Microbacterium sp.XT11黄原胶内切酶在毕赤酵母中的异源表达、性质及应用  

Characterization and application of an endoxanthanase from Microbacterium sp.XT11 heterologous expressed in Pichia pastoris

作　　者：杨国帅 许颖 詹晓北[1] 蒋芸[1] 李志涛 高敏杰[1] YANG Guoshuai;XU Ying;ZHAN Xiaobei;JIANG Yun;LI Zhitao;GAO Minjie(School of Biotechnology,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

出　　处：《食品与发酵工业》2022年第6期8-14,共7页Food and Fermentation Industries

基　　金：国家重点研发计划“绿色生物制造”重点专项“生物反应器及智能生物制造”(2021YFC2101100)。

摘　　要：低分子质量黄原胶具有抗氧化、抑菌等特殊生物活性,在食品、农业等领域都有所应用,具有较高的市场价值。黄原胶内切酶的高效表达是酶法水解生产低分子质量黄原胶的关键因素。该研究首次在毕赤酵母GS115中表达来自Microbacterium sp.XT11的黄原胶内切酶,随后对其发酵条件进行了优化,并对重组黄原胶内切酶的酶学性质进行了分析。结果表明,以GAP为启动子的重组毕赤酵母的最佳发酵条件为30℃、pH 6.0、220 r/min、接种量5%,在7-L发酵罐中重组黄原胶内切酶酶活力达到1230 U/L。重组黄原胶内切酶在pH 5.5~7.5、20~45℃下比较稳定,最适作用条件为pH 6.0、40℃。重组黄原胶内切酶可直接作用于黄原胶主链得到分子质量为1400 Da左右的低分子质量黄原胶,为低分子质量黄原胶的工业化生产提供了一个可行的途径。Low-molecular-weight xanthan gum(LMWXG)has biological activities such as anti-oxidation,and anti-bacterium,it can be applied in food and agriculture fields.Endoxanthanase with high-level expression is a prerequisite for enzymatic preparation of LMWXG.The endoxanthanase gene from Microbacterium sp.XT11 was expressed in Pichia pastoris GS115 for the first time.The cultivation conditions of the recombinant Pichia pastoris were optimized.The enzymatic properties of the endoxanthanase were also studied.The optimal fermentation conditions for the recombinant P.pastoris with GAP promoter were 30℃,pH 6.0,220 r/min,and 5%inoculation.Under these conditions,the maximum activity of the recombinant endoxanthanase reached 1230 U/L in a 7-L bioreactor.The enzyme was relatively stable at pH 5.5-7.5 and 20-45℃.Its optimal pH and temperature were 6.0 and 40℃,respectively.It could directly hydrolyze the main chain of xanthan gum to form LMWXG(1400 Da).Therefore,this study may provide a feasible way for the industrial production of LMWXG.

关 键 词：黄原胶内切酶 毕赤酵母 发酵优化 酶学性质 低分子质量黄原胶 

分 类 号：TQ920.1[轻工技术与工程—发酵工程]