Xylanase Production by Streptomyces Lividans (NRC) and Itʹs Application on Waste Paper

The ability of different Streptomyces strains to degrade the lignocellulosic materials to produce many useful products such as xylanase, reducing sugar and microbial proteins were studied. Wheat straw and corn cobs were used as substrates in liquid medium for enzymes and protein production. Four types of Streptomyces strains were screened for enzyme and protein content. Streptomyces lividans was the most active and producer strains on the static cultured using xylan or wheat straw as the best substrate for enzyme production. The optimum conditions for enzyme production were studied. Maximum level of xylanase activity was observed at 20 g/l wheat straw with S. lividans, while the optimum pH of xylanase formation was observed at pH 7. The effect of aeration, incubation period, enrichment of the utilized agricultural byproduct with yeast extract and glucose as the best nitrogen and carbon sources and the effect of heavy metal ions on the xylanase production by S lividans were studied. Maximum xylanases production was obtained from 75 ml fermented broth of S lividans. High level of xylanases production by S. lividans 15 U/ml was obtained after 4 and 5 days. On the addition of the best carbon and nitrogen source to the original substrate we found that, the level of enzyme formation was increased from 15.0 (Wheat straw without glucose or yeast) to 33.3 U/ml for S lividans. Ni++, Mn++ and Fe++ gave high stimulated xylanase enzyme formation by S lividans. Weak production of xylanases was detected when the medium contained Zn++ and Ld++ Co++ and Cu++. High enzyme precipitation was found by 50% cold acetone as partial enzyme purification. The optimum condition of xylanase activity produced by S. lividans was showed at pH 7.0 and optimum temperature of 50°C and stable for 35 min at the optimum condition 50°C and pH 7. Xylanase at a constant enzyme dosage, treated to bleach and deinke pulp of waste paper, can improve the properties of pulp more than the chemical treatment which cause environmental problems