Bacteria strain B50 was isolated from soil sample collected on seaside of the north of Vietnam and was identified as  Bacillus licheniformis according to descriptions of Bergey’s Manual of systematic Bacteriology and analysis of 16s rRna sequence. This strain well grows on media with simple strates and showed exocellular enzymatic activities, such as chitinase, amylase, protease and  CMC - ase.  Therefore, it was chosen for probiotic production to degrade quickly undesirable organic substances in order to reduce pollution of shrimp culture ponds.