SHIRKOT, C.K.GULERIA, SHIVANI2017-01-192017-01-19201047319http://krishikosh.egranth.ac.in/handle/1/97017ABSTRACT Industrial attention towards xylanase hyper production has consistently increased over the years, due to its potential use in several biotechnological applications such as use in clarification of juices, wine industries, poultry diets, animal feed, production of ethanol and application in biofuel. The present study is concerned with the improvement of wild strain of Bacillus macerans for enhanced xylanase production using physical mutagen (ultraviolets rays) and chemical mutagens (ethidium bromide (0.1-2.0 mg/ml) and ethyl methanesulfonate (5-70 mg/ml)). Seventy five isolates were selected on the basis of clear zones of xylan hydrolysis and change in morphology. Only one mutant (E5) with hyper xylanase production was obtained after treating wild strain with EMS (70 mg/ml) for 50 miniutes which gave 14.87 U/ml enzyme activity. Two mutants M5 (UV mutant) and M11 2 (UV & Et Br mutant) with decreased xylanase activity were also selected for further studies. Maximum enzyme production (14.87 U/ml) for mutant E5 was observed, when fermentation medium, supplemented with 0.5% yeast extract and pH 8.0 was incubated at 35°C for 72 h with 1.0% inoculun size and xylan as carbon source. Mutant E5 resulted in 22.99 per cent increase over wild strain in xylanase activity in liquid medium and 11.96 per cent increase was observed in solid state fermentation with apple pomace as substrate under optimized conditions. The results obtained in the present study, indicate towards the effectiveness of alkalophilic and hyper xylanae producing mutant strain of Bacillus macerans (E5) and its possible applicability in paper and pulp industry.enThesis