Bacillus globisporus N75 6-α-葡萄糖基转移酶在枯草芽孢杆菌中的重组表达  

Recombinant expression of Bacillus globisporus N756-α-glucosyltransferase in Bacillus subtilis

作　　者：刘玮琼 王蕾[1,2,3] 吴敬 陈晟[1,2,3] LIU Weiqiong;WANG Lei;WU Jing;CHEN Sheng(School of Biotechnology,Jiangnan University,Wuxi 214122,China;State Key Laboratory of Food Science and Resources,Jiangnan University,Wuxi 214122,China;Joint Laboratory of International Cooperation on Food Safety,Ministry of Education,Jiangnan University,Wuxi 214122,China)

机构地区：[1]江南大学生物工程学院,江苏无锡214122 [2]江南大学,食品科学与资源挖掘全国重点实验室,江苏无锡214122 [3]江南大学,教育部食品安全国际合作联合实验室,江苏无锡214122

出　　处：《食品与发酵工业》2024年第22期1-8,共8页Food and Fermentation Industries

基　　金：国家自然科学基金(31972032)。

摘　　要：6-α-葡萄糖基转移酶具有催化α-1,4-葡聚糖的外切水解和转糖基化功能,可通过转糖基活性产生非还原端连有α-1,6键的α-葡聚糖,可用于生产环交替糖及其分支衍生物和环异麦芽寡糖等新型功能糖。为了更好地将6-α-葡萄糖基转移酶应用于食品领域,该研究对来源于Bacillus globisporus N75的6-α-葡萄糖基转移酶在食品安全级菌株枯草芽孢杆菌中进行重组表达,并通过表达宿主的选择及优化发酵条件进一步提高重组蛋白产量。结果表明,宿主WHS9更有利于6-α-葡萄糖基转移酶的重组表达,在20℃的发酵条件下,胞内外可溶性总酶活力可达2.11 U/mL;在25℃添加20 mmol/L海藻糖发酵48 h后,总酶活力可达到2.21 U/mL;优化发酵时间后,发酵36 h总酶活力可达3.14 U/mL,是优化前WHS9表达酶活力的196倍。该研究首次实现了6-α-葡萄糖基转移酶在枯草芽孢杆菌中的重组表达。6-α-glucosyltransferase has catalytic activities of exo-hydrolysis towardsα-1,4-glucan and transglycosylation,and can produce theα-glucan which linksα-1,6 glycosidic bonds on the nonreducing end through transglycosylation activity.Therefore,it can be used to produce cyclic alternating sugars and their branched derivatives,as well as cycloisomaltooligosaccharide,which can be used as new functional sugar.To expand the application of 6-α-glucosyltransferase in the food industry,the 6-α-glucosyltransferase from Bacillus globisporus N75 was expressed heterologously in the food safety strain Bacillus subtilis,and the expression level of recombinant protein increased by selecting the host strain and optimizing fermentation condition.These results indicated that the host WHS9 was more beneficial for the recombinant expression of 6-α-glucosyltransferase and the total soluble enzyme activity could achieve 2.11 U/mL at 20℃,including intracellular and extracellular.After adding 20 mmol/L trehalose,the total enzyme activity could reach 2.21 U/mL at 25℃for 48 h.Then the fermentation period was optimized,and it was found that the highest enzyme activity could reach 3.14 U/mL at 36 h,which was 196 times higher than in WHS9 before optimization.This study firstly achieves recombinant expression of 6-α-glucosyltransferase in B.subtilis.

关 键 词：6-α-葡萄糖基转移酶 枯草芽孢杆菌 发酵优化 启动子 海藻糖 

分 类 号：TQ925[轻工技术与工程—发酵工程] Q78[生物学—分子生物学]