This handbook offers practical guidance for fundamental experiments in environmental biotechnology, industrial biotechnology, and plant biotechnology, encompassing crucial aspects such as the isolation of industrially significant microorganisms, screening for amylase producers, yeast immobilization, BOD and COD assessments, microbial cellulose degradation, and ethanol production using various substrates, the handbook comprehensively records all methodologies, reagent preparation, media composition, callus initiation, micro propagation, DNA isolation, synthetic seeds, and enzyme assays. It illustrates experimental procedures and the valuable role of microorganisms and their enzymatic potential in contributing to sustainable societal and economic development. This emphasizes on the efficient utilization of microorganisms to produce a diverse range of value-added products and processes, including food, feed, enzymes, antibiotics, organic acids, mycotoxins, vaccines, drugs, ethanol, solvents, and waste disposal. The handbook uniquely focuses on cost-effective chemicals and the avoidance of advanced instruments in analytical procedures. It intricately details step-by-step processes, enabling users to independently execute experiments without external assistance. The authors express their gratitude to the Management, Secretary, Principal, Head, and all the Faculties in the Department of Biotechnology, PSG College of Arts & Science, Coimbatore-14.