Growth of Vibrio alginolyticus: Interacting effects on pH, temperature, salt concentration, and incubation time

The growth of five strains of Vibrio alginolyticus, using standard inoculum cells in the late logarithmic growth phase, was tested in Trypticase-Soy-broth with 0.5, 3, and 6% sodium chloride concentration (0.5, 3, 6 TSB) adjusted at pH values ranging from 4.5 to 12 in 0.5 unit. The individual growth as well as the mean growth levels for the five strains were recorded after 2, 4, 7, and 14 days incubated at 5, 10, 20, 37, and 42 °C, respectively.

V. alginolyticus strains showed most favourable growth rate in a 3% NaCl solution, while the growth in a 6% solution was lower and the lowest growth was found in the 0.5% solution. Testing the influence of low temperature the strains showed that at 10 °C and 5 °C, respectively four days and seven days elapsed before signs of growth appeared, while high temperature (42 °C) produced regular growth (except with 0.5 TSB). Under favourable temperature and salt concentration V. alginolyticus showed acceptable growth at pH values ranging from 4.5–5 to 10.5–11. After two weeks incubation at 5 °C growth could be registered. The marine strain gave sharp and accurate results in contrast to the international type cultures.