Vibrio parahaemolyticus was isolated from crab meat homogenate and inoculated into broth to test the effects of various media components on its growth. The bacterium grew best in a defined medium with malic acid and methionine and in another medium with lactic acid and methionine. Control samples devoid of amino acids gave very poor growth. Carbon sources were substituted in the defined medium in place of sucrose and among all tested carbon compounds, sucrose, glucose, glycerol, fructose, and mannitol caused the production of best bacterial growth. Presence of soluble starch and cellobiose in the media resulted in the production of very low biomasses of 0.18 and 0.16 OD600 respectively. When different sucrose concentrations were each tested, it was shown that sucrose concentrations of 40 and 35 mg/ml caused growth repression whereas concentrations of 15 and 20 mg/ml resulted in the best growth. Complete medium with peptone had much better increases in bacterial growth than media without peptone. Vibrio parahaemolyticus grew best at pH 7.0 and 8.0 but had the least growth at pH 11.0. Acidic pH of 3.0 was also lethal to growth. Growth inhibition occurred at NaCl concentrations of 1 and 10% while best growth of this organism occurred at NaCl concentrations of 3 and 4% at which bacterial biomass reached an OD600 of 0.81 and 0.74 respectively.
Key words: Vibrio parahaemolyticus, crab meat homogenate, organic acids, amino acids, carbon sources, peptone, pH, NaCl concentration.
