MICROPOP, a microbial laboratory belonging to BIOPOP, studies microbiome including probiotics, gut microbiota, and microbial population. We have performed two main topics: screening of microbial strains with useful phenotypic functions and identifying relationships between the genotypes of the strains and its phenotypes. We aim to improve functional strains and introduce a novel method to understand genetic mechanism of microbes for combining experimental methods and bioinformatical approaches.

❚ Research Topics

1. Strain isolation
• Isolation of lactic acid bacteria from various sources such as dairy products (cheese, yogurt, etc), traditional fermented foods (kimchi, kochujang, doenjang, etc), and fruits/vegetables Strain identification by catalase test, Gram-staining, morphology observation, and 16s rRNA sequencing
2. Improvement of microbial phenotype through ALE
• An adaptive laboratory evolution (ALE) method is an experimental approach frequently used in microbiology to obtain desired phenotypic function during long time selection under specified growth conditions. After applying selective pressure such as high temperature resistance, the microbial strains with improved phenotypic functions are selected through screening, and the causal mutations that confer the improvement are discovered.
• To obtain strains with increased survival rate at 60 ̊C or higher through simple stepwise ALE experiments on Lactobacillus acidophilus, Enterococcus faecium, and Streptococcus thermophiles, which are widely used probiotics
• By applying ALE method on Lactobacillus acidophilus, Enterococcus faecium, and Streptococcus thermophiles, which are widely used probiotics, evolved strains with increased survival rate at 60 ̊C or higher were obtained.
3. Microbial genome analysis
• Whole genome sequencing of microbial genomes with specific phenotypes to discover candidate genes associated with phenotypes Perform comparative genome analysis on the strains before and after ALE to detect genetic factors changed by the selection pressure and analyze the evolutionary pattern
4. Identification of cognitive improvement by probiotic microbes
• To discover valid probiotics to improve cognition such as Lactobacillus, Bifidobacterium
• To investigate cognitive mechanism caused by gut microbiome through brain-gut axis
5. Investigation of Antibiotics resistance for probiotic strains
• Isolation of probiotic strains including lactic acid bacteria, Bifidobacterium from human biological samples and fermented foods.
• Investigation of their phenotypic properties of antibiotics resistance via disk diffusion assay or MIC test.
• Clarification of resistance mechanism and transfer possibility via genomic analysis.

6. Gene editing of lactic acid bacteria using the CRISPR-Cas9 system
• Isolation and identification of lactic acid bacteria (LAB) from human breast milk, feces, and fermented dairy food.
• Screening of LAB for CRISPR-Cas9 and identification of functional and therapeutically relevant genes in selected LAB using whole genome sequencing (WGS).
• Development of gene-edited LAB strains using the CRISPR-Cas9 system to enhance their functionalities as potential biotherapeutics for disease.