Korea University · Biochemistry, Genetics and Molecular Biology
Professor Jae-Hyung Mah's research lab focuses on microbial physiology, food safety, and biodegradable materials, with a strong emphasis on understanding and controlling microbial processes in food systems. The lab investigates the molecular mechanisms of sporulation in pathogenic fungi and bacteria, particularly *Aspergillus fumigatus* and *Bacillus* species, to develop strategies for preventing foodborne infections. It also explores bioactive compounds such as levan and antimicrobial peptides like nisin for their applications in food preservation and sustainable packaging. Additionally, the lab addresses food safety concerns related to biogenic amines in fermented foods, especially traditional Asian fermented products.
Figures are computed from collected data and may differ slightly.
The opportunistic human pathogen Aspergillus fumigatus produces a large quantity of asexual spores (conidia), which are the primary agent causing invasive aspergillosis in immunocompromised patients. We investigated the mechanisms controlling asexual sporulation (conidiation) in A. fumigatus via examining functions of four key regulators, GpaA (Galpha), AfFlbA (RGS), AfFluG, and AfBrlA, previously studied in Aspergillus nidulans. Expression analyses of gpaA, AfflbA, AffluG, AfbrlA, and AfwetA th
Fermented soybean foods possess significant health-promoting effects and are consumed worldwide, especially within Asia, but less attention has been paid to the safety of the foods. Since fermented soybean foods contain abundant amino acids and biogenic amine-producing microorganisms, it is necessary to understand the presence of biogenic amines in the foods. The amounts of biogenic amines in most products have been reported to be within safe levels. Conversely, certain products contain vasoacti
Biodegradable poly(butylene adipate-co-terephthalate) (PBAT) films incorporated with nisin were prepared with concentrations of 0, 1000, 3000, and 5000 international units per cm(2) (IU/cm(2)). All the films with nisin inhibited Listeria innocua, and generated inhibition zones with diameters ranging from 14 to 17 mm. The water vapor permeability and oxygen permeability after the addition of nisin ranged from 3.05 to 3.61 x 10(11) g m m(-2) s(-1) Pa(-1) and from 4.80 x 10(7) to 11.26 x 10(7) mL.m
Summary The objective of this study was to investigate the antibacterial activity of levan compounds, including high‐molecular‐weight levan, low‐molecular‐weight levan and difructose dianhydride IV ( DFA IV ). The levans exhibited broad antibacterial spectra against foodborne pathogenic bacteria, in a concentration‐dependent manner. From comparison with simple saccharides, often regarded as by‐products of levan production, it turned out that the antibacterial activity of levans was primarily cau
In this study, biogenic amine content in two types of fermented radish kimchi (<i>Kkakdugi</i> and <i>Chonggak</i> kimchi) was determined by high performance liquid chromatography (HPLC). While most samples had low levels of biogenic amines, some samples contained histamine content over the toxicity limit. Additionally, significant amounts of total biogenic amines were detected in certain samples due to high levels of putrefactive amines. As one of the significant factors influencing biogenic am
Spores are resistant against many extreme conditions including the disinfection and sterilization methods used in the food industry. Selective prevention of sporulation of <i>Bacillus</i> species is an ongoing challenge for food scientists and fermentation technologists. This study was conducted to evaluate the effects of single and combined supplementation of calcium and manganese on sporulation of common pathogenic and food spoilage <i>Bacillus</i> species: <i>B</i>. <i>cereus</i>, <i>B</i>. <
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