甜菜汁中耐高糖乳酸菌的筛选及其发酵生产胞外多糖抗氧化活性的研究

Screening of High Sucrose-tolerant Lactic Acid Bacteria and Its Fermentation of Exopolysaccharides with Antioxidant Capacity in Beet JuiceZHANG Han1, REN Gaoyu2,GAN Hao2,CHEN Haijun1, LI Qiuxiao3, ZHAO Shuna3*, SHEN Guanghui2*

中文关键词:  甜菜糖蜜,植物乳植杆菌,胞外多糖,发酵条件优化,抗氧化活性

英文关键词:Beet  molasses, Lactiplantibacillus  plantarum, Exopolysaccharides, Fermentation  optimization, Antioxidant  activity

中文摘要:

      【目的】挖掘甜菜浸出汁中耐高糖且高产胞外多糖乳酸菌,评估其生物转化甜菜糖蜜开发功能胞外多糖的潜力。【方法】以胞外多糖产量和耐高糖生长能力对分离自甜菜浸出汁的乳酸菌菌株进行双重筛选,通过形态特征结合16S rRNA测序对1株较强应用潜力的菌株COFL4进行鉴定,采用单因素结合Box-Behnken响应面法对COFL4利用甜菜糖蜜合成胞外多糖的摇瓶发酵条件进行优化,并对获得的胞外多糖体外抗氧化活性进行评价。【结果】菌株COFL4被鉴定为植物乳植杆菌(Lactiplantibacillus plantarum),在蔗糖质量浓度450 g/L培养基中生长良好,其利用甜菜糖蜜发酵胞外多糖的最佳条件为:甜菜糖蜜添加量30%,发酵温度31℃、摇床转速32 r/min、装液量180 mL/250 mL、初始pH值7.0、发酵时间36 h,此条件下胞外多糖产量为12.73 g/L,较优化前提高了79%。体外抗氧化活性表明,COFL4发酵获得的胞外多糖具有良好的抗氧化活性。【结论】植物乳植杆菌COFL4具有生产抗氧化活性胞外多糖的潜在前景。

英文摘要:

      [Objective] The objective of this study is to explore the high glucose-tolerant and high exopolysaccharides (EPS)-producing lactic acid bacteria (LAB) isolated from sugar beet juice and to assess their potential for bioconversion of sugar beet molasses to functional EPS. [Methods] LAB strains isolated from beet juice were subjected to a double screening process to assess their potential for EPS production and high sucrose tolerance. Strain COFL4, was identified as a promising candidate for further investigation based on its morphological characteristics and 16S rRNA analysis. The shaking flask fermentation conditions for the synthesis of EPS from beet molasses by COFL4 were optimized using a one-way combination of Box-Behnken response surface methodology. The antioxidant activity in vitro of EPS from COFL4 were evaluated.? [Results] The strain COFL4 was identified as Lactiplantibacillus plantarum, which grew well in sucrose mass concentration of 450 g/L medium, and its optimal conditions for EPS production from sugar beet molasses were: 30% addition of sugar beet molasses, fermentation temperature of 31°C, shaker speed of 32 r/min, loading volume of 180 mL/250 mL, initial pH of 7.0, and fermentation time of 36 h. The EPS yield under these conditions was 12.73 g/L, which was 79% higher than that before optimization. The in vitro antioxidant activity showed that EPS from COFL4 had good antioxidant activity. [Conclusion] L. plantarum COFL4 is a promising strain for the conversion of sugar beet molasses to EPS with good antioxidant activity.