This book is about different Enzymes from various sources that play an important role in the degradation of an array of pollutants with simultaneous generation of value-added products. This is an “Edited Book� which deals a comprehensive knowledge on the role of different microorganisms/their enzymes in the degradation of pollutants, wastewater treatment with simultaneous production of value added products. It also deals the current state, perspectives and various challenges associated with the microbial/enzymatic degradation of environmental pollutants. This book will provide a profound knowledge on the importance of microorganisms/their enzymes in the degradation of pollutants like pesticides, antibiotics, toxic/hazardous chemicals, endocrine disrupting chemicals/compounds with production of value-added products like bioplastics for the sustainable development of society. It covers various existing wastewater treatment approaches using microorganisms alone and /or in combination of other methods with their merits, demerits and future prospects.