• Asian-Australasian Journal of Animal Sciences
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• v.13 no.8
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• pp.1173-1177
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• 2000

This study investigated the nitrate reduction ability of Micrococcaceae on pigment formation in Chinese- style sausage. One hundred ppm sodium nitrite and 150 ppm sodium nitrate was added asepticly to ground pork which was then inoculated with $10^7CFU/g$ of either Micrococcus varians, Staphylococcus carnosus or Staphylococcus xylosus. All samples were cured at $20{^{\circ}C}$ or $30{^{\circ}C}$ for 3 days and then color, residue nitrite, nitrosyl pigment and residue nitrate were determined. The results indicated that samples inoculated with S. xylosus had higher a- and b- values due to nitrate reduction and pigment production after 3 days curing and these values were higher at the higher curing temperature. The nitrosyl pigment of the samples with S. xylosus had highest values after 3 days curing at both $20{^{\circ}C}$ and $30{^{\circ}C}$. However, sample inoculated with S. carnosus and S. xylosus had lower nitrate contents than the sample inoculated with M. varians. At $30{^{\circ}C}$ as well as S. carnosus and M. varians had a stronger decreasing in nitrate concentration during curing at $20{^{\circ}C}$. Moreover, samples inoculated with S. xylosus and S. carnosus had a higher residual nitrite content during curing at $20{^{\circ}C}$ or $30{^{\circ}C}$. In conclusion, two Staphylococci strains tested were most optimum starter cultures for improving pigment formation during Chinese-style sausage curing.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.11
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• pp.1858-1865
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• 2020

Objective: The microbiota of dairy cow milk varies with the season, and this accounts in part for the seasonal variation in mastitis-causing bacteria and milk spoilage. The microbiota of the cowshed may be the most important factor because the teats of a dairy cow contact bedding material when the cow is resting. The objectives of the present study were to determine whether the microbiota of the milk and the cowshed vary between seasons, and to elucidate the relationship between the microbiota. Methods: We used 16S rRNA gene amplicon sequencing to investigate the microbiota of milk, feces, bedding, and airborne dust collected at a dairy farm during summer and winter. Results: The seasonal differences in the milk yield and milk composition were marginal. The fecal microbiota was stable across the two seasons. Many bacterial taxa of the bedding and airborne dust microbiota exhibited distinctive seasonal variation. In the milk microbiota, the abundances of Staphylococcaceae, Bacillaceae, Streptococcaceae, Microbacteriaceae, and Micrococcaceae were affected by the seasons; however, only Micrococcaceae had the same seasonal variation pattern as the bedding and airborne dust microbiota. Nevertheless, canonical analysis of principle coordinates revealed a distinctive group comprising the milk, bedding, and airborne dust microbiota. Conclusion: Although the milk microbiota is related to the bedding and airborne dust microbiota, the relationship may not account for the seasonal variation in the milk microbiota. Some major bacterial families stably found in the bedding and airborne dust microbiota, e.g., Staphylococcaceae, Moraxellaceae, Ruminococcaceae, and Bacteroidaceae, may have greater influences than those that varied between seasons.

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.67-72
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• 2014

Minimal broth containing nicotine as a sole carbon source (MB/N) was used to isolate novel nicotine-degrading bacterial strains from tobacco plants and field soils. Comparative analysis of 16S rRNA gene sequence, phenotypic test and morphological tests showed that the position of these isolates were in the genus Arthrobacter of the family Micrococcaceae. The highest 16S rRNA gene sequence similarity of the isolate NU11 and NU15 to type strains in the genus Arthrobacter were Arthrobacter equi (98.2%) which was presumably a novel strain and Arthrobacter nicotinovorans (99.8%), respectively. Both strain NU11 and NU15 showed rod shaped, Gram-positive characteristics and catalase activity, but did not show oxidase activity. The novel strain NU11 was found to degrade efficiently nicotine in MB/N medium by the analysis of UV absorption spectra and could be used as an organism in bioremediation technique.

