一株近玫色锁掷酵母的分离鉴定及其产胞外乳糖酶性质的研究  

Isolation and identification of Sporidiobolus Pararoseus XWSP1 and its properties of extracellular lactase

作　　者：苑广伟 林梅 李镇标 孙玉红 王兆磊 王磊 YUAN Guangwei;LIN Mei;LI Zhenbiao;SUN Yuhong;WANG Zhaolei;WANG Lei(College of Materials and Energy, South China Agricultural University, Guangzhou 510642;Guangdong Weixin Biotechnology Company limited, Huizhou 516057;Shenzhen Weixin Biotechnology Company limited, Shenzhen 518116)

机构地区：[1]华南农业大学材料与能源学院,广州510642 [2]广东唯新生物科技有限公司,惠州516057 [3]深圳唯新生物科技有限公司,深圳518116

出　　处：《工业微生物》2020年第1期26-33,共8页Industrial Microbiology

基　　金：教育部蓝火计划(惠州)产学研联合创新资金(CXZJHZ201712)

摘　　要：从广州徐闻农垦丰收农场土壤样品中分离到一株产乳糖酶菌株,结合菌株形态特征和ITS基因序列同源性分析结果,表明该菌株为Saccharomycetes sp.的未定种,其系统分类学关系与近玫色锁掷酵母Sporidiobolus pararoseus strain AUMC 7791(JQ425362.1)最近,故命名为:近玫色锁掷酵母XWSP1(Sporidiobolus pararoseus XWSP1),该菌种保藏号为CCTCC NO:M2019119。该菌发酵液能水解邻硝基酚-β-D-半乳糖苷生成黄色的邻硝基酚,具有产乳糖酶性能。优化了该菌株发酵培养条件,结果表明:该菌株在蛋白胨15 g/L、酵母粉20 g/L、半乳糖20 g/L和初始pH 7.0的培养基中,以1×106 CFU/mL接种浓度、4%接种比例,28℃180 r/min恒温振荡培养54 h时,菌株分泌的胞外乳糖酶具有最高的活力。酶学性质初步研究结果表明,该胞外乳糖酶在pH 7.0的反应条件下酶活力最高,Ca^2+、Mn^2+、Mg^2+和Cu^2+对酶活有不同程度抑制作用,其中Cu^2+对酶活抑制作用最强。A lactase-producing strain XWSP1 was isolated from the soil of Xuwen Nongken Harvest Farm in Guangzhou.Based on its sequence and colony morphology,the strain was identified as undetermined species of Saccharomycetes sp.From the results of phygogenetic tree,XWSP1 and Sporidiobolus pararoseus strain AUMC 7791(JQ425362.1)had the closest evolutional relationship.Thus,it was named as Sporidiobolus pararoseus XWSP1,with the preservation number of CCTCC NO:M2019119.The fermentation broth of the strain could hydrolyze o-nitrophenol-β-D-galactoside to produce yellow o-nitrophenol,which indicated that the strain had the property of producing extracellular lactase.The fermentation medium and culture conditions of the strain were further optimized,and the results showed that the extracellular lactase secreted by the strain had the highest activity in the medium of peptone 15 g/L,yeast powder 20 g/L,galactose 20 g/L and initial pH 7.0.The highest extracellular lactase activity was obtained when the strain was cultured at 28℃,at inoculation concentration of 1×106 CFU/mL,inoculation ratio of 4%and 180 r/min for 54 h,The enzyme properties of lactase secreted by the strain were preliminarily studied.The results revealed that the extracellular lactase had the highest enzyme activity under the reaction condition of pH 7.0;and Ca^2+,Mn^2+,Mg^2+and Cu^2+had different inhibitory effects on enzyme activity,among them Cu^2+had the strongest inhibitory effect on enzyme activity.

关 键 词：近玫色锁掷酵母 ITS基因序列 胞外乳糖酶 发酵培养 酶活 

分 类 号：TS2[轻工技术与工程—食品科学与工程]