Ha-Kun Kim

Comparison of Microbial Diversity of Korean Commercial Makgeolli Showing High β-Glucan Content and High Antihypertensive Activity, Respectively

We measured physiological functionalities, including antihypertensive angiotensin I-converting enzyme inhibitory activity and immun-stimulating β-glucan content for sixty kinds of Makgeolli that is commercially available from the market. As a result, we selected R-12 commercial raw Makgeolli, with a high content of immuno-stimulating β-glucan, and R-14 commercial raw Makgeolli, exhibiting high antihypertensive activity. Due to the similarities in their overall physicochemical properties and raw materials used for fermentation, we compared the microbial flora in order to investigate the reason for the differences in their functionalities. Nested PCR and denaturing gradient gel electrophoresis for yeasts and bacteria were performed for analysis of microbial diversity of two different kinds of Makgeolli (i.e., R-12, R-14), which showed immuno-stimulating β-glucan content and exhibited a very high level of antihypertensive activity, respectively. Analysis of the 18S rDNA amplicon revealed a major presence of the yeast strain Pichia burtonii in every Makgeolli sample. Analysis of the 16S rDNA amplicon revealed a predominance of lactic acid bacteria, and the most frequent lactic acid bacteria were Lactobacillus ingluviei, L. fermentum, and L. harbinensis, and Lactobacillus sp. Among these, L. harbinensis was detected only in R-12 and L. ingluviei was found only in R-14. Different functionalities from the individual commercially available Makgeolli may be attributed to actions of different microbial flora during fermentation.

Isolation and Identification of Yeasts from Wild Flowers in Gyejoksan, Oseosan and Beakamsan of Korea

Yeasts isolated from wild flowers of Gyejoksan in Daejeon city, Oseosan in Chungchungnamdo, and Baekamsan in Jeollabukdo, Korea were identified by comparison of nucleotide sequences for PCR-amplified D1/D2 region of 26S rDNA or internal transcribed spacer (ITS) 1 and 2 including 5.8S rDNA using BLAST. Twelve yeast strains of ten species and seventeen yeast strains of ten species were isolated from wild flowers of Gyejoksan and Oseosan, respectively. And thirty seven yeast strains of twenty four species were isolated from wild flowers of Baekamsan. Total thirty four yeast species were isolated from three different sample collection areas, but only nine species were overlapped from the at least two different sampling areas: Cryptococcus sp., Cryptococcus aureus, Cryptococcus flavescens, Cryptococcus flavus, Metschnikowia sp., Pseudozyma aphidis, Rhodotorula glutinis, Sporobolomyces carnicolor, and Sporobolomyces ruberrimus. Among them only Cryptococcus aureus was occurred from all three different collection sites. Other twenty five species were restricted to specific collection site suggesting that each area has distinctive yeast flora.

Isolation and Identification of Yeasts from Wild Flowers of Daejeon City and Chungcheongnam-do in Korea

Total 50 species, 80 strains: Eighty strains of yeasts were isolated from wild flowers of Daejeon city and its surroundings in Korea. Isolated yeasts were identified by comparison of their PCR-amplified 18s rDNA V3 region or internal transcribed spacer-2 (ITS-2) genes with BLAST database. Among them, 32 species, 54 strains of yeasts were isolated and identified from wild flowers of Daejeon city, and Cryptococcus species were dominant yeasts. Furthermore, 18 species, 26 strains of yeasts were isolated and identified from wild flowers of Geumsan-gun and Nonsan-gun, Chungcheongnam-do in Korea, and also Candida species and Pseudozyma species were dominant yeasts.

Isolation and Diversity of Yeasts from Wild Flowers in Ulleungdo and Yokjido, Korea

Various yeasts from wild flowers of Ulleungdo in Gyeongsangbuk-do and Yokjido in Gyeongsangnam-do, Korea were isolated and identified by comparison of nucleotide sequences for PCR-amplified D1/D2 region of 26S rDNA using BLAST. Forty eight yeast strains of twenty two species and sixty yeast strains of twenty five species were isolated from wild flowers of Ulleungdo and Yokjido, respectively. Only seven species were overlapped from the two different islands areas: Cryptococcus albidus, Cryptococcus laurentii, Metschnikowia reukafii, Pichia scolyti, Rhodotorula glutinis, Rhodotorula graminis and Rhodotorula mucilaginosa. Among forty species from two different islands, other thirty three species were restricted to specific collection site suggesting that each area has distinctive yeast flora.

