Isolation and Properties of Bacteriocin-producing Microorganisms

Bacteriocin 생산균주의 분리 및 성질

Bacteriocin-producing microorganisms were screened from raw milk and tested their antimicrobial activities against Lactobacillus plantarum ATCC 8014 as target organism, Antimicrobial substances isolated showed broad antimicrobial spectra against Gram positives and negatives. Strain 1112-1 was selected as a test organism due to its highest antimicrobial activity among the isolates. Antimicrobial substance produced by 1112-1 completely suppressed the growth of Lactobacillus plantarum at 230 IUIml and showed 11% growth inhibition of E. coli at 500 IUIrnl level. The antimicrobial substance was found to be proteinaceous material which was inactivated by carboxypeptidase, elastase, alpha amylase, amyloglucosidase, pronase, protease IV, alpha chymotrypsin, ficin, cellulase, phosphatase and lipase. The molecular weight was estimated by SDS-PAGE as 5,900. The isolate 1112-1 was identified as one of the related strains of Lactococcus sp. The strain was different from Lactococcus lactis in the following characteristics: late positive in maltose and sucrose fermentation; positive in mannitol and salicin fermentation; negative in lactose fermentation.

원유로부터 bacteriocin을 생산하는 미생물을 분리하고 이 균주들을 중심으로 Lactobacillus plantarum을 target organism으로 하여 항균력을 비교하였다. 분리된 항균성물질들은 Gram양성 및 음성균에 대하여 넓은 항균 spectrum을 보였으며 선발균주 중 최종적으로 항균력이 가장 높은 1112-1을 우량균주로 선발하였다. 선발한 1112-2 균주의 항균성물질 230 IU/ml 첨가시에 Lactobacillus plantarum의 생육은 완전히 억제되었으며 500IU/ml 첨가시 E.coli의 생육은 대조구조에 비하여 11 억제되었다.