Determination of nitrate utilization efficiency of selective strain of Bacillus sp. isolated from Eutrophic Lake, Theerthamkara, Kasaragod, Kerala

Nitrate pollutants increase the growth of algal bloom, resulting in fresh water eutrophication. The high nitrogen level in wastewater has become a growing concern, which has risen the necessity to develop efficient nitrogen removal techniques. Biological denitrification, which is the reduction of oxidized nitrogen compounds like nitrate or nitrite to gaseous nitrogen compounds, is the most important and widely used method to treat nitrate wastes as it enables the transformation of nitrogen compounds into harmless nitrogen gas. As such, this study collected samples from Eutrophic Lake, picking isolates of bacterial strain with good growth rates in the nitrate medium. The selected bacterial strains were cultured on media 1and 2 and by means of UV-visible spectrophotometer, the nitrate removal efficiency and growth were detected at 410 nm and 600 nm OD respectively. After comparing three bacterial strains, it was found that RN1 had a higher efficiency in nitrate removal at 1000ppm nitrate concentration. At an optimum temperature of 37°C, pH of 7, and agitation of 121 rpm, after 432 hrs of the treatment, RN1 showed an optimum growth, equal to 0.1859 OD in 1000ppm nitrate solution with dextrose. Also the spectral analysis of RN1 strain showed 85% removal efficiency, thus making this strain the best one. Confirmed and identified as Bacillus species, it can be recommended for the bioremoval process of nitrate from wastewater.