• Journal of Microbiology and Biotechnology
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• 제28권6호
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• pp.1030-1036
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• 2018

Bacillus strains produce various types of antibiotics, and random mutagenesis has traditionally been used to overproduce these natural metabolites. However, this method leads to the accumulation of unwanted mutations in the genome. Here, we rationally designed a single nucleotide substitution in the degU gene to generate a B. subtilis strain displaying increased plipastatin production in a foreign DNA-free manner. The mutant strain (BS1028u) showed improved antifungal activity against Pythium ultimum. Notably, pps operon deletion in BS1028u resulted in complete loss of antifungal activity, suggesting that the antifungal activity strongly depends on the expression of the pps operon. Quantitative real-time PCR and lacZ assays showed that the point mutation resulted in 2-fold increased pps operon expression, which caused the increase in antifungal activity. Likewise, commercial Bacillus strains can be improved to display higher antifungal activity by rationally designed simple modifications of their genome, rendering them more efficient biocontrol agents.

• 미생물학회지
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• 제53권1호
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• pp.55-57
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• 2017

한국 발효식품의 보존성을 높이기 위한 스타터 균주를 얻기 위하여 고추장에서 Bacillus subtilis BS16045를 분리하였다. B. subtilis BS16045에 대한 유전체 분석을 실시하였으며, G+C 비율이 43.6%인 4,165,121 bp 크기의 염기서열을 얻었다. 또한 이 유전체로부터 항진균 및 항균 활성에 연관이 있는 surfactin, kanosamine, bacillaene, plipastatin, subtilosin A, bacilysin 생산 유전자들을 확인하였다. 이러한 결과들을 통해 B. subtilis BS16045는 장류 제조시설에서 유해균의 오염문제를 해결할 수 있는 스타터로 이용될 수 있을 것으로 보인다.