Production of extracellular polymeric substances (EPS) of floc-forming bacteria isolated from intensive shrimp ponds

Abstract

One of the main characteristics of floc-forming bacteria is their ability to synthesize extracellular polymeric substances (EPS). EPS is produced by floc-forming bacteria play a definite role in bioflocculation. In this present study we identified floc-forming bacteria that produce EPS. Floc samples were formed by adding organic carbon into shrimp pond’s water in Xuyen Moc, Ba Ria Vung Tau province and then used to isolate floc-associated bacteria. Among the isolated strains three (W3, W9 and W8) produce the highest EPS production (5.14 g/L, 5.17 g/L and 6.03g/L, respectively). Comparative analysis of the 16S rRNA sequence in the GenBank database and biochemical test revealed that these bacteria identified as Chryseobacterium indologenes, Pseudomonas pseudoalcaligenes strain 15 and Pseudomonas pseudoalcaligenes strain RW51, respectively. The discovery of these bacteria’s EPS production is expected to prompt further studies that eventually produce a commercial probiotics product for shrimp farming in Ba Ria Vung Tau. Key words: Biofloculation, Floc-forming bacteria, Extracellular polymeric substances, Chryseobacterium indologenes, Pseudomonas pseudoalcaligenes strain 15, Pseudomonas pseudoalcaligenes strain RW51