%A P R Patnaik %O Copyright of this article belongs to Elsevier Science. %J Process Biochemistry %T Improvement of the microbial production of streptokinase by controlled filtering of process noise %X Disturbances during operation are an ubiquitous feature of large-scale fermentations. This kind of process noise is often describable by a Gaussian distribution and is considered undesirable but unavoidable. In this paper, the fed-batch production of streptokinase (SK) was studied when such disturbances occurred in the inflow rate of the substrate. As the variance of the noise increased upto 6% of the instantaneous value of the flowrate, there was a gradual improvement in the SK activity, after which the activity decreased for larger variances. The peak activity (10?850 U/ml) was 22% higher than for a smooth noise-free feed. Similar earlier observations for ?-galactosidase and ?-lactamase suggest that normal disturbances may be harnessed to enhance fermentation efficiency by filtering them such that they are maintained within an optimal range. %N 3-4 %K Streptokinase fermentation; Inflow noise; Process improvement; Controlled filtering %P 309-315 %V 35 %D 1999 %I Elsevier Science %R doi:10.1016/S0032-9592(99)00073-4 %L open804