Energy resources 7 Renewable resources 7 Fermentation 5 Food resources 5 Forest resources 5 Land resources 5 Industrial Microbiology 4 Microbial biotechnology 4 Microbiological Techniques 4 Mineral resources 4 Nuclear pollution 4 Radiation pollution 4 Sustainable engineering 4 Wasteland reclamation 4 Water resources 4 Watershed management 4 Disaster management 3 Ecosystems 3 Environmental economics 3 Environmental engineering 3 Green chemistry 3 Human population 3 Marine pollution 3 Natural disasters 3 Natural resources 3 Non renewable resources 3 Renewable energy sources 3 Water resources development 3 Water-supply 3 physiology 3