The field of industrial microbiology involves a thorough knowledge of the microbial physiology behind the processes in the large-scale, profit-oriented production of microbe-related goods which are the subject of the field. In recent times a paradigm shift has occurred, and a molecular understanding of the various processes by which plants, animals and microorganisms are manipulated is now central to industrial microbiology. Thus the various applications of industrial microbiology are covered broadly, with emphasis on the physiological and genomic principles behind these applications. Relevance of the new elements such as bioinformatics, genomics, proteomics, site-directed mutation and metabolic engineering, which have necessitated the paradigm shift in industrial microbiology are discussed.