Pseudomonas fluorescens BB2 균주가 생산하는 단백질성 항생물질에 의한 효모 Candida 생육 억제

Abstract

Department of Biology Education, Seowon University, Choongbuk 28674, Republic of Korea(Received November 23, 2015; Accepted December 24, 2015)ABSTRACT: The bacterial strain that was isolated from chinese cabbage rhizosphere, showed inhibition of yeast growth. This strain was identified as Pseudomonas fluorescens BB2 by API 20NE test and 16S rRNA gene sequence analysis. P. fluorescens BB2 strain produced antibiotics against yeast as a secondary metabolite effectively when the culture was carried out in YM medium with 3% glucose a t 20°C.The protein antibiotic of BB2 strain which was concentrated by ammonium sulfate precipitation and n-butanol extraction inhibited the growth of yeast with the minimal inhibitory concentration of 10 μg/ml against Candida albicans KCTC 7965, and the growth of yeast was completely inhibited at 80 μg/ml. The hydrophilic fraction of n-butanol extraction inhibited the growth of Bacillus cereus ATCC 21366, showed orange halo on chrome azurol S plate, which means the fraction contained iron chelating siderophore. The results of crystal violet uptake through the cell membrane showed that membrane permeability was increased about 9% than control, when the concentration of hydrophobic antibiotic against yeast C. albicans was 60 μg/ml. As a result, the antibiotic produced by P. fluorescens BB2 against yeast Candida is considered antimicrobial peptide, and this is the first report in the genus Pseudomonas .Key words: Pseudomonas fluorescens, antibiotic, antimicrobial peptide, siderophore, yeast