产纤维素酶枯草芽孢杆菌的培养条件优化及发酵模型构建

Optimization of Growth Conditions of a Cellulase-Producing Bacillus Subtilis Strain and Its Growth Model Construction

为优化产纤维素酶枯草芽孢杆菌Z-4的培养条件,构建该菌生长、发酵产纤维素酶的模型,采用Plack-ett-Burman设计研究8种培养因素对Z-4菌体生长的影响,确定2个主要影响因素为MgSO4和葡萄糖。经最陡爬坡试验找到菌体生物量的最大响应区域。通过中心组合设计确定培养条件的最佳水平为:牛肉膏0.3%,Na-Cl0.5%,蛋白胨1%,葡萄糖0.627%,MgSO40.548%;温度30℃,时间24h,pH7.0。在此条件下,Z-4细胞干质量浓度的最大值为5.39g/L。经验证,较优化前提高23.48%。探索了Z-4发酵产酶过程中细胞生长和纤维素酶产物积累的规律,建立了相关数学模型,并较好地预测其动力学特征。

To optimize the cultural conditions of a cellulose-producing strain Bacillus subtilis Z-4 and construct the models of cell growth and cellulose production.Plackett-Burman methodology was used to optimize the cultural conditions for its growth,and two most important factors were selected.After steepest ascent path design was adopted to approach the optimal region of cell weight of Z-4,response surface method was used to determine the optimal levels of the main factors,and the optimized cultural conditions for Z-4 culture were as follows：beef extract 0.3%,NaCl 0.5%,pH 7.0,peptone 1%,glucose 0.627%,MgSO4 0.548%,temperature 30 ℃ and pH 7.0.Under those conditions,the dry cell mass reached 5.39 g/L,23.48% higher than those before the optimization.Meanwhile,changes of cell growth and cellulose production were also accessed.Mathematical models were then introduced to predict the kinetic mechanism.