• Journal of Life Science
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• v.28 no.12
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• pp.1477-1488
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• 2018

This study investigated the muscles, intestines, and gonads of Sulculus diversicolor supertexta to examine the diversity of microbial communities within examples collected from the Jeju Coast. Using different media, initial pure isolation in MA, 1% BHIA, and 1% TSA indicated that the muscles, intestines, and gonads supported more communities, respectively. In analysis of relative similarity with 16s rRNA sequencing, 190 pure colonies were isolated, and further analysis with NBLAST identified 71 species, 39 genera, 25 families, and five phyla. Homogeny with the reference strain was 91-100%. Microbial communities in S. supertexta consisted of gamma and alpha Proteobacteria (48%), Actinobacteria (32.5%), Firmicutes (16.9%), Deinococcus-Thermus (1.3%), and Bacteroides (1.3%). In all tissue, Psychrobacter cibarius in Moraxellaceae was dominant. Alteromonadaceae, Enterobacteriaceae, Pasturellaceae, Moraxellaceae, Rhodobacteraceae, Geminicoccaceae, Dietziaceae, Intrasporangiaceae, Microbacteriaceae, Micrococcaceae, Micromonosporaceae, Streptomycetaceae, Aerococcaceae, Bacillaceae, Paenibacillaceae, Planococcaceae, and Staphylcoccaceae were commonly isolated across all tissues, and Flavobacteriaceae, Corynebacteriaceae, Yesiniaceae, Vibrionaceae, Hahellaceae, Pseudomonadaceae were also identified from the intestines. In microbial monitoring of four harmful bacteria, Streptomyces albus (96%) showed antibacterial activity against all four strains, and Agrococcus baldri (99%) and Psychrobacter nivimaris (99%) presented against E. Coli and E. aerogens. In addition, some strains with low homogeny were isolated and further experiments are therefore required, for example to refine the antimicrobial substances including new strain investigations. These additional experiments would aim to establish generic resources for the microbial communities in S. Supertexta and provide basic data for applied microbiological research.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.3
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• pp.376-380
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• 2000

This study was conducted to investigate protein and carbohydrate utilization of Micrococcus varians, Staphylococcus carnosus and Staphylococcus xylosus. Sensitivity to pH, sodium chloride, potassium sorbate and sodium nitrite of these strains was also determined. In Chinese-style beaker sausage manufacturing, the growth rate of these strains during the curing period ($20^{\circ}C$ and $30^{\circ}C$) was evaluated. The results indicated that no strains could hydrolyze azo-casein and sarcoplasmic protein and only S. xylosus could hydrolyze gelatin at $30^{\circ}C$. All of these strains could oxidize and ferment fructose and mannitol. S. carnosus and S. xylosus could slightly oxidize lactose and utilize citrate. Arabinose was oxidized by S. xylosus and sorbitol was oxidized by S. carnosus. Growth of M. varians was restricted at pH 5.0 and S. carnosus and S. xylosus were restricted at pH 4.5. S. xylosus and S. carnosus were able to grow with 0.1~0.5% potassium sorbate, 50~200 ppm sodium nitrite or 1~15% sodium chloride. S. xylosus had a higher growth rate than the other strains. Staphylococcus species grew well during curing period of Chinese-style beaker sausage then followed by Micrococcaceae.

• Journal of Species Research
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• v.11 no.1
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• pp.1-9
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• 2022

The phylum Actinobacteria includes many groups of aerobic, Gram-stain-positive, rod, or filamentous shaped bacteria. Actinobacteria are known for multicellular differentiation in some groups, and also for production of various secondary metabolites such as antibiotics. During a series of extensive surveys of indigenous prokaryotic species diversity in Korea, bacterial strains belonging to Actinobacteria were isolated from various sources of terrestrial environments. A total of 21 bacterial strains, belonging to 10 genera in 8 families, were isolated as unrecorded species in Korea. Among them, 11 were assigned to the family Streptomycetaceae, two species assigned to each of the families Microbacteriaceae, Mycobacteriaceae and Nocardioidaceae, and one species assigned to each of the families Euzebyaceae, Corynebacteriaceae, Micrococcaceae and Intrasporangiaceae. At the genus level, Streptomyces (10 species) was the most abundant, followed by Microbacterium and Mycolicibacterium(2 species each), and one species in each of the genera Corynebacterium, Euzebya, Arthrobacter, Terracoccus, Kribbella, Nocardioides and Yinghuangia. The detailed descriptions of each unrecorded species are provided.

