Bacterial inoculum development for effluents treatment of shrimp farming industry

In shrimp-pond farming, effective water quality management is critical for shrimp growth and survival as well as to reduce the impact of shrimp farming on the environment. Therefore, this study was conducted with the objective of developing indigenous bacterial formulation, which can effectively treat shrimp pond effluents thus improving the water quality in shrimp farming. To ascertain possible bacterial species to be used in the formulation, water samples were collected from two shrimp farms in Muara Tebas and Santubong, Kuching, Sarawak, Malaysia. Eleven water samples were collected from these two shrimp farms. Microorganisms in the water samples with the necessary characteristics such as active proteolytic, cellulolytic and amylolytic were isolated. These eight species of microorganisms were then identified based on biochemical test, API 20NE and API 20E kit, followed by Polymerase Chain Reaction (PCR) technique. The main species that had been identified as potential degraders of pond effluents belonged to the Bacillus sp.. From the primary screening on solid media, eight active isolates were chosen based on the size of the diameter of the clear zone surrounding the colonies in the plate-screening medium. A time course study was performed for 72 hours for each of the potential isolates in liquid media to analyze their growth curve and enzymes production with respect to time. These isolates were individually further grown in shaked flask cultures to determine the pattern of enzyme production, protein content and bacterial growth. All of the monocultures (eight isolates) were then combined in minimal media for 24 hours at 37oC to determine the pattern of growth and enzymes production when in combination of 1 : 1, 1 : 2, 2 : 1, 1 : 3, 3 : 1, 3 : 2 and 2 : 3. From the results obtained from biculture combination, the best combination of bacteria was then tested for their ability to grow and respond in a triculture system. 1% of Bacillus megaterium (S120): Bacillus cereus strain 3 (S65): Enterococcus casseliflavus (S11) was selected as the best triculture combination because they produced the highest enzymes of cellulase, amylase and protease. Therefore, the formulation consists of three bacterial species identified as Bacillus megaterium, Bacillus cereus and Enterococcus casseliflavus. The bacterial formulation was then tested on shrimp pond water from two different aquaculture farms and UNIMAS’s pond water. Chemical and biological parameters in the water were analyzed for seven days except for UNIMAS pond where the treatment was extended to fourteen days. There were no significant differences (P > 0.05) in water quality parameters such as orthophosphate, total phosphorus, bacterial count, temperature and pH for samples from the shrimp pond water. However, ammonia-nitrogen, nitrite, nitrate, turbidity, suspended solid, chemical oxygen demand (COD), sulfide and biochemical oxygen demand (BOD) differed significantly (P 0.05). Other parameters such as ammonia-nitrogen, nitrite, orthophosphate, total phosphorus, turbidity, suspended solid, chemical oxygen demand (COD), sulfide and biochemical oxygen demand (BOD) differed significantly (P < 0.05) compared to control experiment. The ability to reduce more than 50% of eight water quality parameters in this study clearly showed that the indigenous bacterial inoculums were a good shrimp pond effluents degrader