Phân lập vi khuẩn có khả năng chuyển hóa nitrite trong một số ao nuôi tôm ở Bạc Liêu

Abstract

In the nitrogen cycle, nitrite is produced by the biological oxidation of ammonium under aerobic condition. Ammonium accumulated in aquaculture ponds due to feed leftovers and wastes is oxidized to nitrite by bacteria. Increased concentration of nitrite in ponds poses toxic effects to fish, shrimp resulting in low yield and quality. This study aimed at isolation and screen for indigenous bacteria capable of effectively transforming nitrite. Sixteen bacterial isolates were isolated from water and sediment samples collected in shrimp ponds in Bac Lieu. These isolates grew in liquid minimal salt medium supplemented with NaNO2as the only nitrogen source. The data showed that isolates BLS1.3, BLW2.2 and BLW2.4 were able to transform nitrite with higher efficiency than the others (>56.3%) after 7 days of incubation. Among the three isolates, BLW2.2 was the most potential one for the conversion of nitrite, obtaining 97.2% after 3 days of inoculation.