Nitrate reduction by denitrifying Bacillus Cohnii isolated from sewage treatment plant

Abstract

In this study, six bacterial colonies were isolated from the wastewater at Tiruchirappalli Corporation Sewage Treatment Plant, Panjappur, Tamil Nadu. Among the six bacterial isolates, only one has the capability to remove 90.6 % of nitrate within 120 h. The phenotypic and genotypic characteristics were identified using biochemical tests and 16S rRNA analysis. In the phylogenetic tree, the organism has 97 % similarity with Bacillus cohnii and the organism was confirmed as B. cohnii. Environmental factors such as pH, temperature, NaCl and incubation time showed the maximum nitrate reduction at pH 10, 45 °C, 5 % and 120 h, respectively. When compared with the control (without nitrate), the denitrifying bacteria expressed considerable amount protein on 57, 48, 43, 36, 33, 25, 18, 16, 14 and 12 kDa, this was probably attributed due to a higher degree of functional diversity among the bacteria.