甾醇酯酶菌株Chryseobacterium sp.的筛选及酶学性质研究  

Screening of Sterol Esterase-producing Strain Chryseobacterium sp. and Its Emzymatic Properties

作　　者：曾诚[1] 范远鑫[1] 丁少军[1] 

机构地区：[1]南京林业大学化学工程学院,江苏南京210037

出　　处：《林产化学与工业》2013年第3期43-49,共7页Chemistry and Industry of Forest Products

基　　金：江苏高校优势学科建设工程资助项目(PAPD)

摘　　要：设计了一种以植物甾醇酯为底物,罗丹明B为荧光指示剂的平板筛选方法,从土壤中筛选得到24株具有甾醇酯酶活性的菌株,其中编号为jxpLT的菌株具有最高产酶活性,经16S rDNA鉴定表明菌株jxpLT属于金黄杆菌属,命名为Chryseobacterium sp.jxpLT。在优化的产酶条件下,菌株jxpLT培养18 h产酶活性最高可达到0.194 IU/mL。初步纯化了Chryseobacteri-um sp.jxpLT的甾醇酯酶并研究其部分酶学性质,该酶的酶促反应最适温度为40℃,最适pH值为7.5,其在45℃以下,pH值5.0～9.0具有较好的稳定性。该酶对不同碳链长度的脂肪酸胆固醇酯和对硝基苯酚酯具有广泛的底物特异性,显示该甾醇酯酶具有解决机械制浆造纸工艺中树脂障碍问题的潜力。Twenty four strains for production of sterol esterase were screened from soil by using a plate assay in a medium contai- ning sterol ester as a substrate and rhodamine B as the fluorescent. Among these strains, the jxpLT, which was found to produce the highest level of sterol esterase, belongs to genus Chryseobacterium based on 16S rDNA sequencing analysis and then was des- ignated as Chryseobacterium sp. jxpLT. The maximum enzyme activity of this strain was 0. 194 IU/mL after 18 h incubation under the optimized culture conditions. The sterol esterase was preliminary purified by ion exchange chromatography on DEAE Sepha- rose Fast Flow column and its enzymatic properties were investigated. This enzyme showed an optimum activity at pH 7.5 and 40 ℃. The enzyme had a good stability below 45℃ and the pH in 5.0 - 9.0. Chryseobacterium sp. jxpLT sterol esterase can hydrolyze cholesterol esters and PNP esters of different fatty acids. It may have the potential to solve the pitch problems caused by lipophilic extractives during wood mechanical pulping process.

关 键 词：甾醇酯酶 金黄杆菌属 酶学性质 

分 类 号：TQ35[化学工程]