两阶段pH和搅拌控制策略提高哈茨木霉产β-1,3-葡聚糖内切酶
Enhancement of β-1,3-Endoglucanase Production by Trichoderma harzianum Using Two-Stage pH and Agitation Speed Control Strategy
DOI:10.3969/j.issn.1673-1689.2015.11.005
中文关键词: β-1,3葡聚糖内切酶 哈茨木霉 发酵策略 pH 搅拌转速
英文关键词: beta-1,3-endoglucanase,Trichoderma harzianum,two-stage strategy,pH,agitation speed
基金项目:
作者
单位
李珊
江南大学 生物工程学院,江苏 无锡214122
詹晓北
江苏瑞光生物科技有限公司,江苏 无锡 214125
郑志永
朱莉
李晶
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中文摘要:
为提高哈茨木霉(Trichoderma harzianum GIM 3.442)发酵生产β-1,3-葡聚糖内切酶的酶活Eendo及其内切酶酶活在总酶活中所占的比例Eendo/Etotal,在7 L发酵罐水平考察了不同pH和搅拌转速对菌体和产酶的影响。结果表明,单一pH或搅拌转速的优化不能使菌体生长和产物合成同时达到最优效果。通过分析不同pH和转速下发酵曲线和动力学参数,提出了两阶段pH和搅拌转速控制策略:在发酵前期(0~24 h)控制pH 7.0,搅拌转速100 r/min,发酵后期(24~168 h)控制pH 5.0,搅拌转速200 r/min。β-1,3-葡聚糖内切酶(Eendo)、酶合成生产强度(QE,endo)和Eendo/Etotal分别达到了407.8 U/mL、3.09 U/(mL?h)和0.71,比优化前分别提高了320.0%、398.4%和65.1%。
英文摘要:
Beta-1,3-endoglucanase has important applications in food,agriculture and biotechnology. To enhance the productivity of β-1,3-endoglucanase and its ratio in total β-1,3-glucanase activity by Trichoderma harzianum Rifai GIM 3.442,the effects of pH and agitation speeds were investigated in a 7 L fermentator. It was shown that the mono-control of pH or agitation speed could not satisfactorily offer higher biomass and β-1,3-endoglucanase production simultaneously. A two-stage pH and agitation speed control strategy was therefore employed,i.e.,pH and agitation speed were controlled at 7.0 and 100 r/min in the first stage of fermentation(0~24 h) and then switched to pH 5.0 and 200 r/min in the second stage(24~168 h). On account of this, β-1,3-endoglucanase activity and its productivity reached 407.8 U/mL and 3.09 U/(mL?h),320.0 % and 398.4 % higher than that of uncontrolled condition,respectively. The ratio of β-1,3-endoglucanase to total β-glucanases activity was 0.71,increasing 65.1 % than that of uncontrolled condition.
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