植物乳杆菌ZS2058在磷酸盐缓冲液体系中生物转化共轭亚油酸

Bioconversion of conjugated linoleic acid by resting cells of Lactobacillus plantarum ZS2058 in potassium phosphate buffer system

摘要:

植物乳杆菌ZS2058是从泡菜中筛选到一株具有转化共轭亚油酸能力的乳酸菌。该菌株在MRS培养基中经0.5mg/mL的亚油酸诱导培养后,所获得的菌体细胞具有较强的转化能力。文中就植物乳杆菌ZS2058水洗细胞在磷酸盐缓冲液体系中生物转化共轭亚油酸进行了深入研究。在非厌氧条件下,植物乳杆菌ZS2058在亚油酸浓度为1mg/mL,湿细胞质量浓度约为150mg/mL,120r/min、37℃的条件下反应24h后,能将亚油酸转化为共轭亚油酸和羟基脂肪酸,其中c9,t11-CLA占所产生的CLA总量的96.4%,产量可高达312.4μg/mL,说明该菌株有很强的专一性。随着反应进一步进行,反应至36h时,c9,t11-CLA含量逐渐减少,伴随着大量羟基脂肪酸的产生;并且,以CLA(c9,t11-CLA和t10,c12-CLA的混合样品)为底物进行反应时,c9,t11-CLA被转化为羟基脂肪酸。由此可知,c9,t11-CLA可能是该菌株生物转化LA过程中的一个中间产物。

Abstract:

Lactobacillus plantarum ZS2058, which was screened from the Chinese traditional fermented vegetable，has the capacity to convert the linoleic acid(LA) into conjugated linoleic acid (CLA). Some specific isomers of CLA with potentially beneficial physiological and anticarcinogenic effects, were efficiently produced from free linoleic acid by washed cells of Lactobacillus plantarum ZS2058 under aerobic conditions. The produced CLA isomers are identified as the mixture of cis-9,trans-11-octadecadienoic acid (CLA1) trans-10, cis-12- octadecadienoic acid (CLA2),96.4% of which is CLA1. The washed cells of Lactobacillus plantarum ZS2058 producing high levels of c9,t11-CLA were obtained by cultivated in MRS media containing 0.5mg/mL linoleic acid, indicating that the enzyme system for CLA production is induced by linoleic acid. After a 24-hour bioconversion at 37℃ with shaking (120 r/min), 312.4μg/mL c9,t11-CLA is produced. And after a 36-hour bioconversion, the content of c9,t11-CLA decreases while hydroxy-octadecaenoic acid increases. In addition, the c9,t11-CLA isomer can be transformed to hydroxy- octadecaenoic acid when the mixed CLA (c9,t11-CLA and t10,c12-CLA ) were used as the substrate ，which suggests that c9,t11-CLA is one of the intermediates of the bioconversion products from free LA by washed cells of Lactobacillus plantarum ZS2058.