罗伊氏乳杆菌发酵液的抑菌特性与抑菌成分性质初探

Antimicrobial characteristics of Lactobacillus reuteri fermentation liquid and properties of its antimicrobial substances

研究了罗伊氏乳杆菌LYS-1发酵液的抑菌特性和初步探索了其抑菌成分的性质。发酵液的抑菌特性结果显示,LYS-1当活菌数≥1.00×109 cfu/mL时才会产生抑菌物质,发酵36 h后抑菌活性不随酸度的增大而增强。LYS-1发酵液具有良好的耐热能力,50~120℃处理30 min均对抑菌活性影响不大,但受pH的影响显著,pH≥5.50时发酵液的抑菌活性丧失,pH<5.50时才具有抑菌活性,且降低pH有利于增强抑菌效果,pH≤3.50时抑菌活性趋于稳定。抑菌成分性质的探索结果表明,发酵液经过氧化物酶处理后抑菌活性丧失了14.37%,蛋白酶K、胰蛋白酶和胃蛋白酶处理则对抑菌活性的影响不显著。发酵液经真空浓缩处理后,浓缩液和接收液均具有抑菌活性。发酵液与浓缩液分别经强酸水解后抑菌圈直径分别为0 mm和6.37 mm。LYS-1发酵液中不存在3-羟基丙醛。LYS-1发酵液的抑菌效果主要受p H影响,其抑菌物质应为多种组分,可能由小分子肽、过氧化氢和有机酸组成。

The antimicrobial characteristics of the fermentation liquid of Lactobacillus reuteri LYS-1 was studied and the properties of its antimicrobial substance was preliminarily explored. The results of antimicrobial characteristics of fermentation liquid showed that LYS-1 produced antimicrobial substances when the viable cell number was over 10~9 cfu/mL. The antimicrobial activity did not increase with the increase of acidity after 36 h of fermentation time. LYS-1 fermentation liquid was heat stable, and treatment at 50~120 ℃ for 30 min had little effect on antimicrobial activity. However, it was significantly affected by pH. When the pH≥5.50, the antimicrobial activity was lost. When the pH<5.50, fermentation liquid obtained antimicrobial activity, and reducing pH could enhance its effect. When the pH≤3.50, the antimicrobial activity tended to be stable. The results of exploration of properties of antimicrobial substances showed that the antimicrobial activity of fermentation liquid decreased by 14.37% after oxidase treatment, while the effect of protease K, trypsin and pepsin treatment was not significant. After vacuum concentration, both the concentrated liquid and the receiving liquid had antimicrobial activity. When the fermentation liquid and concentrated liquid was treated with strong acid, the diameter of antimicrobial zone was 0 mm and 6.37 mm, respectively. 3-hydroxypropionaldehyde did not exist in the LYS-1 fermentation liquid. Above all, the antimicrobial activity of LYS-1 fermentation liquid was mainly affected by pH, and its antimicrobial substances should be a variety of components, which may be composed of small molecular peptide, hydrogen peroxide and organic acids.