以中性蛋白酶水解脱脂乳为培养基,研究脱脂乳水解度对植物乳杆菌KLDS1.0391发酵产抑菌物质的影响,并优化发酵pH和时间。采用毛细管电泳和SDS-PAGE技术分析不同水解度脱脂乳的肽分布,采用3.7L发酵罐,通过单因素试验确定发酵pH和时间。研究结果表明:15%水解度的脱脂乳中,酪蛋白被全部水解,乳清蛋白被部分水解,水解后的低分子量肽更易于被该菌利用;以15%水解度的脱脂乳为培养基,恒pH 5.0发酵24 h后,所产抑菌物质的抑菌活性最高,达538.53 IU/mL。

Skim milk which was hydrolyzed by neutral proteinase was used as medium for Lactobacillus plantarum KLDS1.0391.The effect of different degrees of hydrolysis of skim milk on antibacterial substances production by this strain was studied.Fermentation pH and time was optimized in 3.7 L fermentor by single factor experiment.The peptide distribution of skim milk of different degrees of hydrolysis was analyzed by capillary electrophoresis and SDS-PAGE.Results indicated that casein was completely hydrolyzed and whey was partly hydrolyzed in skim milk with DH of 15%.The peptide of low molecular weight after hydrolyzing was favored by Lactobacillus plantarum KLDS1.0391.Skim milk with DH of 15% was the suitable medium.The optimal constant pH and time for antibacterial substances production were 5.0 and 24 hours.The high level of antibacterial activity achieved 538.53 IU/mL.