The production of native trypsin-like protease (TLP) in wild type strains of Fusarium oxysporum (214) and F venenatum (A3/5) was assessed and compared with the expression of recombinant glucoamylase (GAM) under the F oxysporum TLP promoter in F venenatum JeRS 325. In the two non-recombinant strains, TLP was only detected in the supernatants of batch cultures after the onset of stationary phase and TLP production was highest in the presence of a proteinaceous nitrogen source at pH 7.5. In chemostat cultures of F oxysporum, the specific TLP production rate was negatively correlated with specific growth rate (mu = 0.03-0.04 h(-1)). In F venenatum, A3/5 at dilution rates between 0.06 and 0.15 h(-1), specific TLP production was also negatively correlated with specific growth rate. The F oxysporum TLP promoter regulates GAM production in E venenatum JeRS 325, but the specific GAM production rate is known to be constant between 0.05 and 0.19 h(-1), showing that regulation of the promoter in the recombinant host differs from that in the native strain. Western blot analysis demonstrated that GAM production began in batch cultures of F venenatum JeRS 325 during the decelerating growth phase, and that de novo synthesis of GAM occurred during stationary phase. (C) 2003 Elsevier Science Inc. All rights reserved.