摘要
以Thermobi fidafusca WSH03-11为出发菌株,经硫酸二乙酯诱变,获得一株遗传稳定性好的高产角质酶的突变菌株(酶活由2.3U/mL提高为8.9U/mL)。确定了以乙酸钠为碳源,并在2.5L发酵罐中研究了不同pH值对突变株角质酶分批发酵的影响。根据不同pH值下发酵过程中细胞比生长速率及产物比生长速率的变化,确定了分阶段控制pH值的策略,即在发酵前20h控制pH值7.3、20h后控制pH值7.6,这种条件下角质酶活达到19.8U/mL,比采用单一pH值7.0、7.3、7.6、7.9下的最大值分别提高了125%,64%,37%,47%。
Thermobifida fusca WSH03-11 was mutagenized by using DES and a mutant was isolated after three runs of screening. The cutinase activity was improved from 2.3 U/mL to 8.9 U/mL. After sodium acetate was selected as fermentation carbon source, batch microbial cutinase fermentation by a mutant of Thermobifidafusca WSH03-11 at various pH values ranging from 7.0 to 7.9 was studied. Based on time courses of the specific cell growth rate and specific cutinase formation rate at different pH values, a two-stage pH value-shift strategy in which pH value was controlled at 7.3 in the first 20 h, and then switched to 7.6 after 20 h was developed. By applying this pH value-shift strategy in cutinase fermentation, the maximal cutinase activity reached 19.8 U/mL and was increased by 125%, 64%, 37% and 47%, compared to those with constant pH values at 7.0, 7.3, 7.6 and 7.9, respectively.
出处
《化工进展》
EI
CAS
CSCD
北大核心
2006年第5期533-537,共5页
Chemical Industry and Engineering Progress
基金
国家"863"计划(编号2003AA322050)
2005年新世纪优秀人才支持计划资助。
关键词
角质酶
诱变
pH值分段控制
细胞比生长速率
产物比生成速率
cutinase
mutagenesis
pH value-shift strategy
specific cell growth rate
specific cutinase formation rate
