Fungi and the Development of Microbiological Chemistry 17 with secondary metabolite biosynthesis were isolated.Once the acetate labelling patterns of polyketide metabolites were established in the 1970s the emphasis of biosynthetic studies moved towards the study of the polyketide synthases.The ideas built upon knowledge gained from the fatty acid synthases.Although studies on 6-methylsalicylic acid synthase and lovastatin polyketide synthase have been reported,the main thrust of the work since the late 1980s has been with erythro synthase obtained fron cete,Sac n with a fu The pter on polyketides interesting fa cet of this work s th th enzyme s are clustere ussed later.The chemical enzymology o some fungal terpene synthases,including some of the sesquiterpene and gib berellin systems,has also been examined with results that are discussed in the relevant chapters. with secondary metabolite biosynthesis were isolated. Once the acetate labelling patterns of polyketide metabolites were established in the 1970s the emphasis of biosynthetic studies moved towards the study of the polyketide synthases. The ideas built upon knowledge gained from the fatty acid synthases. Although studies on 6-methylsalicylic acid synthase and lovastatin polyketide synthase have been reported, the main thrust of the work since the late 1980s has been with erythromycin polyketide synthase obtained from a Streptomycete, Sac￾charopolyspora erythraceae, rather than with a fungus. The results of this work are discussed in the Chapter 4 on polyketides. An interesting facet of this work is that the genes that determine the structure of these enzymes are clustered together. The significance of this is discussed later. The chemical enzymology of some fungal terpene synthases, including some of the sesquiterpene and gib￾berellin systems, has also been examined with results that are discussed in the relevant chapters. Fungi and the Development of Microbiological Chemistry 17