Biopotentiality of High Efficient Aerobic Denitrifier Bacillus megaterium S379 for Intensive Aquaculture Water Quality Management

Abstract

Excessive nitrite accumulation is a very tough issue for intensive aquaculture. A high efficient aerobic denitrifier Bacillus megaterium S379 with 91.71±0.17% of NO2--N (65 mg L-1) removal was successfully isolated for solving the problem. Denitrification of S379 showed excellent environment adaptation that it kept high nitrite removal ratio (more than 85%) when temperature ranged from 25°C to 40°C and pH varied between 7.0 and 9.0, and could endure as high as 560 mg L-1 of NO2--N. Immobilization of S379 could enhance denitrification even when NO2--N adding amount got to 340 mg L-1. Immobilized cells also showed well pollutants removal performance in aquaculture wastewater treatment. Moreover, S379 possessed positive hydrolase activities for starch, casein, cellulose and fat and bore more than 60 ppt of salinity. Totally, all the results revealed significant potentiality of immobilized S379 applied in aquaculture water quality management.