Improved xylanase production from a haloalkalophilic Staphylococcus sp SG-13 using inexpensive agricultural residues

The production of an alkali-stable xylanase, with dual pH optima, from haloalkalophilic Staphylococcus sp. SG-13 has been enhanced using agro-residues in submerged fermentation and a biphasic growth system. The agro-residues such as wheat bran, sugarcane bagasse, corncobs and poplar wood when used as sole carbon source, improved the xylanase yield by five-fold as compared to xylose and xylan. Staphylococcus sp. SG-13 also produced equally good amounts of xylanase when grown simply in deionized water (pH 8.0) supplemented with agro-residues as sole carbon source. In the biphasic growth system (lower layer containing agricultural residue set in agar medium with liquid medium above it), the prime substrate, wheat bran (1% w/v), resulted in maximum xylanase production of 4525 U l(-1) (pH 7.5) and 4540 U l(-1) (pH 9.2) at an agar: broth ratio of 4.0 after 48 h of incubation at 37 degreesC under static conditions. In general, the cost-effective agro-residues were found to be more suitable inducers for xylanase production over expensive substrates like xylan.