Abstract:
Study on the optimum condition for production of xylanase from alkaliphilic Bacillusfirmus K- 1, isolated from a waste water treatment plant of Bang-pa-in paper industry at Ayuttaya.province, in shake flask was performed. It was found that 1.00% of corn hull was the bestcarbon source for production of xylanase when compared with rice bran and the otheragricultural residues such as rice straw, corn cob and sugarcane bagasse. The SDS-PAGE ofculture supernatant showed that protein which was induced from corn hull, had three moreprotein bands (49, 39 and 33 kDa) than those from the other carbon sources. These proteinsbands might be xylanolytic enzymes because it had the highest xylanase activity. The bestnitrogen source was 0.40% urea when compared with ammonium nitrate, ammonium sulfate,sodium nitrate and potassium nitrate. When the bacterium was grown in the mineral saltmedium using 1.00% of corn hull and 0.40% of urea as carbon source and nitrogen source,respectively. It gave 1.60 Ulml xylanase activity. The various concentrations of mineral saltssuch as CaCl,, FeSO,, MgSO,, MnSo,, CdSO,, CoSO, and ZnC1, had no effect on xylanaseproduction.The production of xylanase from Bacillus firmus K-1 was performed in a literfermentor with working volume 0.50 liter using 1.00% of corn hull and 0.40% urea as carbonand nitrogen source, respectively. The experiment showed that the production of xylanase wasfound to increase along with the cell growth. The xylanase activity increased when reducingsugar decreased under aeration treatment. The xylanase activity also increased when agitationspeed was increased from 250-400 rpm. In addition, when aeration rate was increased from 0.25to 1.25 wm, it was found that 1.00 wm at 400 rpm gave the highest xylanase activity.