Enzymatic activity of vibrios isolated from the hemolymph of cultured Litopenaeus vannamei shrimp

The enzymatic characterization of 100 strains of Vibrio isolated from the hemolymph of Litopenaeus vannamei was performed. All the strains were subjected to caseinase (Cas), gelatinase (Gel), elastase (Elas), phospholipase (Phos), lipase (Lip) and beta-hemolysis detection. The enzymatic profile indicated the following positivity indices: 96 % of the isolates were Cas(+), 80 % Gel(+), 35 % Elas(+), 94 % Phos(+), 58 % Lip(+), and 38 % expressed the ability to produce beta-hemolysis in sheep erythrocytes. Coincidental exoenzymatic expression was observed in 99 % of the isolates, and the profiles GelCasPhos (16 %) and GelCasPhosLip (16 %) were the most frequent. Additional enzymatic activity experiments in 24 strains showed a positivity index higher than 90 % for esterase (C4), leucine arylamidase, acid phosphatase and alkaline phosphatase.