Author:DING Yu, JIAN Ji—Chang, WU Zao—He,. BAILi—Li, LIU Jian—Feng, LIN Dan, YU Jun

(Guangdong Provincial Key Lab of Pathogenic Biology and Epidemiology for Aquatic Economic Animals; Fisheries College。Guangdong Ocean University，Zhanjiang，524025)

Key words:Huguangyan Maar Lake， Microorganism， Antagonistic bacterium， Cultural condition， Screening

Abstract:

Samples of bacterium taken from Huguangyan Maar Lake are isolated and purified using spread plate method and streak plate technique．The partial characteristics is analyzed morphologically and physiologically．The heterotrophic bacteria，fungi，and vibrio are assessed in plate colony—counting method．Antagonistic bacteria to vibrio are screened and their antagonistic ability studied using cup method．The results show a prominent difference in the quantity and species of microorganisms in different sites．The total numbers of heterotrophic bacteria and fungi are(1.3— 8.6)×108 and (0.1— 5.7)×107cfu/g in sediment，while (0.5— 6.7)x105 and (0.4— 1.1)x103 cfu／ml in water，respectively．It was found that 16 bacteria strains，which account for 10.8％ of the total (148)，are obviously inhibitive to Vibrio alginolyticus，and bacteria DH078 and DH113 have a significant inhibitive zone．The results also show that antibiotic activity of DH078 is the strongest after being cultured for four days in nutrient broth medium．The optimal cultural conditions for their antibiotic ability are：broth medium of 2-time dilution，0.6％ peptone，0.2％ yeast extract，0.6％ beef extract，0 salinity，and pH 7.0．It is Obvious that the microorganism resources in Huguangyan Maar Lake are quite abundant and valuable．The scientific foundation for protection and sufficient utilization of these microorganism resources are also provided in this paper.

湖光岩拮抗菌的研究