摘要
β-1,4-内切葡聚糖酶在洗涤行业有着广泛的应用价值,其中具有较好的低温和碱性耐受能力是其实现工业应用的重要前提。该论文通过基因挖掘获得一株具有低温耐受能力的Deinococcus cellulosilyticus来源新型β-1,4-内切葡聚糖酶基因EgDC,并将其在大肠杆菌中实现了可溶性表达,其中大部分存在于周质空间,少部分分泌至胞外。对EgDC酶的酶学性质进行了表征,发现该酶的最适温度和最适pH值分别为40℃和pH 6.5,其在20℃能保持70%以上活力,且在pH 8.0和pH 9.0的半衰期分别达到83.43 min和53.79 min。EgDC酶具有较好的催化性质,其比酶活力k_(cat)/K_(m)值分别为(26.38±1.43)U/mg和(520.03±17.07)s^(-1)/mg,且对于金属离子以及表面活性剂均具有较强耐受能力。由此可见,新型β-1,4-内切葡聚糖酶EgDC具有较好的催化能力,且在低温、碱性以及存在表面活性剂环境下较为稳定,因此具有潜在的工业应用价值。
There is a wide range of applications forβ-1,4-endoglucanase in the detergent industry,which with good low temperature and alkaline tolerance is an important prerequisite for its industrial application.In this thesis,a novelβ-1,4-endoglucanase gene EgDC from Deinococcus cellulosilyticus with low-temperature tolerance was obtained by gene mining.It was expressed in Escherichia coli,with most of it existed in the periplasmic space and a small portion secreted to the extracellular space.The enzymatic properties of EgDC enzyme were characterized,and it was found that the optimum temperature and pH of the enzyme were 40°C and pH6.5,respectively.It could maintain more than 70%of its activity at 20°C,while its half-life reached 83.43 min and 53.79 min at pH8.0 and pH9.0.Theβ-1,4-endoglucanase EgDC had good catalytic properties with specific enzyme activity and k_(cat)/K_(m) values reaching(26.38±1.43)U/mg and(520.03±17.07)s^(-1)/mg,respectively,which is also highly tolerant to metal ions and surfactants.Thus,the newβ-1,4-endoglucanase EgDC has good catalytic ability and is stable at low temperature,alkaline environment and in the presence of surfactant.Therefore,it has potential industrial applications.
作者
圣弟青
钮成拓
闫亚楠
郑飞云
刘春凤
王金晶
李崎
SHENG Diqing;NIU Chengtuo;YAN Yanan;ZHENG Feiyun;LIU Chunfeng;WANG Jinjing;LI Qi(Key Laboratory of Industrial Biotechnology,Ministry of Education,Jiangnan University,Wuxi 214122,China)
出处
《食品与发酵工业》
CAS
CSCD
北大核心
2024年第4期17-24,共8页
Food and Fermentation Industries
基金
国家重点研发计划子课题(2021YFC2100404)。
关键词
基因挖掘
β-1
4-内切葡聚糖酶
异源表达
酶学性质
低温
耐碱性
gene mining
β-1,4-endoglucanase
heterologous expression
enzymatic properties
low temperature
alkaline tolerance
