Isolation and characterization of lactic acid bacteria from Yan-dong-gua (fermented wax gourd), a traditional fermented food in Taiwan

Yan-dong-gua (fermented wax gourd; a traditional fermented food in Taiwan) samples were collected at five time intervals from a fixed fermenting bucket. Eighty-five cultures of lactic acid bacteria (LAB) were isolated from Yan-dong-gua samples, and the isolates were divided into classes by phenotype and then groups by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. Phenotypic and biochemical characteristics identified two bacterial groups (A and B) and showed that the majority of the isolates were heterofermentative LAB. Weissella cibaria was the major LAB found during the initial fermentation of yan-dong-gua. However, it was mostly replaced by W. paramesenteroides after 5 days of fermentation. All isolated LAB were able to grow in MRS broth containing 6% NaCl. Furthermore, the antibacterial activities of the isolates were determined, and five of the isolates showed inhibitory activities against the indicator strain Lactobacillus sakei subsp. sakei JCM 1157T. These results suggest that W. cibaria and W. paramesenteroides are the main LAB present during the fermentation of yan-dong-gua. This is the first report describing the distribution and varieties of LAB that exist in the yan-dong-gua fermentation process.