LIN Jing , ZHENG Wei,

TIAN Yun, WANG Guizhong, ZHENG Tianling.J. Ocean Univ. China, 2013. 12 (3):

385-391

Harmful algal blooms (HABs) have led to

extensive ecological and environmental issues and huge economic losses. Various

HAB control techniques have been developed, and biological methods have been

paid more attention. Algicidal bacteria is a general designation for bacteria

which inhibit algal growth in a direct or indirect manner, and kill or damage

the algal cells. A metabolite which is strongly toxic to the dinoflagellateAlexandrium tamarensewas produced by

strain DH46 of the algalysing bacterium Alteromonas sp. The culture conditions

were optimized using a single-factor test method. Factors including carbon

source, nitrogen source, temperature, initial pH value, rotational speed and

salinity

were studied. The results showed that the cultivation of the bacteria

at 28℃and 180 r min^-1with

initial pH 7 and 30 salt contcentration favored both the cell growth and the

lysing effect of strain DH46. The optimal medium composition for strain DH46

was determined by means of uniform design experimentation, and the most

important components influencing the cell density were tryptone, yeast extract,

soluble starch, NaNO₃and MgSO₄. When the following

culture medium was used (tryptone 14.0g, yeast extract 1.63g, soluble starch

5.0g, NaNO₃1.6g, MgSO₄2.3g in 1L) , the largest bacterial dry weight (7.36gL^-1)

was obtained, which was an enhancement of 107% compared to the initial medium;

and the algal lysis rate was as high as 98.4% which increased nearly 10% after

optimization.

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