1.Environmental monitoring for perchlorate (rocket fuel) contamination
Perchlorate (ClO4-) is an emerging environmental contaminant, known to interfere with the functioning of human thyroid gland leading to hypothyroidism. Infants and pregnant women are the most vulnerable group to this chemical. Perchlorate is mainly used (as ammonium salt) in rockets, missiles, explosives, match box industries etc.
As per US Environmental Protection Agency (US EPA) existing guideline, perchlorate concentration at 15 ppb (microgram per litre) in drinking water is NOT expected to cause any adverse health effects. WHO consider dietary exposure of perchlorate concentration above 0.1 microgram/kg body weight/day (mean value) is of health concern.
The ongoing research at Environmental technology group in NIST mainly focuses on assessing the level of perchlorate in water and consumer products in Kerala and to find out relations (if any) on increased incidence of hypothyroidism where high contamination of perchlorate was observed. Furthermore, the study also envisages developing an environment friendly and economic bioremediation approach to decontaminate the toxic pollutant.
1. Perchlorate concentration several thousand magnitudes higher than International guidelines were found in ground water samples from few locations in Kerala.Severe contamination (up to 45,000 ppb) was found in ground water samples around the ammonium perchlorate manufacturing unit in Keezhmad in Aluwa (Ernakulam district, Kerala). Ground water contamination was observed in Keezhmad and nearby Edathala Panchayat. Continuous surveillance of ground water for perchlorate contamination was done in this area. We have screened around 200 wells in the area and based on our suggestion, as immediate solution for the problem alternate drinking water was supplied to the contaminated area by the local self government.
2. Perchlorate contamination of ground water was also observed near Thumba area (Trivamdrum district, Kerala). The recent analysis in 2014 revealed maximum contamination up to 700 ppb in well water samples.
3. Our recent analysis of ground water from Sivakasi (cracker industry area) has shown severe contamination of perchlorate up to 4500 ppb in well water samples.
2. Microbial bioprocess for perchlorate decontamination
Perchlorate is a highly persistent contaminant in the environment usual physic-chemical pollutant removal methods like adsorption or chemical reduction are not techno-economicaly feasible. But biological methods employing perchlorate reducing bacteria are very successful.
At NIIST we have developed a microbial system capable of reducing perchlorate completely into non-toxic chloride and oxygen. Lab scale studies have completed using synthetic and real effluent from industries. Real effluents from local ammonium perchlorate consuming and manufacturing units (ISRO-VSSC) were treated in the lab using the microbial system.
Several bacteria capable of reducing perchlorate was isolated in pure and molecular characterization of the novel cultures was done and nearly 30 gene sequences were submitted to GenBank.
1. Few novel strains (Serratia marcescens sp NIIST, Halomonas sp. NIIST, Bacillus Sp. NIIST) was found tolerating high salt and extreme pH and able to reduce perchlorate and nitrate simultaneously. There cultures may find application for remediation discharge brines containing high salt and perchlorate.
2. Phytoremediation of perchlorate using free floating macrophytes from local environments gave promising results.
3. Development of low cost materials for adsorptive removal of traces of perchlorate from bulk water is another activity in progress. Organic functionalization of locally available clay revealed promising results for removing perchlorate from water.
Anupama V. N., Prajeesh P.V.G., Anju S., Priya P. & Krishnakumar B (2015) Diversity of bacteria, archaea and protozoa in a perchlorate treating bioreactor. Microbiol. Res. 177, 8-14.
Sankar S, Prajeesh PVG, Anupama VN, Krishnakumar B, Hareesh, Balagopal NN, Warrier KG, Hareesh US (2014) Bifunctional Lanthanum Phosphate Substrates as Novel Adsorbents and Bio Catalyst Supports for Perchlorate Removal. DOI: 10.1016/j.jhazmat.2014.04.046
Anupama V.N., Prajeesh P.V.G. & Krishnakumar B. (2013) Perchlorate reduction by an isolated Serratia marcescens strain under high salt and extreme pH. FEMS Letters. 339, 2, 117–121.
Prajeesh P.V.G., Soumya B & Krishnakumar B. (2013) Phytoremediation of an endocrine disrupting chemical using free floating macrophytes. 25th Kerala Science Congress, Jan 29-31, Trivandrum (Best paper award under Environmental Science category).
Anupama V.N., Prajesh P.V.G., Athira V. & Krishnakumar B. (2013) Kinetics of chlorite dismutase in a perchlorate degrading reactor sludge. Environmental technology
V. N. Anupama, K. Kannan, P. V. G. Prajeesh, S. Rugmini, and B. Krishnakumar. (2012) Perchlorate, chlorate and bromate in water samples from the South-West coast of India. Water Science & Technology-Water supply, 12.5, 595-603.
V.N, Anupama, Rugminisukumar and Krishnakumar B (2010) Perchlorate contamination of water sources in kerala and a biological approach to detoxify the pollutant. Kerala Science Congress. Thiruvananthapuram (Best paper award).
1. INDEPTH – Under 12 Five year plan project (2012-2017): Under this project through screening of ground water samples from different places in India will be done for perchlorate monitoring. Particular attention will be paid at places where perchlorate is handled in bulk.
2. Scale up studies and field level testing and implementation of perchlorate remediation process is also targeted in this study.
3.Microbial bioactive compounds
Bioactive molecules from microorganisms find application in many industrial sectors. Violacein is purple blue pigmented compound reported to have antimicrobial, antipxidant, cytotoxic and anticancer properties etc.
The ongoing study at NIIST produces high levels of violacein using an isolated Chromobacterium sp. The fermentation conditions and downstream steps for purification were optimized. The crystalline violacein produced was found have strong anti-bacterial, antifungal and anticancer properties.
The pure violacein produced was subjected to derivatization (semi-synthesis) for novel compounds for potential applications.
Process for the production of Violacein and its derivatives deoxyviolacein containing bioactive pigment from Chromobacterium sp. (MTCC 5522).
4.Environmental impact of emerging micro-pollutants:
Nano materials are increasingly being used in large number of consumer products. However, at least part of these materials ultimately reaches the natural environment mainly during waste disposal. In the natural environment how these synthetic materials affecting the various life forms, especially the microorganisms like Bacteria, Archaea, protozoa, micro-metazoa are the focus of research.
One of the specific researches is on quorum sensing inhibition by synthetic nano materials inorganic (Au, Ag, ZnO, CdTe Quantum Dot, etc.) and organic (Fullerene, Graphene, etc.) synthetic nano materials.
Quorum sensing inhibition by synthetic organic nano materials
5. Higher trophic organisms in anaerobic environments:
In addition to Bacteria and Archaea, anaerobic environments including wastetreating bioreactors and natural environments, higher trophic organisms like protozoa and micro-metazoa (micro-animals) also inhabit these habitats. The ecological niches occupied by these organisms have functional importance in the overall functioning of the reactor. Many anaerobic protozoa inhabit waste treating bioreactor and plays significant role such as intracellular digestion of complex organics, nutrient recycling and biomass reduction through grazing activity and harbour endo-symbiotic methanogens. The ongoing research focuses on the diversity and population dynamics of higher trophic organisms and to analyze their functional importance in waste treatment.