A Novel Nitrobacteria-based Microbial Sensor for Water Detection

Abstract

This paper described the development and application of a nitrifying bacteria sensor to monitor water toxicity. Four strains of bacteria with high efficiency nitrification, designated as F1, F4, Y2 and Z1, were isolated from fish pond sediment, and identified as Rhodococcus sp. (F1 and F4), Pseudomonas sp. (Y2) and Micrococcus sp. (Z1). The four bacterial strains were tested for their nitrifying capabilities. The results showed that the nitrifying rate of F1, F4, Y2 and Z1 reached 3.51, 3.43, 3.46, 3.52 mg/L·d respectively. The four strains were further cultivated for 21 days to investigate the effects of temperature, pH and inoculation amount on their NH4 +-N degradation ability. The cultivation showed that the four strains possessed optimal NH4 +-N degradation rate when temperature was 35?, pH value was 8.5, and inoculation amount was 30%. Furthermore, the carrier optimization test demonstrated that the nitrobacteria film prepared using 16% PVA, 1.2% SA, 2% NaNO3 and 75% CaCl2 had the best performance of toxicity detection. These results suggested that the nitrobacteria biosensor designed in this study was sensible and suitable for detecting water toxicity.