Abstract Biphenyl-degrading bacteria were isolated from contaminated soil and identified as Comamonas species. Among these strains, C. thiooxydans N1 was the most suitable for biphenyl degradation. When 1200 µg/mL of biphenyl was used, it was completely degraded within 24 h. A simple, rapid, and precise, high-performance liquid chromatography (HPLC) method for quantifying biphenyls and their metabolites in the culture medium was optimised and validated. The proposed method was performed using reverse-phase HPLC equipped with a Luna C18 column. The mobile phase was water and acetonitrile (30/70, v/v) under isocratic conditions, and biphenyls and their metabolites were quantified on a SHIMADZU HPLC system with a diode-array detection detector at 254 nm. Peak identity was confirmed by ultraviolet spectroscopy and gas chromatography-mass spectrometry. Validation was performed according to European Union requirements (2002/657/EC) for linearity, accuracy, repeatability, reproducibility, limit of detection, limit of quantification, and detection capability. Linearity was observed in the concentration range of 0.04-20 µg/mL with a high coefficient of determination (R2 ≥ 0.999). The validated method was applied to determine the content of biphenyl and its metabolites in the culture medium.

Abstract A high concentration of histamine, one of the biogenic amines (BAs) usually found in fermented foods, can cause undesirable physiological side effects in sensitive humans. The objective of this study is to isolate indigenous Acetobacter strains from naturally fermented Bokbunja vinegar in Korea with reduced histamine production during starter fermentation. Further, we examined its physiological and biochemical properties, including BA synthesis. The obtained strain MBA-77, identified as Acetobacter aceti by 16S rDNA homology and biochemical analysis and named A. aceti MBA-77. A. aceti MBA-77 showed optimal acidity % production at pH 5; the optimal temperature was 25 °C. When we prepared and examined the BAs synthesis spectrum during the fermentation process, Bokbunja wine fermented with Saccharomyces cerevisiae showed that the histamine concentration increased from 2.72 of Bokbunja extract to 5.29 mg/L and cadaverine and dopamine was decreased to 2.6 and 10.12 mg/L, respectively. Bokbunja vinegar prepared by A. aceti MBA-77 as the starter, the histamine concentration of the vinegar preparation step was decreased up to 3.66 mg/L from 5.29 mg/L in the wine preparation step. To our knowledge, this is the first report to demonstrate acetic acid bacteria isolated from Bokbunja seed vinegar with low spectrum BA and would be useful for wellbeing vinegar preparation.