Production, Characterization and Purification of Xylanase From Staphylococcus aureus Mbxi-K4

Abstract

Pollard is a by-product from dry milling wheat into flour and contains 16,49% of crude fiber. The addition of xylanase in wheat-pollard diet is necessary to reduce viscosity of digesta. Thus could be easily absorbed in intestinal gut. The objectives of this research are to produce xylanase in batch system bioreactor, to characterize and purify xylanase from Staphylococcus aureus MBXi-K4. Maximum enzyme production was reached after 72 hours of cultivation with specific enzyme activity of 10,5 U/mg protein. Biomass specific growth rate (μ) was 0,107 per hour, yield of product of 2,255 (g product/g substrate). The optimum temperature and pH was 70oC and 6 respectively. The xylanase maintained its stability for 30 minutes at 70oC and over pH range 4 – 8. The Km and Vmax value at 70oC on oatspelt xylan was 1,086 (mg/ml) and 3,195 (μmol xilose/min.ml) respectively. Xylanase was purified from the culture supernatant of S.aureus MBXi-K4. The purity of xylanase increased 11,69 fold than those of the crude enzyme. The specific activity after purification was 383,9 U/mg. Three kinds of xylanase activities was visualized by zymogram technique with estimated molecular weights of 45,6 kDa, 28,1 kDa and 21,6 kDa. The purified xylanase had one band protein with molecular weight of 47,9 kDa. Xylanase from S.aureus MBXi-K4 is a moderate thermostable enzyme and a good candidate as feed additive on feed industry with an improvement on its productivity and thermo stability.