Rajagopalan Gobinath, Krishnan Chandraraj
Department of Biotechnology, Indian Institute of Technology Madras, Chennai 600 036, India.
Bioresour Technol. 2008 May;99(8):3044-50. doi: 10.1016/j.biortech.2007.06.001. Epub 2007 Jul 17.
A catabolite derepressed Bacillus subtilis strain KCC103 was used to produce alpha-amylase in medium containing sugarcane bagasse hydrolysate (SBH). Addition of SBH (1% reducing sugar (w/v)) to the nutrient medium supported maximum alpha-amylase production of 67.4 Um l(-1). HPLC analysis of SBH showed the presence of glucose, xylose and arabinose in the ratio of 0.9:1.0:0.16 (w/w/w). In SBH-medium glucose and xylose were consumed completely while arabinose remained unutilized. Uptake rate of glucose was 2-folds higher than xylose but rate of alpha-amylase production with xylose was 1.5-folds higher than glucose. Arabinose had no effect on growth and alpha-amylase synthesis. Further, alpha-amylase production in SBH-medium was enhanced to 144.5 Um l(-1) (2.2-fold) by response surface methodology where the levels of SBH, and other media components were varied. The modified medium consisted of (in gl(-1)) SBH: 24; peptone: 17.43; yeast extract: 1.32 and beef extract: 1.82. High level of SBH showed no significant inhibition of alpha-amylase synthesis. The derepressed strain KCC103 is useful to produce alpha-amylase economically in short time (30-36 h).
使用一种分解代谢物阻遏解除的枯草芽孢杆菌菌株KCC103在含有甘蔗渣水解物（SBH）的培养基中生产α-淀粉酶。向营养培养基中添加SBH（1%还原糖（w/v））可支持最大α-淀粉酶产量达到67.4 U/ml（-1）。对SBH的HPLC分析表明，葡萄糖、木糖和阿拉伯糖的存在比例为0.9:1.0:0.16（w/w/w）。在SBH培养基中，葡萄糖和木糖被完全消耗，而阿拉伯糖未被利用。葡萄糖的摄取速率比木糖高2倍，但木糖的α-淀粉酶产生速率比葡萄糖高1.5倍。阿拉伯糖对生长和α-淀粉酶合成没有影响。此外，通过响应面法，在改变SBH和其他培养基成分水平的情况下，SBH培养基中的α-淀粉酶产量提高到了144.5 U/ml（-1）（2.2倍）。改良后的培养基组成（每升）为：SBH：24；蛋白胨：17.43；酵母提取物：1.32；牛肉提取物：1.82。高浓度的SBH对α-淀粉酶合成没有显著抑制作用。解除阻遏的菌株KCC103有助于在短时间（30 - 36小时）内经济地生产α-淀粉酶。
