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Lipases (triacylglycerol acylhydrolases, EC 3.1.1.3) catalyze the hydrolysis and the synthesis of esters formed from glycerol and long-chain fatty acids. Lipases occur widely in nature, but only microbial lipases are commercially significant. The many applications of lipases include speciality organic syntheses, hydrolysis of fats and oils, modification of fats, flavor enhancement in food processing, resolution of racemic mixtures, and chemical analyses. This article discusses the production, recovery, and use of microbial lipases. Issues of enzyme kinetics, thermostability, and bioactivity are addressed. Production of recombinant lipases is detailed. Immobilized preparations of lipases are discussed. In view of the increasing understanding of lipases and their many applications in high-value syntheses and as bulk enzymes, these enzymes are having an increasing impact on bioprocessing. D

Botryococcus braunii, a green colonial microalga, is an unusually rich renewable source of hydrocarbons and other chemicals. Hydrocarbons can constitute up to 75% of the dry mass of B. braunii. This review details the various facets of biotechnology of B. braunii, including its microbiology and physiology; production of hydrocarbons and other compounds by the alga; methods of culture; downstream recovery and processing of algal hydrocarbons; and cloning of the algal genes into other microorganisms. B. braunii converts simple inorganic compounds and sunlight to potential hydrocarbon fuels and feedstocks for the chemical industry. Microorganisms such as B. braunii can, in the long run, reduce our dependence on fossil fuels and because of this B. braunii continues to attract much attention.

Cyanobacteria (blue-green algae) are photosynthetic prokaryotes used as food by humans. They have also been recognized as an excellent source of vitamins and proteins and as such are found in health food stores throughout the world. They are also reported to be a source of fine chemicals, renewable fuel and bioactive compounds. This potential is being realized as data from research in the areas of the physiology and chemistry of these organisms are gathered and the knowledge of cyanobacterial genetics and genetic engineering increased. Their role as antiviral, anti-tumour, antibacterial, anti-HIV and a food additive have been well established. The production of cyanobacteria in artificial and natural environments has been fully exploited. In this review the use of cyanobacteria and microalgae, production processes and biosynthesis of pigments, colorants and certain bioactive compounds are discussed in detail. The genetic manipulation of cyanobacteria and microalgae to improve their quality are also described at length.

Nitrile-converting enzymes are becoming commonplace in the synthesis of pharmaceuticals and commodity chemicals. These versatile biocatalysts have potential applications in different fields including synthetic biocatalysis and bioremediation. This review attempts to describe in detail the three major classes of nitrile-converting enzymes, namely nitrilases, nitrile hydratases and amidases. Various aspects of these enzymes including their occurrence, mechanism of action, characteristics and applicability in different sectors have been elaborately elucidated. Cloning of genes related to nitrile-converting enzymes is also discussed.