D-saccharic acid-1,4-lactone Producing Acetic Acid Bacteria in Kombucha Fermentation Process

Kombucha is a refreshing beverage with a slightly sour taste, obtained by the fermentation of probiotic microorganisms. The main compositions include acetic acid, lactic acid, gluconic acid, glucuronic acid as well as Dsaccharic acid-1,4-lactone (DSL). D-Saccharic acid-1,4-lactone (DSL) is a crucial substance involved in liver detoxification. DSL has ability to inhibits the activity of ?-glucuronidase, an enzyme related with cancers. The objective of this study was to isolate acetic acid bacteria which produced DSL from fruit, fermented fruit juices and kombucha. One hundred and fifty-three isolates of acetic acid bacteria were obtained from pineapple, 7 fermented fruit juices and 3 samples of kombucha. Sixty-eight isolates had ability to produced acid from green tea broth. They were selected for DSL production and compared with Acetobacter tropicalis P6. It was found that fourteen isolates, PM20, PM30, PM31, PM35, PM36, PM56, PM60, PM70, PM99, PM103, PM123, PM131, PM135, PM136 and A. tropicalis P6 gave the yield of DSL between 0.02 to 0.33 mg/ml.康普茶（Kombucha）是一款风味清爽、略带酸味的饮品，由益生菌微生物发酵制备而成。其主要成分包括乙酸、乳酸、葡萄糖酸、葡萄糖醛酸以及D-糖二酸-1,4-内酯（D-Saccharic acid-1,4-lactone，DSL）。D-糖二酸-1,4-内酯（DSL）是参与肝脏解毒过程的关键物质，同时可抑制与癌症相关的β-葡萄糖醛酸苷酶活性。本研究旨在从水果、发酵果汁及康普茶中分离出产DSL的醋酸菌（acetic acid bacteria）。研究人员从菠萝中获得153株醋酸菌分离株，另从7种发酵果汁与3份康普茶样本中获取醋酸菌分离株。其中68株能够在绿茶肉汤中产酸，因此被选用于DSL生产实验，并与热带醋酸菌P6（Acetobacter tropicalis P6）进行对照。结果显示，包括PM20、PM30、PM31、PM35、PM36、PM56、PM60、PM70、PM99、PM103、PM123、PM131、PM135、PM136在内的14株分离株，以及热带醋酸菌P6，其DSL产量介于0.02 mg/ml至0.33 mg/ml之间。