Bacteria, yeast and microalgae can act as producers or catalysts for the production of food ingredients, enzymes and nutraceuticals. With the current trend towards natural ingredients, there is renewed interest in microbial flavors and colors and bioprocessing using enzymes. Microbial production of substances such as organic acids and hydrocolloids also remains important. Part one describes the use of bioprocessing to make food ingredients and the applicaiton of modern techniques such systems biology, metabolic engineering, and synthetic biology. Part two discusses the use of microorganisms for the manufacture of food flavors, carotenoids, flavanoids, terpenoids, enzymes, organic acids, probiotics, bacteriocins, amino acids, biopolymers, nutraceuticals, oligosaccharides, polyunsaturated fatty acids, and vitamins.