한국환경과학회지 제17권 제4호 (p.439-449)

적조생물 Cochlodinium polykrikoides를 저해하는 Micrococcus luteus SY-13이 생산하는 살조물질의 특성과 해양생물에 미치는 영향

Characteristics of Algicide Produced by Micrococcus luteusSY-13 Inhibiting Cochlodinium polykrikoides and the Effects on Marine Organisms
키워드 :
Algicidal activity,Algicidal bacterium,Cochlodinium polykrikoides,Micrococcus luteus SY-13,Harmful algal blooms,Red tide

초록

Algicidal bacterium was isolated from sea water during the declining period of Cochlodinium polykrikoides blooms and this bacterium had a significant algicidal activity against C. polykrikoides. In this study, algicidal bacterium was identified on the basis of biochemical and chemotaxonomic characteristics, and analysis of 16S rDNA sequences. The algicidal bacterium showed 98.6% homology with Micrococcus luteus ATCC 381T. Therefore, this bacterium was designated Micrococcus luteus SY-13. The optimal culture conditions of the algicidal bacterium was 25℃, initial pH 8.0, and 3.0% NaCl concentration. M. luteus SY-13 is assumed to produce secondary metabolites which have algicidal activity. When 10% culture filtrate of this strain was applied to C. polykrikoides (1.0 × 104 cells/㎖) cultures, over 98% of C. polykrikoides cells were destroyed within 6 hours. The culture filtrate of M. luteus SY-13 exhibited similar algicidal activity after heat-treatment at 121℃ for 15 min. While algicidal activity remained in filtrates with pH adjusted to 8.0, loss of algicidal activity occurred when the pHs of filtrates were adjusted to over 9.0 or heat-treated at 121∼180℃ for 1 hour. M. luteus SY-13 showed significant algicidal activities against C. polykrikoides (98.9%) and a wide algicidal range against various harmful algal bloom (HAB) species. However, there was no algicidal effect on diatom and marine livefood organisms except Isocrysis galbana. These results suggest that M. luteus SY-13 could be a candidate for use in the control of HABs.