Characterisation and application of Halomonas shantousis SWA25, a halotolerant bacterium with multiple biogenic amine degradation activity

Biogenic amines are identified as toxicological substances in foods and may have detrimental effects on consumers’ health. In recent years, the application of microorganisms that can degrade biogenic amines has become an emerging method for their reduction. The degradation characteristics and application potential of a salt-tolerant bacterium Halomonas shantousis SWA25 were investigated in this study. H. shantousis SWA25 exhibited degradation activity against eight biogenic amines at 10–40°C (optimum, 30–40°C) and pH 3.0–9.0 (optimum, 6.0–7.0) in the presence of 0–20% (w/v) NaCl (optimum, 0%). Specifically, H. shantousis SWA25 degraded all tryptamine (TRY) and tyramine (TYR) in 6 h, all phenethylamine (PHE) in 9 h, 66.7% of histamine (HIM), 52.4% of cadaverine (CAD), 48.0% of spermidine (SPD), 42.9% of putrescine (PUT) and 42.0% of spermine (SPM) in 20 h at 30°C and pH 7.0 with shaking at 120 r min−1. The enzymes from H. shantousis SWA25 responsible for degradation of biogenic amines were mainly amine oxidases located on the cell membrane. Further studies showed that H. shantousis SWA25 effectively degraded TRY, PHE, PUT, CAD, HIM and TYR in commercial fish sauce and soy sauce samples. Nevertheless, significant SPD and SPM degradation were not observed due to low initial concentrations. Therefore, H. shantousis SWA25 can be applied as a potential biogenic amines degradation bacterium in foods.