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Microbiology and Biotechnology Letters


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Molecular and Cellular Microbiology (MCM)  |  Microbial Genetics, Physiology and Metabolism

Microbiol. Biotechnol. Lett. 2021; 49(2): 255-263

Received: December 15, 2020; Accepted: January 4, 2021

메주 유래 Enterococcus faecium 균주의 기능적 특성 및 안전성

Technological Characteristics and Safety of Enterococcus faecium Isolates from Meju, a Traditional Korean Fermented Soybean Food

Yeongmin Oh 1, Haram Kong 1, Do-Won Jeong 2 and Jong-Hoon Lee 1*

1Department of Food Science and Biotechnology, Kyonggi University, Suwon 16227, Republic of Korea 2Department of Food and Nutrition, Dongduk Women’s University, Seoul 02748, Republic of Korea

Correspondence to :
Jong-Hoon Lee,

In this study, we assessed the technological characteristics and safety of 88 Enterococcus faecium strains isolated from meju; the strains possess the glutamate decarboxylase gene gadA/B involved in γ-aminobutyric acid production. The study was conducted to evaluate the possibility of introducing E. faecium meju isolates as food fermentation starters. We observed that a NaCl concentration of 6% (w/v) facilitated the growth and acid production of all strains. At a NaCl concentration of 7%, 21 strains (24%) exhibited a low growth rate, 72 strains (82%) a weak acid production, and 16 strains (18%) showed no acid production. All strains exhibited protease activity at a NaCl concentration of 4%. At a NaCl concentration of 5%, 86 strains exhibited weak activity, and one strain showed no protease activity. We could not detect any lipase activity in the investigated strains. None of the strains exhibited an acquired antibiotic resistance to the seven antibiotics tested in the present study, namely ampicillin, chloramphenicol, ciprofloxacin, gentamicin, penicillin G, tetracycline, and vancomycin. We could identify the Enterococcus endocarditis antigen gene efaA and the tyrosine decarboxylase gene tdc contributing to tyramine production, in 88 meju isolates. We could not detect the Enterococcus surface protein gene esp, which is specifically possessed by human-originated E. faecium strains, in any of the 88 strains tested in the study.

Keywords: Meju, Enterococcus faecium, technological characteristic, antibiotic resistance, virulence factor

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