Page 93 - 精细化工2019年第9期

第 36 卷第 9 期 精 细 化 工 Vol.36, No.9
201 9 年 9 月 FINE CHEMICALS Sept. 2019

生物工程
有机介质中包衣菌体催化合成 c9,t11-共轭亚油酸

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张凯强，曾艳红，李慧美，李海星，郭雨韵，刘晓华
（南昌大学 中德联合研究院 食品科学国家重点实验室，江西 南昌 330047）

摘要：以 3 种脂肪醇（正辛醇、月桂醇和肉豆蔻醇）为原料，合成得到 3 种谷氨酸二烷基酯核糖醇（2C 8 GE、
2C 12 GE 和 2C 14 GE），比较了不同谷氨酸二烷基酯核糖醇及其浓度和所用溶剂种类，以及缓冲液 pH、包衣时间、
温度和干燥方式对包衣 Lactobacillus helveticus L7 菌体酶活的影响。确定了制备包衣菌体的条件为：表面活性剂
为谷氨酸双十二烷基酯核糖醇（2C 12 GE），将其配制成质量分数为 1.0%的丙酮溶液；菌体用 pH 5.8 的磷酸盐缓
冲液重悬；在 4 ℃下处理 4 h 经冷冻干燥而成包衣菌体。亚油酸经包衣菌体催化 18 h 后，其转化率为 95.3%，
c9,t11-共轭亚油酸的产量为 1906 mg/L。包衣菌体在有机溶剂中重复使用 5 次仍然具有较高的催化活性。在以亚
油酸为底物时，包衣菌体中亚油酸异构酶的米氏常数（K m ）为 35.7 mmol/L，最大反应速度（V max ）为 5.6 mmol/h。
经包衣处理后，菌体中亚油酸异构酶和底物的亲和力有所降低。
关键词：c9,t11-共轭亚油酸；生物合成；包衣菌体；有机介质；生物工程
中图分类号：TQ426.97 文献标识码：A 文章编号：1003-5214 (2019) 09-1821-06

Surfactant-coated Bacteria as a Catalyst for Biosynthesis of
c9,t11-Conjugated Linoleic Acid in Organic Solvent

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ZHANG Kai-qiang, ZENG Yan-hong, LI Hui-mei, LI Hai-xing, GUO Yu-yun, LIU Xiao-hua
（Sino-German Joint Research Institute, State Key Laboratory of Food Science and Technology, Nanchang University,
Nanchang 330047, Jiangxi, China）

Abstract: Three glutamic acid dialkyl ester ribitols (abbreviated as 2C 8GE, 2C 12GE and 2C 14GE) as
nonionic surfactants were synthesized from three fatty alcohols (n-octyl alcohol, lauryl alcohol and myristyl
alcohol). The effects of types and concentrations of glutamic acid dialkyl ester ribitols, solvent, buffer pH,
coating time, temperature and drying method on the activity of enzyme in coated Lactobacillus helveticus
L7 were studied. The optimized coating conditions were obtained as follows: didodecanyl glutamate ribitol
(2C 12GE) was the suitable surfactant, which was prepared into acetone solution with a mass fraction of
1.0%, becteria was resuspended in phosphate buffer of pH 5.8, incubated at 4 ℃ for 4 h, and lyophilized.
Linoleic acid was catalyzed by surfactant-coated bacteria for 18 h, and its conversion rate was 95.3%, and
the yield of c9,t11-conjugated linoleic acid was 1906 mg/L. The surfactant-coated bacteria could be reused
for five times without loss of catalytic activity in organic solvent. The Michaelis constant (K m) of linoleic
acid isomerase for lionleic acid as substrate was 35.7 mmol/L and the maximum reaction velocity (V max) of
was 5.6 mmol/h. The affinity of linoleic acid isomerase and linoleic acid decreased as the bacteria was
coated with surfactant.
Key words: c9,t11-conjugated linoleic acid; biosynthesis; surfactant-coated bacteria; organic solvent;
biological engineering

共轭亚油酸（conjugated linoleic acid, CLA）是 动物牛和羊的乳脂和体脂中，主要由 c9,t11-CLA 等
[1]
亚油酸的共轭异构体，其在自然界主要存在于反刍 异构体组成 ，但其含量很低，通常每克脂肪含量

收稿日期：2019-01-12; 定用日期：2019-03-28; DOI: 10.13550/j.jxhg.20190042
基金项目：江西省重点研发计划项目（20171BBE50033）
作者简介： 张凯强（1993—），男，硕士生，E-mail：790400754@qq.com。联系人：刘晓华（1973—），男，研究员，E-mail：liuxiaohua@
ncu.edu.cn。