Application of Nitrifying and Denitrifying Bacterial Consortium for Nitrogenous Waste Removal from Shrimp Culture Pond for Sustainable Cultivation

Abstract

High protein feed (38%–42%) is regularly used in shrimp culture ponds. Uneaten feed and dead plankton accumulate in nitrogenous waste in aquaculture ecosystems which are further converted into high ammonium-N, nitrate-N, and nitrite-N. Several conventional approaches have been adopted for the removal of these wastes in aquaculture ponds and hatcheries with varying degrees of success but they face critical problems such as membrane fouling, high costs, or the generation of toxic by-products. This study is based on consortium technology using nitrifying and denitrifying bacteria. Heterotrophic nitrifying Bacillus cereus PB45 and aerobic denitrifying B. cereus PB88 are mixed in equal volumes and, designated as a consortium and applied at different salinity ranges in commercial shrimp culture ponds. The results indicate that the consortium showed potential in low, medium, and high salinities. The consortium not only reduced nitrogenous waste but maintained other water quality parameters such as pH, alkalinity, hardness, and total dissolved solids (TDS). The consortium also helped to increase the average body weight (ABW) gain for shrimp. A 2 L/ha (cell density 108 cfu/mL) dose of the consortium was the optimum for medium and high salinity water and 3 L/ha (cell density 108 cfu/mL) was the best for low salinity water.