Isolation and identification of Bacillus sp.: For the isolation of the bacterium Bacillus sp. the waste soil samples were collected using pre-sterilized sample bottles and sterile spatula from different areas of sugar-cane industry. The soil samples were diluted by serial dilution and cultured on xylan agar media. The isolate producing clear transparent zone around the colony on xylan agar plate was selected as xylanolytic bacteria and purified by sub cultured. The identification of Bacillus sp. was confirmed on the basis of morphological and biochemical characteristics using the criteria of Bergey’s Manual of Systematic Bacteriology (Holt et al. 1993). The culture was maintained on wheat bran xylan agar slants by weekly transfers onto fresh slants and was stored at 4oC in refrigerator. Xylanase production and assay: The production of xylanase was carried out using Bacillus sp. cultured in 250 ml Erlenmeyer flasks containing 100 ml of medium [0.5% wheat bran xylan, 0.5% yeast extract, 1% peptone, 0.5% NaCl] at 50?C for 2 days in an incubator on a rotary shaker. After this period of time the culture was centrifuged at 8000 rpm for 15 min at 4?C and the cell free supernatant was used as the crude enzyme preparation. Xylanase was assayed by DNS method (Miller 1959) using wheat bran xylan (1%) as substrate and phosphate buffer at pH 7 and 50?C. One unit of xylanase is defined as the concentration of enzyme that catalyzes the formation of 1 μmole of product (xylose) ml-1min-1 under the assay conditions. The concentration of enzyme in crude biological preparation is expressed as unit/ml (U/ml) or unit/litter (U/L). Cellulase was assayed according to Mandels and Sternburg (1976) using sodium citrate buffer. One unit of cellulase is defined as the amount of the enzyme that liberates 1 μmol reducing sugar as glucose ml-1 min-1 under the assay conditions. The soluble protein content in the crude extract was determined according to Lowry et al (1951) using bovine serum albumin as the standard. Optimization of cultural parameters: In order to get xylanase, the bacterium was grown in the liquid cultural medium. Various physical and nutritional parameters for xylanase production were optimized by maintaining all factors at a constant level except the one being studied. The parameters studied in our laboratory were pH, temperature, carbon and nitrogen sources, % of xylan, incubation period and metal salts. The effect of pH on xylanase production was assessed by cultivating the strain Bacillus sp. in media of varied pH ranging from 5.0-11.0. The influence of temperature on xylanase production was studied by cultivating the strain Bacillus sp. at different temperatures such as 30?C, 40?C, 50?C, 60?C and 65?C. Xylanase production by Bacillus sp. was studied by cultivating the strain in a set of media having different carbon sources such as wheat bran xylan, birch wood xylan, oat spelt xylan, rice bran xylan, glucose, xylose, lactose, cellobiose, cellulose, carboxymethyl cellulose and starch. Xylanase production from Bacillus sp. was also examined in a set of media containing wheat bran xylan with various percentages (0.5%, 1.0%, 2.0%, 3.0% and 4.0%). To select the best nitrogen sources for xylanase production by Bacillus sp., both organic and inorganic nitrogen sources were incorporated separately into the production media. Different nitrogen sources used inIsolation and identification of Bacillus sp.: For the isolation of the bacterium Bacillus sp. the waste soil samples were collected using pre-sterilized sample bottles and sterile spatula from different areas of sugar-cane industry. The soil samples were diluted by serial dilution and cultured on xylan agar media. The isolate producing clear transparent zone around the colony on xylan agar plate was selected as xylanolytic bacteria and purified by sub cultured. The identification of Bacillus sp. was confirmed on the basis of morphological and biochemical characteristics using the criteria of Bergey’s Manual of Systematic Bacteriology (Holt et al. 1993). The culture was maintained on wheat bran xylan agar slants by weekly transfers onto fresh slants and was stored at 4oC in refrigerator. Xylanase production and assay: The production of xylanase was carried out using Bacillus sp. cultured in 250 ml Erlenmeyer flasks containing 100 ml of medium [0.5% wheat bran xylan, 0.5% yeast extract, 1% peptone, 0.5% NaCl] at 50?C for 2 days in an incubator on a rotary shaker. After this period of time the culture was centrifuged at 8000 rpm for 15 min at 4?C and the cell free supernatant was used as the crude enzyme preparation. Xylanase was assayed by DNS method (Miller 1959) using wheat bran xylan (1%) as substrate and phosphate buffer at pH 7 and 50?C. One unit of xylanase is defined as the concentration of enzyme that catalyzes the formation of 1 μmole of product (xylose) ml-1min-1 under the assay conditions. The concentration of enzyme in crude biological preparation is expressed as unit/ml (U/ml) or unit/litter (U/L). Cellulase was assayed according to Mandels and Sternburg (1976) using sodium citrate buffer. One unit of cellulase is defined as the amount of the enzyme that liberates 1 μmol reducing sugar as glucose ml-1 min-1 under the assay conditions. The soluble protein content in the crude extract was determined according to Lowry et al (1951) using bovine serum albumin as the standard. Optimization of cultural parameters: In order to get xylanase, the bacterium was grown in the liquid cultural medium. Various physical and nutritional parameters for xylanase production were optimized by maintaining all factors at a constant level except the one being studied. The parameters studied in our laboratory were pH, temperature, carbon and nitrogen sources, % of xylan, incubation period and metal salts. The effect of pH on xylanase production was assessed by cultivating the strain Bacillus sp. in media of varied pH ranging from 5.0-11.0. The influence of temperature on xylanase production was studied by cultivating the strain Bacillus sp. at different temperatures such as 30?C, 40?C, 50?C, 60?C and 65?C. Xylanase production by Bacillus sp. was studied by cultivating the strain in a set of media having different carbon sources such as wheat bran xylan, birch wood xylan, oat spelt xylan, rice bran xylan, glucose, xylose, lactose, cellobiose, cellulose, carboxymethyl cellulose and starch. Xylanase production from Bacillus sp. was also examined in a set of media containing wheat bran xylan with various percentages (0.5%, 1.0%, 2.0%, 3.0% and 4.0%). To select the best nitrogen sources for xylanase production by Bacillus sp., both organic and inorganic nitrogen sources were incorporated separately into the production media.