Diversity of a Lactic Acid Bacterial Community during Fermentation of Gajami-Sikhae, a Traditional Korean Fermented Fish, as Determined by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry.

Gajami-sikhae is a traditional Korean fermented fish food made by naturally fermenting flatfish ( Glyptocephalus stelleri ) with other ingredients. This study was the first to investigate the diversity and dynamics of lactic acid bacteria in gajami-sikhae fermented at different temperatures using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A total of 4824 isolates were isolated from the fermented gajami-sikhae. These findings indicated that Latilactobacillus , Lactiplantibacillus , Levilactobacillus , Weissella , and Leuconostoc were the dominant genera during fermentation, while the dominant species were Latilactobacillus   sakei , Lactiplantibacillus   plantarum , Levilactobacillus   brevis , Weissella   koreensis , and Leuconostoc   mesenteroides . At all temperatures, L. sakei was dominant at the early stage of gajami-sikhae fermentation, and it maintained dominance until the later stage of fermentation at low temperatures (5 °C and 10 °C). However, L . plantarum and L . brevis replaced it at higher temperatures (15 °C and 20 °C). The relative abundance of L. plantarum and L. brevis reached 100% at the later fermentation stage at 20 °C. These results suggest that the optimal fermentation temperatures for gajami-sikhae are low rather than high temperatures. This study could allow for the selection of an adjunct culture to control gajami-sikhae fermentation.