Isolation and identification of halophilic microorganisms in soy sauce

Abstract

Microorganisms play an important role in the fermentation of soy sauce as they produce flavoring compounds which contribute to the desired taste and quality of soy sauce. The aim of this study was to isolate and identify halophilic microorganisms that are involved in the first stage (Koji) and second stage (Moromi) of soy sauce fermentation. In this study, soy sauce samples were collected from a local company located in Johor Bahru. The microorganisms were identified using Analytical Profile Identification (API) system and 16s ribosomal RNA (bacteria)/Internal Transcribed Spacer region (fungi and yeast) sequencing. In the koji fermentation, one fungus was isolated and identified as Aspergillus oryzae. During the moromi fermentation, one lactic acid bacteria and two yeasts were identified, including Tetragenococcus halophilus, Candida versatilis and Candida etchellsii. These halophilic microorganisms can be used as starter culture in moromi stage to shorten the fermentation period.