摘要
研究旨在应用响应面法对枯草芽孢杆菌(Bacillus subtilis)BY-3的发酵培养基进行优化,以提高纤维素酶产量、降低发酵成本。试验以羧甲基纤维素酶(CMCase)活性为响应值,通过单因素试验筛选出该菌株产酶的最适碳源和氮源,采用二水平的Pluckett-Burman筛选试验从8种潜在的培养基组分中筛选出能显著影响CMCase活性的因素,随后利用最陡爬坡试验逼近最大响应区域,最终通过中心组合试验(CCD)和响应面分析确定了显著因素的最优浓度。结果表明,B.subtilis BY-3产酶的最适碳源为玉米秸秆,最适氮源为豆粕;筛选出NaCl(X3)和玉米秸秆(X6)2个能显著影响CMCase活性的因素,得到最优的产酶发酵培养基:MgSO4·7H2O 0.3 g/l,K2HPO4·3H2O 1.5 g/l,NaCl5.772 g/l,酵母粉0.5 g/l,豆粕20 g/l,玉米秸秆28.499 g/l,CaCl2·2H2O 0.1 g/l,吐温80 0.1%(v/v)。在此培养基中发酵24 h,CMCase活性达到(5.305±0.073)U/ml,与模型预测值(5.263 U/ml)拟合良好。通过单因素试验和响应面优化,酶活较基础发酵培养基条件下[(1.683±0.049)U/ml]提高了近3.15倍。试验为作物秸秆的有效利用和纤维素酶制剂的开发提供帮助。
In order to enhance yield and reduce production cost in cellulase fermentation industry, re- sponse surface methodology （RSM） was employed to optimize a medium for production of eellulase hy thermophilie Bacillus subtilis BY-3. The single-factor design was initially used to screen the optimal carbon source and nitrogen source, respectively, from agro-industrial cellulosic residuals and by-prod- uets. Subsequently, a two factorial Plackett-Burman design was employed to identify the critical vari- ables for eellulase production, followed by the steepest ascent experiment for approaching the optimal response region rapidly and a five-level two-factor central composite design （CCD） for determining op- timum levels of critical variables.As a result, corn stover and soybean meal were screened as the opti- mal carbon source and nitrogen source, respectively. NaCI （X1） and eorn stover （X6） were identified as the critical variables for cellulase production and the optimized medium composition： MgSO4-7H20 0.3 g/l, K2HPO2-3H20 1.5 g/l, NaCI 5.772 g/l, yeast extract 0.5 g/l, soybean meal 20 g/l, corn stover 28.499 g/l, CaCI2.2H2O 0.1 g/l and Tween 80 0.1% （v/v）, for maximum cellulase produetion by B. sub- tiffs BY-3 was obtained by RSM. Under the optimal medium, an over all 3.15-fold inerease in cellu- lase yield with an average maximum carboxymethyl cellulase （CMCase） activity of （5.305＋0.073） U/ml was achieved in shake flasks after 24 h sub-merged fermentation, which showed good agree-ment with the predicted response （5.265 U/ml） by RSM. This study will provide a potential solution to utilize straws and develop cellulase preparation.
出处
《饲料工业》
北大核心
2014年第10期44-50,共7页
Feed Industry
基金
国家科技支撑计划项目[2011BAD28B05-3]
陕西科技创新项目[2011KTCL02-09]
关键词
枯草芽孢杆菌
纤维素酶
玉米秸秆
培养基优化
响应面法
Bacillus sublilis
cellulase
corn stover
medium optimization
response surface methodology
