When Brevibacterium linens ATCC 9172 was grown in shake flasks, it produced a cell-associated lipase with a specific activity of 152 to 188 U g(-1) cells depending on the composition of the growth medium. There was no growth in media containing tributyrine as the sole carbon source. The cell-associated lipase had maximum activity at pH 8.0 and 37 degreesC and was strongly inhibited by 3,4-dichloroisocoumarin, an inhibitor specific for serine esterases. Cell-associated activity was released from the cells by treatment with lysozyme. The kinetics of lipase formation was closely related to the amount of biomass formed during growth.