Journal of Microbiology

Journal Articles

Medium Chain Length Polyhydroxyalkanoate Production by Engineered Pseudomonas gessardii Using Acetate-formate as Carbon Sources.: Woo Young Kim, Seung-Jin Kim, Hye-Rin Seo, Yoonyong Yang, Jong Seok Lee, Moonsuk Hur, Byoung-Hee Lee, Jong-Geol Kim, Min-Kyu Oh; J. Microbiol. 2024;62(7):569-579. Published online May 3, 2024; DOI: https://doi.org/10.1007/s12275-024-00136-x

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Abstract: Production of medium chain length polyhydroxyalkanoate (mcl-PHA) was attempted using Pseudomonas gessardii NIBRBAC000509957, which was isolated from Sunchang, Jeollabuk-do, Republic of Korea (35°24'27.7"N, 127°09'13.0"E) and effectively utilized acetate and formate as carbon sources. We first evaluated the utilization of acetate as a carbon source, revealing optimal growth at 5 g/L acetate. Then, formate was supplied to the acetate minimal medium as a carbon source to enhance cell growth. After overexpressing the acetate and formate assimilation pathway enzymes, this strain grew at a significantly higher rate in the medium. As this strain naturally produces PHA, it was further engineered metabolically to enhance mcl-PHA production. The engineered strain produced 0.40 g/L of mcl-PHA with a biomass content of 30.43% in fed-batch fermentation. Overall, this strain can be further developed to convert acetate and formate into valuable products.

Sporosarcina jeotgali sp. nov., Sporosarcina oncorhynchi sp. nov., and Sporosarcina trichiuri sp. nov., Isolated from Jeotgal, a Traditional Korean Fermented Seafood.: Ah-In Yang, Bora Kim, Sung-Hong Joe, Hae-In Joe, Hanna Choe, Ki Hyun Kim, Min Ok Jun, Na-Ri Shin; J. Microbiol. 2024;62(4):285-296. Published online April 8, 2024; DOI: https://doi.org/10.1007/s12275-024-00106-3

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Abstract: Three novel, Gram-stain-positive, obligate aerobic, catalase- and oxidase-positive bacterial strains, designated B2O-1(T), T2O-4(T), and 0.2-SM1T-5(T), were isolated from jeotgal, a traditional Korean fermented seafood. Strains B2O-1(T), T2O-4(T), and 0.2-SM1T-5(T) exhibited distinct colony colors, characterized by pink, yellow, and red opaque circular colonies, respectively. Phylogenetic analysis revealed that three strains formed a paraphyletic clade within the genus Sporosarcina and shared < 99.0% similarity with Sporosarcina aquimarina KCTC 3840(T) and Sporosarcina saromensis KCTC 13119(T) in their 16S rRNA gene sequences. The three strains exhibiting Orthologous Average Nucleotide Identity values < 79.3% and digital DNA-DNA hybridization values < 23.1% within the genus Sporosarcina affirmed their distinctiveness. Strains B2O-1(T), T2O-4(T), and 0.2-SM1T-5(T) contained MK-7 as a sole respiratory menaquinone and A4α type peptidoglycan based on lysine with alanine, glutamic acid, and aspartic acid. The common polar lipids include diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. Strain T2O-4(T) contained one unidentified phospholipid, whereas strain 0.2-SM1T-5(T) contained two unidentified phospholipids. Cellular fatty acid profiles, with C(15:0) anteiso as the major fatty acid, supported the affiliation of the three strains to the genus Sporosarcina. Based on the polyphasic characteristics, strains B2O-1(T) (= KCTC 43506(T) = JCM 36032(T)), T2O-4(T) (= KCTC 43489(T) = JCM 36031(T)), and 0.2-SM1T-5(T) (= KCTC 43519(T) = JCM 36034(T)) represent three novel species within the genus Sporosarcina, named Sporosarcina jeotgali sp. nov., Sporosarcina oncorhynchi sp. nov., and Sporosarcina trichiuri sp. nov., respectively.

Paracoccus jeotgali sp. nov., isolated from Korean salted and fermented shrimp: Juseok Kim , Joon Yong Kim , Hye Seon Song , In-Tae Cha , Seong Woon Roh , Se Hee Lee; J. Microbiol. 2019;57(6):444-449. Published online May 27, 2019; DOI: https://doi.org/10.1007/s12275-019-8704-8

