Isolation and characterization of potential probiotic bacteria suitable for mollusk larvae cultures

Abstract

Guts of Crassostrea gigas, C. corteziensis, and Atrina maura were screened for bacilli and lactic acid bacteria with probiotic properties for bivalve mollusks. Characterization of the isolates included Gram stain, morphology, cell arrangement, catalase and hemolytic activity, hydrophobicity, autoaggregation, coaggregation against Vibrio sinaloensis VHPC23, biofilm formation, counting of colony forming units (CFU), NaCl and pH tolerance, enzymatic activity, resistance to antibiotics, antagonism against Vibrio sinaloensis VHPC23, and molecular identification. Three isolates (BCR 4-3, BALCR 5-2, and BALOR 2-3) showed no hemolytic activity, high tolerance to pH and salinity, high adhesion potential, high autoaggregation and coaggregation, biofilm formation, well growth, and some resistance to antibiotics. The isolates were identified as Bacillus licheniformis (BCR 4-3) and Leuconostoc mesenteroides (BALCR 5-2 and BALOR 2-3). The strains showed basic characteristics to be used as probiotics in mollusk larvae cultures.