J. M. Sablayrolles

Bio: J. M. Sablayrolles is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Butanediol. The author has an hindex of 1, co-authored 1 publications receiving 56 citations.

Butanediol production by Aerobacter aerogenes NRRL B199: Effects of initial substrate concentration and aeration agitation

Abstract: Butanediol production by Aerobacter aerogenes NRRL B199 grown on glucose requires an optimal rate of aeration for the obtention of butanediol 2, 3. In the absence of air, Aerobacter aerogenes NRRL B199 growth and production are weak. Agitation-aeration is necessary for producing the biomass, but an excess of oxygen proves to be toxic with regard to metabolite production. Oxygen is a limiting substrate with regard to growth and an inhibitor with regard to the specific metabolite productivity. This observation is discussed from a kinetic stand point and in relation to the search for the optimum oxygen transfer coefficient (KLa), which is found to be in the range of 50–100h−1. It has also been observed that KLa increases during the fermentation cycle. The initial substrate concentration effects the yield production of biomass and butanediol production. Low yields of butanediol are obtained at low initial sugar concentrations, but good yields of butanediol are obtained (0.45 g/g) at high concentrations of glucose (195 g/L). Carbon substrates and butanediol are inhibitors of cell growth while butanediol is not quite an inhibitor of the specific rate of butanediol production for the range of butanediol of 0–100 g/L.

Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates

Abstract: This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates (also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL-1 can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR), packed bed reactor (PBR), fluidized bed reactor (FBR), airlift reactor (ALR), upflow anaerobic sludge blanket (UASB) reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes.

Mechanism of enhanced oxygen transfer in fermentation using emulsified oxygen-vectors.

Abstract: Limitations of oxygen transfer in fermentation can be solved using auxiliary liquids immiscible in the aqueous phase The liquids (called oxygen-vectors) used in this study were hydrocarbon (n-dodecane) and perfluorocarbon (forane F66E) in which oxygen is highly soluble (549 mg/L in n-dodecane and 118 mg/L in forane F66E at 35 degrees C in contact with air at atmospheric pressure) It has been demonstrated that the use of n-dodecane emulsion in a culture of Aerobacter aerogenes enabled a 3 5-fold increase of the volumetric oxygen transfer coefficient(k(L)a) calculated on a per-liter aqueous phase basis The droplet size of the vector played a crucial role in the phenomena When a static contact between gas bubble and vector droplet was established in water, the vector covered the bubble, in agreement with positive values of the spreading coefficient for these fluids The determination of the oxygen transfer coefficients (k(L)) in a reactor with a definite interfacial area enabled the main resistance to be located in the boundary layer of the waterside either for a gas-water or a vector-water interface Because oxygen consumption by weakly hydrophobic cells can only occur in the aqueous phase, the oxygen transfer is achieved according to the following pathway: gas-vector-water-cell Finally, a mechanism for oxygen transfer within this four-phased system is proposed

The Microbial Production of 2,3-Butanediol

Abstract: Publisher Summary This chapter provides a comprehensive survey of diol production, including biochemistry, microbiology, and process engineering Two microbial species have demonstrated a potential for diol production on a commercial scale Klebsiella pneumoniae, with broad substrate and environmental adaptability, is the most thoroughly investigated organism The ability to utilize starchy feedstocks is the main advantage of Bacillus polymya Utilization of “waste” cellulosic substrates is generally recommended for improvement of process economics Efficient conversion of hemicellulosic carbohydrates is thus essential The optimal conditions for bioconversion of glucose are clearly distinct from those for xylose This is especially true in terms of culture pH and aeration and to a lesser extent in temperature and nutrient supplementation The most effective process designs may permit separate conditions for the consumption of these sugars In a batch operation, this could be accomplished through a midrun adjustment of key environmental parameters In continuous production, separate reactors could be operated in a series with residence times and conditions established for optimal consumption of the glucose and xylose Recovery of butanediol from fermented broths is especially difficult due to the physical and chemical properties of the compound Solvent extraction and steam stripping appear to be the most effective alternatives at present Incentives to seek renewable alternatives to petroleum-based fuels and chemicals in combination with advances in microbial process efficiency may yet result in an economically viable system for the production of butanediol from biomass resources