Biopotentiality of Bacillus cereus PB45 for nitrogenous waste detoxification in ex situ model

Abstract

A bacterial strain PB45 was isolated from an intensive shrimp culture pond, and its nitrification capability was studied. On the basis of 16S ribosomal DNA (rDNA) analysis, strain PB45 was identified as Bacillus cereus PB45. PB45 has the potential to remove $$ {NH}_4^{+}-\mathrm{N} $$ , $$ {\mathrm{NO}}_3^{-}-\mathrm{N} $$ , and $$ {\mathrm{NO}}_2^{-}-\mathrm{N} $$ at the rates of 66.6, 79.4, and 50%, respectively. The optimum pH, temperature, and dissolved oxygen for the highest nitrification process of the PB45 were 8.0, 30 °C, and 6.68 mg/l (200 rpm), respectively. PB45 could express periplasmic nitrate reductase (napA), hydroxylamine oxidoreductase (hao), and nitrite reductase (nirS) which are essential to complete heterotrophic nitrification and aerobic denitrification process. Removal of $$ {NH}_4^{+}-\mathrm{N} $$ , $$ {\mathrm{NO}}_3^{-}-\mathrm{N} $$ , and $$ {\mathrm{NO}}_2^{-}-\mathrm{N} $$ in an aquarium base shrimp wastewater system was recorded to be 99.76, 99.37, and 99.72%, respectively, by PB45. This result indicated that PB45 has the prospect for future full-scale application in commercial shrimp culture.