泡椒汁中耐受辣椒素乳酸菌的筛选及其耐受性研究

Screening and tolerance of capsaicin-tolerant lactic acid bacteria in pickled pepper juice

为强化发酵生产泡椒提供耐受辣椒素的乳酸菌,在四川农家自制泡椒老卤水中筛选并鉴定出一株耐受辣椒素植物乳杆菌(Lactobacillus plantarum)Y-6,在0.5 g/L辣椒素下的相对生长率为(70.16±0.03)%;菌液电导率、核酸蛋白泄漏、菌体细胞超微结构测定结果表明,辣椒素通过破坏乳酸菌的壁膜结构延滞其生长;菌株Y-6在IC_(50)(0.571 g/L)辣椒素处理下仍能保持细胞形态相对完整,受辣椒素的抑制作用低于商用乳酸菌6239;RT-qPCR结果表明,Y-6通过调节usp等应激蛋白基因表达应对辣椒素引起的膜损伤;调节相容性溶质调控系统基因以及ABC转运蛋白渗透酶基因的表达维持菌体渗透压的平衡;通过提高糖酵解等与生长代谢相关基因表达,维持其在辣椒素环境中的生长代谢。菌株Y-6对辣椒素有较高的耐受性,可为发酵辣椒的工业化生产和菌株改良育种工作的开展提供理论依据。

In order to provide capsaicin-tolerant lactic acid bacteria for the production of pickled pepper by enhanced fermentation,a capsaicin-tolerant Lactobacillus plantarum Y-6 was screened and identified from the old brine of homemade pickled pepper in Sichuan.The relative growth rate under 0.5 g/L capsaicin was(70.16±0.03)%.The results of bacterial conductivity,nucleic acid and protein leakage,and bacterial cell ultrastructure showed that capsaicin delayed the growth of lactic acid bacteria by destroying the wall membrane structure of lactic acid bacteria.Strain Y-6 could maintain relatively intact cell morphology under IC 50(0.571 g/L)capsaicin treatment,and the inhibitory effect of capsaicin was lower than that of commercial lactic acid bacteria 6239.RT-qPCR results showed that Y-6 responded to capsaicin-induced membrane damage by regulating the expression of stress protein genes such as usp;regulating the expression of compatible solute regulatory system genes and ABC transporter permease genes to maintain the balance of bacterial osmotic pressure;maintaining its growth and metabolism in the capsaicin environment by increasing the expression of genes related to growth and metabolism such as glycolysis.Y-6 strain has high tolerance to capsaicin,which can provide a theoretical basis for the industrial production of fermented pepper and the improvement of strain breeding.