass in biofuel industries.

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