کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4771 | 244 | 2007 | 8 صفحه PDF | دانلود رایگان |

The effects of post-induction nutrient feed rates, on recombinant streptokinase production in fed-batch processes, were investigated using various feed profiles. Recombinant streptokinase was produced using a secretory expression system and was induced by a temperature up-shift, using a temperature-sensitive λPL promoter. The specific growth rates decreased sharply upon induction of recombinant protein expression, thus necessitating a variable feed strategy in the post-induction phase. The various feed profiles employed in the post-induction phase included constant feed rates, linearly increasing feed rate and exponentially varying feed rates. Significant differences were obtained in the specific activity of streptokinase produced in these fed-batch processes. A maximum activity per unit biomass of 4.96 × 106 and 4.43 × 106 IU/g DCW was achieved for exponentially decreasing feed and linearly increasing feed, respectively. The decrease in specific growth rate during the post-induction phase was also less pronounced in these cases in comparison to other fed-batch experiments. It was observed that streptokinase productivity is governed by the nutrient feed rate per unit biomass at a critical juncture after induction. The highest activity per unit biomass was obtained when the nutrient feed rate per unit biomass was around 0.7–0.8 g glucose (g DCW)−1 h−1, between 2 and 4 h after induction.
Journal: Biochemical Engineering Journal - Volume 33, Issue 1, January 2007, Pages 34–41