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Abstract: A Gram-stain-negative and facultatively aerobic bacterium, designated as strain CBA4604T, was isolated from a traditional Korean salted and fermented shrimp food (saeu-jeot). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain CBA4604T formed a clearly distinct phyletic lineage from closely related species within the genus Paracoccus. Strain CBA4604T was the most closely related to P. koreensis Ch05T (97.5% 16S rRNA gene sequence similarity) and other type strains (≤ 97.0%). The genome comprised a chromosome and two plasmids of 3,299,166 bp with 66.5% G+C content. The DNA-DNA relatedness values between strain CBA4604T and P. koreensis Ch05T, P. alcaliphilus DSM 8512T, and P. stylophorae KTW-16T were 30.5%, 22.9%, and 16.7%, respectively. Cells of the strain were short rod-shaped and oxidase- and catalase-positive. The growth of strain CBA- 4604T was observed at 10–40°C (optimum, 37°C), pH 6.0–10.0 (optimum, pH 7.0), and in the presence of 0–8.0% (w/v) NaCl (optimum, 0–2.0%). Strain CBA4604T contained ubiquinone 10 as the sole isoprenoid quinone and summed feature 8 (C18:1 ω7c/C18:1 ω6c) and C18:0 as the major cellular fatty acids. The polar lipids consisted of phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phospholipid, an unidentified aminolipid, an unidentified glycolipid, and three unidentified lipids. Based on its phylogenetic, genomic, phenotypic, and chemotaxonomic features, we concluded that strain CBA- 4604T represents a novel species in the genus Paracoccus and we propose the name Paracoccus jeotgali sp. nov. The type strain is CBA4604T (= KACC 19579T = JCM 32510T).

Nano-encapsulation of naringinase produced by Trichoderma longibrachiatum ATCC18648 on thermally stable biopolymers for citrus juice debittering: Manal M. Housseiny , Heba I. Aboelmagd; J. Microbiol. 2019;57(6):521-531. Published online May 27, 2019; DOI: https://doi.org/10.1007/s12275-019-8528-6

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Abstract: Characteristics of naringinase nano-encapsulated forms on different carrier materials (chitosan and alginate polymers) were investigated in this study. Screening of twelve fungal isolates for naringinase production indicated that Trichoderma longibrachiatum was the most promising. Grapefruit rind was used as a substrate containing naringin for naringinase production. TEM micrographs showed that chitosan nano-capsules were applied for the production of morphologically homogeneous enzymatic nano-particles with high enzyme encapsulation efficiency, small asymmetric sizes (from 15.09 to 27.07 nm with the mean of 21.8 nm) and rough surfaces compared to nano-encapsulated naringinase in alginate which showed nano-particle size (from 33.37 to 51.01 nm with the mean of 43.03 nm). It was revealed that the highest naringinase activity was found in case of chitosan nano-capsule naringinase compared to alginate nano-capsule one. Thermogram analysis (TGA) showed that the free enzyme loses about 92% of its weight at approximately 110°C, while the nanoencapsulated ones show more stability at higher temperatures. Conclusively, the nano-capsulation process improves the kinetics and operational stability so could be useful as a debittering agent for various thermal processing applications in citrus juices industries which makes the fruit juice more acceptable and cost-effective to the consumer.

Research Support, Non-U.S. Gov't

NOTE] Halomonas jeotgali sp. nov., a New Moderate Halophilic Bacterium Isolated from a Traditional Fermented Seafood: Min-Soo Kim , Seong Woon Roh , Jin-Woo Bae; J. Microbiol. 2010;48(3):404-410. Published online June 23, 2010; DOI: https://doi.org/10.1007/s12275-010-0032-y

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27 Citations

Abstract: A moderate halophilic, Gram-negative, non-motile, rod-shape, and aerobe designated as strain HwaT was isolated from traditional fermented Korean seafood, which presented as a single cell or paired cells. Optimal growth occurred at 25°C in 10% (w/v) salts at pH 7.0-8.0; however, growth occurred in a temperature range of 10-32°C, a salts concentration of 5-25% (w/v) and pH 5.0-10.0. Tests for oxidase and catalase were positive. The cells produced poly-β-hydroxybutyric acid, but not exopolysaccharide. Based on the 16S rRNA gene sequence, not only was there low similarity between strain HwaT and all other species (94.1% similarity with H. subglaciescola DSM 4683T, 94.0% similarity with H. sulfidaeris Esulfide1T, 93.6% similarity with H. cerina SP4T and 93.0% similarity with H. halodurans DSM 5160T), but the phylogenetic analysis revealed that the isolate may be classified as a novel species belonging to the genus Halomonas in the class Gammaproteobacteria. The predominant fatty acids of strain HwaT were C18:1 ω7c, C16:0, C12:0 3-OH and C16:1 ω7c/C15:0 iso 2-OH. The DNA G+C content was calculated as 61.7 mol%. Based on phenotypic, genotypic, and phylogenetic characteristics, it is proposed that the strain designated as HwaT be assigned to the genus Halomonas as Halomonas jeotgali sp. nov. (=KCTC 22487T =JCM 15645T).

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