Extraction of primary and secondary metabolites

Several new methods besides the usual organic solvent extraction have been developed over the last few years for the extraction of primary and secondary metabolites. These are: alcohol extraction with various biocompatible solvents, recovery of carboxylic acids and antibiotics with reactive extraction, dissociation extraction, aqueous two-phase extraction, and supercritical and near critical fluid extraction. Extraction and re-extraction processes are integrated into a single step by emulsion liquid membrane and solid supported liquid membrane extractions. These extraction processes are discussed and compared in this review, along with extraction with reversed micelles, and reactive extraction with the formation of a third phase at the organic-aqueous interface.