Isolation and characterization of halophilic lactic acid bacteria acting as a starter culture for sauce fermentation of the red alga Nori ( Porphyra yezoensis)

AimsA screening test was conducted for environmental samples to isolate halophilic lactic acid bacteria (HLAB) that can act as a starter in a Nori (Porphyra yezoensis)-sauce culture. Method and ResultsAfter 9months of incubation of enrichment cultures added with 25 kinds of environmental samples, growth of HLAB-like microorganisms was observed in six cultures salted at a 15% w/w level, including culture samples originally from mesopelagic water taken from 321m-depth and from mountain snow taken at 2450m-height. Ten strains were isolated and characterized as Tetragenococcus halophilus based on sequence analysis of the 16S rRNA gene. The isolates were inoculated into a newly prepared Nori-sauce culture and were confirmed to be able to act as a starter culture while three reference strains of T.halophilus obtained from a culture collection could not grow in the same culture. ConclusionsHalophilic lactic acid bacteria strains that can make growth in a highly salted Nori-sauce culture were isolated from environmental samples for the first time. All the isolates were identified as T.halophilus. Significance and Impact of the StudyThe isolated strains are expected to be utilized as a starter culture for manufacturing fermented seaweed-sauce, which will be the first fermented food products obtained from algae.