Green Chemistry and Sustainable Energy

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Mangroves and euryhaline fishes employ desalination mechanisms. They can serve as models that can provide insights into developing novel, bio-inspired desalination devices.

Mangroves usually grow along water logged shorelines, absorping dissolved salt through the roots. Researchers at NERI are studying the microscopic salt glands located mainly on the leaf surfaces of some mangrove species. These glands help in maintaining the salt balance within cells by removing excess salts from the tissues in the form of secretions.

Other studies at NERI focus on the molecular and structural mechanisms of desalination in euryhaline fishes, which constantly face osmoregulatory challenges as they live in both fresh and seawater. In order to maintain their body fluid homeostasis, these fishes have developed highly versatile osmoregulatory mechanisms that can switch from removal of excess water and sequestering salt in the freshwater environment to undergoing the same process in the seawater environment.

Conventional sample preparation procedures for environmental matrices use excessive amounts of potentially toxic solvents and generate potentially toxic waste. Hence, NERI researchers are developing environmentally benign and chemically sustainable, including solventless and solvent-minimized miniaturized approaches for sample preparation. Novel materials are designed and tested as sorbents for environmental contaminants. These techniques are being developed with the view of applying them for onsite analytical applications.

Microbial fuel cells (MFCs), which convert chemical energy to electrical energy by the catalytic reaction of microorganisms, have many potential uses. The use of wastewater as a substrate for microbial action has dual benefits - water treatment and energy generation. NERI researchers are interested in MFC technology for wastewater treatment and alternative clean energy production. The research aims to understand the microbial community and identify suitable species, develop ideal electrodes, increase electronic power conversion and optimize energy management, optimize MFC design, and develop prototype MFCs for scale-up.

Plant waste is the most voluminous waste worldwide. NERI researchers are developing methods to transform plant waste to useful by-products by applying ecological selection principles from tropical peatlands. Peatlands undergo rapid oxidative degradation to release sequestered plant biomass carbon as carbon dioxide. By characterising consortia of peatland microbes and describing their natural physicochemical environment, natural bioprocesses that degrade lignocellulosic wastes may be optimised. Metabolomic studies on these consortia will help identify novel enzymes and useful metabolites produced during the degradative process.

Highlights

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Development of “Green” Sample Preparation Procedures

Various environmentally benign (“green”) miniaturized sample preparation approaches are being developed to deal with environmental aqueous contaminants, integrated automatically with analysis by gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. Researchers are also are focused on the design and evaluation of novel ‘green’ materials as sorbents for environmental contaminants. The ultimate aim is to have a fully integrative sample preparation and analytical platform that can be operated autonomously or semi-autonomously over extended periods of time that can be located onsite where water quality monitoring is needed.

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Microbial Fuel Cells – Generation of Clean Electricity

Microbial Fuel Cells (MFCs) use bacteria to convert organic waste material into electrical energy. This programme aims to use wastewater which serves as a substrate for microbial activity which in turn provides water treatment and alternative clean energy production. The team aims to understand the microbial community in wastewater and identify suitable species, develop ideal electrodes, increase power conversion and optimize energy management.

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Waste-to-Energy Conversion

Laboratory-scale experiments to determine the optimal operating conditions for the anaerobic digestion and gasification systems of various kinds of solid wastes are being conducted. The aim is to enhance existing technologies to maximize energy recovery from municipal solid waste such as food waste and horticultural waste. The key significance of this research is the sustainable production of energy from waste materials.

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Understanding of the Environmental Microbial Processes in Waste-to-Energy Conversion

Plant waste is the most voluminous waste worldwide. However, 70% of plant biomass is lignocellulose, which does not easily undergo biodegradation. The sequestered plant biomass in these ecosystems undergoes rapid oxidative degradation when peatlands are drained for agriculture and it releases the carbon as carbon dioxide into the atmosphere. In order to understand peatland dynamics, system-level technologies such as metagenomics and metabolomics, combined with custom computational platforms are being applied. Using these technologies, we have documented a database for the consortia of microbes, described their natural physicochemical environment, and developed an understanding of their metabolic processes.