کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
3348 | 165 | 2013 | 7 صفحه PDF | دانلود رایگان |
Fermentations were performed in an external recycle bioreactor using CO2 and d-glucose at feed concentrations of 20 and 40 g L−1. Severe biofilm formation prevented kinetic analysis of suspended cell (‘chemostat’) fermentation, while perlite packing enhanced the volumetric productivity by increasing the amount of immobilised cells. The highest productivity of 6.35 g L−1 h−1 was achieved at a dilution rate of 0.56 h−1. A constant succinic acid yield of 0.69 ± 0.02 g/(g of glucose consumed) was obtained and found to be independent of the dilution rate, transient state and extent of biofilm build-up – approximately 56% of the carbon that formed phosphoenolpyruvate ended up as succinate. Byproduct analysis indicated that pyruvate oxidation proceeded solely via the formate-lyase pathway. Cell growth and corresponding biofilm formation were rapid at dilution rates higher than 0.35 h−1 when the product concentrations were low (succinic acid < 10 g L−1), while minimal growth was observed at succinic acid concentrations above this threshold.
Journal: Biochemical Engineering Journal - Volume 73, 15 April 2013, Pages 5–11