Production and characterization of keratinase fromParacoccus sp. WJ-98

A bacterial strain WJ-98 found to produce active extracellular keratinase was isolated from the soil of a poultry factory. It was identified asParacoccus sp. based on its 16S rRNA sequence analysis, morphological and physiological characteristics. The optimal culture conditions for the production of keratinase byParacoccus sp. WJ-98 were investigated. The optimal medium composition for keratinase production was determined to be 1.0% keratin, 0.05% urea and NaCl, 0.03% K2HPO4, 0.04% KH2PO4, and 0.01% MgCl2·6H2O. Optimal initial pH and temperature for the production of keratinase were 7.5 and 37°C, respectively. The maximum keratinase production of 90 U/mL was reached after 84 h of cultivation under the optimal culturing conditions. The keratinase fromParacoccus sp. WJ-98 was partially purified from a culture broth by using ammonium sulfate precipitation, ion-exchange chromatography on DEAE-cellulose, followed by gel filtration chromatography on Sephadex G-75. Optimum pH and temperature for the enzyme reaction were pH 6.8 and 50°C, respectively and the enzymes were stable in the pH range from 6.0 to 8.0 and below 50°C. The enzyme activity was significantly inhibited by EDTA, Zn2+ and Hg2+. Inquiry into the characteristics of keratinase production from these bacteria may yield useful agricultural feed processing applications.

Screening of Fungal Nuruk and Yeast for Brewing of Gugija-Liriope tuber Traditional Rice Wine and Optimal Fermentation Condition

To develop new functional traditional rice wines using Gugija and Liriope tuber as raw materials, screenings of optimal fungal nuruk and alcohol fermentative yeast for brewing of Gugija-L. tuber traditional rice wine were performed with investigation of optimal fermentation condition. Finally, we selected commercial SJ nuruk and Saccharomyces cerevisiae C-2 as optimal nuruk and yeast for Gugija-L. tuber traditional rice wine. Furthermore, a new antihypertensive and anti-gout Gugija-L. tuber traditional rice wine was produced when 3% of Jangmyong Gugija and L. tuber No.1 were added into cooked rice and then fermented at 25oC for 5 days with SJ nuruk and S. cerevisiae C-2.

Isolation and Diversity of Yeasts from Fruits and Flowers of Orchard in Sinam-myeon of Yesan-gun, Chungcheongnam-do, Korea

Several kinds of yeasts from fruits and flowers of orchard in Yesan-gun of Chungcheongnam-do, Korea were isolated and identified by comparison of nucleotide sequences for PCR-amplified D1/D2 region of 26S rDNA using BLAST. Fourty eight yeast strains of twenty five species and one hundred eight yeast strains of fourty eight species were isolated from fruits and flowers of orchard in Sinam-myeon of Yesan-gun, Chungcheongnam-do, respectively. Among total one hundred fifty-six yeast strains, only sixteen species were overlapped from fruits and flowers.

Note on Newly Isolated Yeasts from Wild Flowers in Daejeon City, Korea

We report morphological and physiological characteristics of newly isolated six kinds of yeasts which are new in Korean mycoflora. The yeasts were isolated from wild flowers in Daejeon city, Korea and identified by molecular analysis of the amplified internal transcribed space rDNA sequence or partial 18S rDNA sequence. Species of isolates were identified as Kuraishia capsulate, Lodderomyces elongisporus, Pseudozyma antarctica, Starmerella bombicola.

Yeasts Associated with Fruits and Blossoms Collected from Hanbat Arboretum, Daejeon, Korea

Yeasts are common inhabitants of the phyllosphere, but our knowledge of their diversity in various fruits and blossoms are limited. We collected different kinds of blossoms and unripened fruits from Hanbat arboretum, Daejeon, Korea at the year of 2013. Yeasts were isolated by plating of suspensions prepared for collected samples onto YPD medium containing antibiotics. BLAST searches were subsequently performed for the comparison of the partially determined sequences of D1/D2 domain of 26S rDNA. As a result, we isolated 57 yeast strains of 31 species from 29 different kinds of blossoms and 6 kinds of fruits samples. We found huge differences in yeast flora depending on the sample collection season.

Isolation and Identification of Yeasts from Wild Flowers Collected around Jangseong Lake in Jeollanam-do, Republic of Korea, and Characterization of the Unrecorded Yeast Bullera coprosmaensis.

Abstract Several types of yeasts were isolated from wild flowers around Jangseong Lake in Jeollanam-do, Republic of Korea and identified by comparing the nucleotide sequences of the PCR amplicons for the D1/D2 variable domain of the 26S ribosomal DNA using Basic Local Alignment Search Tool (BLAST) analysis. In total, 60 strains from 18 species were isolated, and Pseudozyma spp. (27 strains), which included Pseudozyma rugulosa (7 strains) and Pseudozyma aphidis (6 strains), was dominant species. Among the 60 strains, Bullera coprosmaensis JS00600 represented a newly recorded yeast strain in Korea, and its microbiological characteristics were investigated. The yeast cell has an oval-shaped morphology measuring 1.4 × 1.7 μm in size. Bullera coprosmaensis JS00600 is an asporous yeast that exhibits no pseudomycelium formation. It grew well in vitamin-free medium as well as in yeast extract-malt extract broth and yeast extract-peptone-dextrose (YPD) broth, and it is halotolerant growing in 10% NaCl-containing YPD broth.