전통 발효 청국장으로부터 biogenic amine 저생성 미생물의 선발

Abstract

본 연구에서는 청국장 및 볏짚에서 분리한 미생물중 decarboxylase 배지에서 탈탄산효소 활성이 낮은 균주로 <TEX>$B.$</TEX> <TEX>$subtilis$</TEX> HH12, <TEX>$B.$</TEX> <TEX>$subtilis$</TEX> HR254, <TEX>$P.$</TEX> <TEX>$barcinonensis$</TEX> KR97을 선발하였다. 이들 선발 미생물들의 histidine decarboxylase(<TEX>$hdc$</TEX>) gene 과 tyrosine decarboxylase(<TEX>$tdc$</TEX>) gene을 조사한 결과, <TEX>$hdc$</TEX> gene은 HH12, HR254, KR97 균주에서는 검출되지 않았으나, <TEX>$tdc$</TEX> gene은 HH12, HR254, KR110 균주에서 검출되었다. 또한 HPLC를 통해 선발 균주들의 배양상등액 중 amines 생성량을 분석한 결과, HH12, HR254, KR110 균주는 histamine이 검출되지 않았고 tyramine은 HH12, HR254, KR110 균주는 각각 6.09, 3.68, 6.30 mg/L로 검출되었다. 선발한 biogenic amines 저감화 균주들의 BAs 생성량을 decarboxylase 고생산 미생물로 사료되는 <TEX>$B.$</TEX> <TEX>$subtilis$</TEX> MC138 균주와 비교해보면 현저히 낮은 수준으로 나타났다. Microorganisms, having the lower decarboxylase activity, among the isolated strains from <TEX>$cheonggukjang$</TEX> and rice-straw in this study were selected by using biogenic amine (BA) media. The selected strains were identified as <TEX>$Bacillus$</TEX> <TEX>$subtilis$</TEX> HH12, <TEX>$B.$</TEX> <TEX>$subtilis$</TEX> HR254, and <TEX>$Paenibacillus$</TEX> <TEX>$barcinonensis$</TEX> KR97, by using 16S rRNA analysis. PCR analysis showed that the histidine decarboxylase (<TEX>$hdc$</TEX>) gene was absent in the HH12, HR254, and KR97 strains. However, PCR analysis showed that the tyrosine decarboxylase (<TEX>$tdc$</TEX>) gene was present in the HH12, HR254, and KR97 strains. Quantitative analysis of the selected strains by using high-performance liquid chromatography showed that histamine was absent in the HH12, HR254, and KR97 strains. However, these 3 strains showed tyramine concentrations of 6.09, 3.68, and 6.30 mg/L, respectively. These strains produced lower concentrations of amines (approximately 7.9, 0, and 9.3% amines in the HH12, HR254, and KR97 strains, respectively) than the <TEX>$B.$</TEX> <TEX>$subtilis$</TEX> MC138 strain, which showed the higher protease activity.