This report reviews significant developments in applications of biological catalysis in synthetic organic chemistry for the year 2007. The use of hydrolase enzymes continues to dominate the field of biotransformations, with an increasing emphasis on the application of lipases in dynamic kinetic resolutions, including processes for the deracemisation of amines and primary alcohols. There have been important developments in the use of redox-self-sufficient fusion proteins for hydroxylation reactions, and enzymatic Baeyer-Villiger reactions continue to attract attention owing to the availability of new genes. There has been renewed interest in reductases, notably enoate reductases that catalyse the asymmetric reduction of the carbon–carbon double bond in cycloalkenones and nitroalkenes. In the area of carbohydrate-transforming enzymes, there have been novel catalysts and substrates reported for glycosynthase technology and developments in both the synthesis and in situ recycling of activated nucleotide sugars for glycosyltransferases.