Isolation of Nitrate and Phosphate Removing Bacteria from Various Environmental Sites

Problem statement: Nitrate and phosphate are two major pollutants due to anthropogenic activity like excessive use of fertilizers in agriculture. Their contamination has emerged as a global problem and its potential threat is marked on the environmental sustainance as well as on the public health. Approach: The objective of the current study is to isolate efficient nitrate and phosphate removing microbes from various environmental sites that have been selected on the basis of the nature of polutants received by them and their water quality assessment. These well characterized isolates could in future be used for the remediation of waste water. 30 different sites were screened using culture based method. The nitrate and phosphate removing abilities of the microbes were checked in enriched medium (Himedia M439) after 16 h of incubation at 37°C. Results: 7 efficient isolates were obtained from rhizosphere of Water lily, Marine beaches, Paddy field and Raw sewage canal. The highest nitrate removal (88.3%) was shown by isolate (WBUNB009) from raw sewage canal and the highest phosphate removal (82.9%) was shown by isolate (WBUNB004) from rhizosphere of Water lily. Morphologically all the isolates were gram positive bacilli as reconfirmed by environmental scanning electron microscopy. Biochemically as well as physiologically they differ from each other. Conclusion/Recommendation: This study leads to the isolation of efficient nitrate and phosphate removers from environmental origin. The phosphate removing efficiency is much higher than the type strain under identical condition. These native microbes might be responsible for maintaining the phosphate and nitrate levels at the 30 sites investigated inspite of the received pollution load. These isolates could be the potential bioremedial agents for other sites with high nitrate and phosphate contamination level.