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.444-449
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• 1992

A total of 858 heterotrohic bacteria were isolated and analyzed hy numerical method to investigate the heterotrophic hacterial community structure in Naktong Estuary. Although the values of H' (Shannon's diversity index). ranged between 1.54 and 3.49. were similar with those of the data hefore the construction of Naktong River barrage, however J' (evenness index. 0.31-0.80) was reduced. Physiological tolerance index for water temperature ($P_{s}$) was high at St.l and 2 whose depthes arc shallower than the other stations. and indices for pH ($P_{h}$) and salinity ($P_{s}$) were high at St. 2. 3. 4 where freshwater and seawater arc mixed. The predominant clusters were identified as Aeromonas. Vihrio. Pseudomonas. Acinelobacter-Morexella. Alcaligenes. Flavobacterium. Micrococcaccae. and Enterohacteriaceae. The kinds nf the isolates were similar with the previous result. hut the dominant genus was changed. These results suggest that the environmental changes in Naktong Estuary affect the hacterial physiological adaptation rather than the composition of heterotrophic hactcrial community.

• Journal of Species Research
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• v.9 no.2
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• pp.85-104
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• 2020

In 2019, after a comprehensive investigation of indigenous prokaryotic species in Korea, a total of 12 bacterial strains assigned to the phylum Proteobacteria were isolated from soil. With the high 16S rRNA gene sequence similarity (>98.8%) and formation of a robust phylogenetic clade with the closest species, it was determined that each strain belonged to independent, predefined bacterial species. This study identified two species in the family Burkholderiaceae, one species in the family Comamonadaceae, two species in the family Oxalobacteraceae, one species in the family Micrococcaceae, one species in the family Bradyrhizobiaceae, one species in the family Methylobacteriaceae, one species in the family Rhizobiaceae, one species in the family Rhodocyclaceae, and one species in the family Sphingomonadaceae. There is no official report about these 12 species in Korea, so are described as unreported bacterial species in Korea in this study. Gram reaction, basic biochemical characteristics, colony, and cell morphology are also described in the species description section.

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.125-131
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• 2019

We have isolated and identified 72 bacterial strains from four bentonite samples collected at the mining areas located in Gyeongsangbuk-do, Republic of Korea, and measured their hydrolytic enzyme (${\alpha}$-amylase, protease, and cellulase) activities to identify the isolates with industrial-use potential. Most of the isolates belonged to the Bacillaceae, with minor portions being from the Paenibacillaceae, Micrococcaceae, and Bacillales Family XII at the family level. Of the strains isolated, 33 had extracellular ${\alpha}$-amylase activity, 30 strains produced cellulase, and 35 strains produced protease. Strain MBLB1268, having the highest ${\alpha}$-amylase activity, was identified as Bacillus siamensis ($0.38{\pm}0.06U/ml$). Bacillus tequilensis MBLB1223, isolated from Byi33-b, showed the highest cellulase activity ($0.26{\pm} 0.04U/ml$), whereas Bacillus wiedmannii MBLB1197, isolated from Zdb130-b, exhibited the highest protease activity ($54.99{\pm}0.78U/ml$). These findings show that diverse bacteria of the Bacillaceae family adhere to and exist in bentonite and are potential sources of industrially useful hydrolytic enzymes.

• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.219-227
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• 2023

Lettuce is one of the most consumed vegetables worldwide. However, it has potential risks associated with pathogenic bacterial contamination because it is usually consumed raw. In this study, we investigated the changes in the bacterial community on lettuce (Lactuca sativa L.) in Chungcheong-do, South Korea, and the prevalence of foodborne pathogens on lettuce in different seasons using 16S rRNA gene-based sequencing. Our data revealed that the Shannon diversity index showed the same tendency in term of the number of OTUs, with the index being greatest for summer samples in comparison to other seasons. Moreover, the microbial communities were significantly different between the four seasons. The relative abundance of Actinobacteriota varied according to the season. Family Micrococcaceae was most dominant in all samples except summer, and Rhizobiaceae was predominant in the microbiome of the summer sample. At the genus level, the relative abundance of Bacillus was greatest in spring samples, whereas Pseudomonas was greatest in winter samples. Potential pathogens, such as Staphylococcus and Clostridium, were detected with low relative abundance in all lettuce samples. We also performed metagenome shotgun sequencing analysis on the selected summer and winter samples, which were expected to be contaminated with foodborne pathogens, to support 16S rRNA gene-based sequencing dataset. Moreover, we could detect seasonal biomarkers and microbial association networks of microbiota on lettuce samples. Our results suggest that seasonal characteristics of lettuce microbial communities, which include diverse potential pathogens, can be used as basic data for food safety management to predict and prevent future outbreaks.