• 한국키틴키토산학회지
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• 제23권4호
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• pp.285-292
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• 2018

음식물쓰레기 분해용 균주를 선발하기 위하여 전통발효식품과 토양으로부터 내염성, 내열성을 갖는 균주 분리를 시도하였으며, protease, amylase, cellulase 및 lipase의 효소활성도를 평가하였다. 5% NA 배지에서 분리된 균주는 212종이었으며, 전통발효식품의 경우 4가지 효소활성을 가지고, 토양의 경우 2가지 이상의 효소활성을 가지며, 억제환이 15 mm 이상의 크기를 지닌 79종의 균주를 우선 선발하였다. 선발된 균주를 대상으로 분자유전학적 동정을 진행한 결과, 중복성을 배제하여 11종의 균주를 최종적으로 선발하여 혼합균주로 사용하였다. 혼합균주의 최적 배양조건으로는 배양시간은 24시간, 배양온도는 $30^{\circ}C$ 그리고 pH의 최적 조건은 7.0 부근인 것으로 확인되었다. 최적배양된 혼합균주 처리에 따른 음식물쓰레기 분해능 평가 결과 멸균수 첨가군은 10 mesh ($2000{\mu}m$)에서 103 g, 혼합균주 첨가군은 10 mesh ($2000{\mu}m$)에서 18 g인 것으로 보아 혼합균주로 나타나 음식물의 고형분의 입자가 액상으로 분해되었음을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제24권5호
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• pp.648-660
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• 2014

Doenjang, a traditional Korean fermented soybean paste, is made by mixing and ripening meju with high salt brine (approximately 18%). Meju is a naturally fermented soybean block prepared by soaking, steaming, and molding soybean. To understand living bacterial community migration and the roles of bacteria in the manufacturing process of doenjang, the diversity of culturable bacteria in meju and doenjang was examined using media supplemented with NaCl, and some physiological activities of predominant isolates were determined. Bacilli were the major bacteria involved throughout the entire manufacturing process from meju to doenjang; some of these bacteria might be present as spores during the doenjang ripening process. Bacillus siamensis was the most populous species of the genus, and Bacillus licheniformis exhibited sufficient salt tolerance to maintain its growth during doenjang ripening. Enterococcus faecalis and Enterococcus faecium, the major lactic acid bacteria (LAB) identified in this study, did not continue to grow under high NaCl conditions in doenjang. Enterococci and certain species of coagulase-negative staphylococci (CNS) were the predominant acid-producing bacteria in meju fermentation, whereas Tetragenococcus halophilus and CNS were the major acid-producing bacteria in doenjang fermentation. We conclude that bacilli, LAB, and CNS may be the major bacterial groups involved in meju fermentation and that these bacterial communities undergo a shift toward salt-tolerant bacilli, CNS, and T. halophilus during the doenjang fermentation process.

• 한국미생물·생명공학회지
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• 제47권1호
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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.

• 식물병연구
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• 제29권2호
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• pp.188-192
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• 2023

식물병 또는 비생물적 스트레스를 감소시키는 것으로 보고된 세균 4종(HS1, H30-3, KJ40 와 BC42)이 Colletotrichum orbiculare 에 의한 오이 탄저병, Acidovorax citrulli에 의한 과실썩음병, Fusarium oxysporum에 의한 오이 덩굴쪼김병에 대한 병 억제 효과가 있는지 검정하였다. HS1, H30-3, KJ40 와 BC42를 토양에 관주처리 할 경우 유도저항성에 의해 오이 탄저병이 감소하였고, KJ40와 BC42는 A. citrulli의 발병을, BC42는 오이 덩굴쪼김병을 억제하였다. 따라서, KJ40은건조피해저감뿐만아니라유도저항성에의 한 오이 탄저병 억제 및 A. citrulli에 의한 병발생 감소효과를 가지며, BC42는 오이 탄저병, A. citrulli와 F. oxysporum에 병을 모두 억제하는 것으로 보아 넓은 범위의 적용 범위를 갖는 생물적 방제제 자원으로 활용할 수 있을 것이다.

• Journal of Ginseng Research
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• 제40권2호
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• pp.97-104
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• 2016

Background: Rhizobacteria play an important role in plant defense and could be promising sources of biocontrol agents. This study aimed to screen antagonistic bacteria and develop a biocontrol system for root rot complex of Panax notoginseng. Methods: Pure-culture methods were used to isolate bacteria from the rhizosphere soil of notoginseng plants. The identification of isolates was based on the analysis of 16S ribosomal RNA (rRNA) sequences. Results: A total of 279 bacteria were obtained from rhizosphere soils of healthy and root-rot notoginseng plants, and uncultivated soil. Among all the isolates, 88 showed antagonistic activity to at least one of three phytopathogenic fungi, Fusarium oxysporum, Fusarium solani, and Phoma herbarum mainly causing root rot disease of P. notoginseng. Based on the 16S rRNA sequencing, the antagonistic bacteria were characterized into four clusters, Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetesi. The genus Bacillus was the most frequently isolated, and Bacillus siamensis (Hs02), Bacillus atrophaeus (Hs09) showed strong antagonistic activity to the three pathogens. The distribution pattern differed in soil types, genera Achromobacter, Acidovorax, Brevibacterium, Brevundimonas, Flavimonas, and Streptomyces were only found in rhizosphere of healthy plants, while Delftia, Leclercia, Brevibacillus, Microbacterium, Pantoea, Rhizobium, and Stenotrophomonas only exist in soil of diseased plant, and Acinetobacter only exist in uncultivated soil. Conclusion: The results suggest that diverse bacteria exist in the P. notoginseng rhizosphere soil, with differences in community in the same field, and antagonistic isolates may be good potential biological control agent for the notoginseng root-rot diseases caused by F. oxysporum, Fusarium solani, and Panax herbarum.