Lipase activity in Streptomyces lividans, Streptomyces clavuligerus, Streptomyces coelicolor, and Streptomyces ces rimosus and a wild-type and recombinant strain of Saccharoplyspora erythraea (formerly Streptomyces erythreus) was studied. Optimization of a sensitive and accurate titration method for detection of lipase activity in each strain took place to investigate individual lipase characteristics within submerged culture containing oil as a partial carbon source. Lipases also were compared with respect to the location of the enzyme in relation to the cell. Lipase activity was not compared in terms of specificity. The results show that, in all strains studied, the lipase enzyme appears to be associated with the cell. Lipase: activity of the strains investigated, with the exception of S. clavuligerus and S. coelicolor, was produced in the absence of oil in the process media, although cell-associated lipase activity levels were elevated in the presence of increasing oil concentrations. Lipase activity in S. clavuligerus was detected only in the presence of a oil substrate, and lipase activity in S. coelicolor was detected only if oil was present at high concentration in the culture medium when compared with the other strains studied.