ENHANCED XYLANASE PRODUCTION BY MUTANT STRAINS OF Bacillus macerans IN SOLID STATE FERMENTATION OF APPLE POMACE
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Date
2010
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Abstract
ABSTRACT
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.