Biological control of Vibrio alginolyticus in Skeletonema costatum (Bacillariophyceae) cultures

A bacterial strain (SK-05), selected for its active growth in organic-poor substrates and inoculated in a Skeletonema costatum culture in late exponential growth, prevented the establishment of Vibrio alginolyticus, purposely introduced into the diatom culture. Since SK-05 has no bacteriostatic or antibiotic activity against V. alginolyticus, it is concluded that it has an effect of competitive exclusion, due to its ability to utilize the exudates of S. costatum, which maintain within the culture an organic-poor environment, unsuitable for Vibrio growth. It is speculated that the use of SK-05 or other strains with similar properties in commercial hatcheries, might be a viable alternative to the use of other, more expensive probiotic bacteria. (C) 1998 Elsevier Science B.V. All rights reserved.