ABSTRACT
This chapter is primarily concerned with providing a background to lipid biochemistry and biosynthesis as this is the common and main feature of most, but not all, surfactants. The metabolic pathways involved in the synthesis of the precursors of biosurfactants are diverse and to some extent dependent on the nature of the principal carbon source. The chapter gives an account of the main biosynthetic pathways leading to fatty acids and fatty acyl-containing lipids in microbial systems. The great bulk of reports of biosurfactant production by microorganisms relate to hydrocarbon fermentations. The initial hydroxylation of n-alkanes and subsequent dehydrogenations to produce fatty acids occurs in the microsomal fraction of the cell. Phospholipids are ubiquitous to all living organisms, where they are usually constituents of cell membranes. The acetyl-CoA pool must then be used to supply all the needs of the bacterial cell: synthesis of citrate for the Krebs cycle and other reactions as well as synthesis of fatty acids.
