Isolation, Identification, and Optimization of Culture Conditions of a Bioflocculant-Producing BacteriumBacillus megateriumSP1 and Its Application in Aquaculture Wastewater Treatment

Abstract

A bioflocculant-producing bacterium,Bacillus megateriumSP1, was isolated from biofloc in pond water and identified by using both 16S rDNA sequencing analysis and a Biolog GEN III MicroStation System. The optimal carbon and nitrogen sources forBacillus megateriumSP1 were 20 g L−1of glucose and 0.5 g L−1of beef extract at 30°C and pH 7. The bioflocculant produced by strain SP1 under optimal culture conditions was applied into aquaculture wastewater treatment. The removal rates of chemical oxygen demand (COD), total ammonia nitrogen (TAN), and suspended solids (SS) in aquaculture wastewater reached 64, 63.61, and 83.8%, respectively. The volume of biofloc (FV) increased from 4.93 to 25.97 mL L−1. The addition ofBacillus megateriumSP1 in aquaculture wastewater could effectively improve aquaculture water quality, promote the formation of biofloc, and then form an efficient and healthy aquaculture model based on biofloc technology.