TR OPTIMAL CONDITIONS FOR β-MANNANASE PRODUCTION BY BACILLUS CIRCULANS NT 6.7

Optimum medium for mannanase production is very important and producing medium has been shown effective for mannanase production from Bacillus circulans NT 6.7 but expensive.  This work aim to find low cost medium and optimum condition for mannanase production from Bacillus circulans NT 6.7. 1.5% concentration of defatted copra meal as carbon source in shake flask resulted in highest growth and enzyme activities of 10.51±0.53 Log CFU/ml and 12.84±4.38 U/ml at 18 hours accordingly. Also, 2% defatted copra meal in fermenter produced highest growth of 7.94±0.41 Log CFU/ml and enzyme activities of 32.07±2.94 U/ml at 15 hours. Using taguchi design, optimal conditions for inoculum, agitation and aeration were 1%, 600 rpm and 0.75 vvm, respectively. Under this optimized condition, the mannanase experimental yield (29.57±4.81U/ml) closely matched the yield predicted by the statistical model (24.15U/ml) with R2 = 0.75. Using mineral salts medium, slightly increased in mannanase product was observed compare to previously used producing medium. Also, the cost of using mineral salts medium (cost per liter) is 27 time lower than the cost of producing medium. Suggesting that, mineral salt medium provides an economically feasible medium for producing mannanase from Bacillus circulans NT 6.7.