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Batch and continuous cultures of a newly isolated Clostridium butyricum strain were carried out on industrial glycerol, the major by-product of the bio-diesel production process. For both types of cultures, the conversion yield obtained was around 0.55 g of 1,3-propanediol formed per 1 g of glycerol consumed whereas the highest 1,3-propanediol(More)
The use of date juice as a substrate for lactic acid production was investigated. Various nitrogen sources were compared with yeast extract for efficient lactic acid production by Lactobacillus casei subsp. rhamnosus. Among different nitrogen sources added to date juice (yeast extract, ammonium sulfate, tryptic soy, urea, peptone, and casein hydrolysate),(More)
A stable continuous culture of Clostridium acetobutylicum on a complex medium containing 40 g/l glucose has been maintained for two months. At an optimal dilution rate fo 0.06 h−1, the fermentation yields 13 g/l acetone-butanol-ethanol, which corresponds to a maximal productivity of 0.75 g/l.h solvents. Due to the toxic effect of butanol, the longevity of(More)
To increase the productivity of the acetone-butanol fermentation, a hollow-fiber ultrafilter is used to separate and recycle cells in a continuous fermentation ofClostridium acetobutylicum. Under partial cell recycling and at a dilution rate of 0.5 hr−1, a cellular concentration of 20 g/l and a solvent productivity of 6.5 g/l.hr is maintained for several(More)
A systematic approach for the on-line estimation of the non measured component concentrations and the reaction rates inside chemical and biochemical reactors is presented. Two appealing features of the presented approach are worth to be mentioned. Firstly, the estimators of the reaction rates are easy to implement and in particular to calibrate. Secondly,(More)
Photophysical techniques have potential for the development of optical sensors in monitoring and controlling fermentors. In the particular case of acetone-butanol-ethanol (ABE) fermentation, carried out by bacteria of the speciesClostridium acetobutylicum, we have developed two studies based on fluorescence spectroscopy. First, we measured the intrinsic(More)
Today, intensification of anaerobic digestion is still a scientific and technical challenge. The present study proposed combined experimental and computational fluid dynamics simulations to characterize the impact of shear stress and impeller design on the biogas production after sequential additions of substrate. Liquid phase (cattle manure digestate)(More)
The fermentative properties of thermo-sensitive strain Corynebacterium glutamicum 2262 were investigated in processes coupling aerobic cell growth and the anaerobic fermentation phase. In particular, the influence of two modes of fermentation on the production of lactate, the fermentation product model, was studied. In both processes, lactate was produced(More)
The stability of continuous fermentations of Clostridium acetobutylicum can be limited by cell flocculation under conditions of high solvent production. The addition of chloride salts to a synthetic medium prevents the flocculation of the bacteria, and thus results in stable continuous cultures.