一株发酵乳杆菌（Lactobacillus fermentium）对柠檬酸的发酵特性研究

Study on the Fermentation Characteristics of Citric Acid by a Lactobacillus fermentum

摘要:

本文讨论了一株能高效转化利用高酸性水果（如青梅）中柠檬酸的发酵乳杆菌菌株的发酵特性。结果表明，该菌株能在以柠檬酸为主要碳源和能源的基础培养液中进行发酵生长，在转化利用柠檬酸的过程中仅仅产生少量的乙酸和乳酸，因此能将培养液中可滴定酸含量降低50%以上。菌株对乙醇具有较高的耐受性，当培养液中乙醇浓度达到9% (V/V)以上时，菌株的生长和柠檬酸代谢也就受到明显的抑制；菌株对亚硫酸盐非常敏感，培养液中仅仅添加0.5 mM的亚硫酸钠后，菌株的生长和柠檬酸代谢将会被完全抑制。培养液中蔗糖的添加能促进菌株的生长和柠檬酸代谢，但在柠檬酸存在的情况下，该菌株对蔗糖的转化利用较弱，因此，发酵期间培养液中糖的总含量并没有出现明显的下降。

Abstract:

Fermentation characteristics by a Lactobacillus fermentum strain that can utilize citric acid in citrus fruits such as green plum were studied. Results showed that L. fermentum could grow in the basic culture medium with citric acid as the main source of carbon and energy. Citric acid metabolism yielded small amounts of acetic acid and lactic acid; hence, the total titratable acid content in the culture medium could be reduced by more than 50%. The strain has a high tolerance to ethanol, as ethanol concentration greater than nine percent (v/v) inhibits growth of the strain and citric acid metabolism. The strain is sensitive to sulfite; and the growth of the strain and citric acid metabolism are completely inhibited by 0.5 mM of sodium sulfite. Sucrose improved the growth of the strain and increased citric acid metabolism; however, no significant decrease in sucrose was observed during fermentation, indicating that the ability to utilize sucrose is low in the presence of citric acid.