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31.
Jean-Marc Aldric Jean-Paul Lecomte Philippe Thonart 《Applied biochemistry and biotechnology》2009,153(1-3):67-79
A two-phase partitioning bioreactor to treat gas effluents polluted by volatile organic compound has been developed. In this work, both the mass transfer of isopropylbenzene (IPB) and oxygen have been considered in relation to their influence on the hydrodynamics of the reactor and the type of silicone oils used as a second phase. The synergistic effect of silicone oil and stirrer speed on the global oxygen mass transfer coefficient (K L a) and gas holdup (up to 12%) have been investigated. The addition of 10% of low viscosity silicone oil (10 cSt) in the reactor does not significantly affect the oxygen transfer rate. The very high solubility of IPB in the silicone oil leads to an enhancement of driving force term, especially for high fraction of silicone oil. However, it does not seem useful to exceed a volume fraction of 10% since K L a IPB decreases sharply at higher proportions of silicone oil. K L a IPB and K L a O2 evolve in the same way with the proportion of silicone oil. These results confirm the potentialities of our bioreactor to improve both the oxygen and pollutant gas transfer in the field of the treatment of gaseous pollutants, even for highly concentrated effluents. 相似文献
32.
Kevers C Jacques P Gaspar T Thonart P Dommes J 《Journal of chromatographic science》2004,42(10):554-558
The ginsenoside content of different ginseng species (Panax ginseng, P. quinquefolium, and P. vietnamensis) from different sources (roots from field-grown plants or from in vitro cultures, cells from solid calluses or from liquid cultures, commercial powders, and suspensions) is evaluated by means of a new high-performance thin-layer chromatography (HPTLC) technique combining an automatic TLC sampler and scanner. The results are compared with those obtained through more classical gross spectrometric and high-performance liquid chromatography (HPLC) techniques. HPTLC and HPLC allow the separation and estimation of the different ginsenosides. For this, HPTLC is faster and simpler than HPLC. Both techniques determine less amounts of ginsenosides than spectrophotometry, which displays overestimated values caused by light absorption by contaminating osides. In vitro cultured cells and roots contain the same ginsenosides as those produced by their mother plants, although at quite lower levels. The culture media also accumulates ginsenosides. 相似文献
33.
In a previous publication, we described a continuous production ofd-fructose from enzymatic hydrolysis of inulin with immobilized permeabilized cells (1).Kluyveromyces fragilis ATCC 12424 have been shown to possess inulase activity. The half life of the reactor was at least 1300 h, but productivity
was relatively low (around 40 g/L/day).
A selection of 50 mutants was tested on liquid medium for a possible increase of productivity.
In relation to the improvement of the reactor, the most important factor is intracellular inulase activity, and this activity
was increased with the KF 28 mutant.
Productivity reached 2000 g/L/day with the increase (of the productivity), proportional to the increase of intracellular inulase
activity. 相似文献
34.
Ahimou F Boonaert CJ Adriaensen Y Jacques P Thonart P Paquot M Rouxhet PG 《Journal of colloid and interface science》2007,309(1):49-55
The surface chemical composition of nine strains of Bacillus subtilis was determined by X-ray photoelectron spectroscopy. Regressions between elemental concentrations and concentrations associated with different components of C1s, N1s, and O1s peaks provided a more precise validation of the procedure used for peak decomposition and allowed the assignment of the peak components to be completed or strengthened. The component of the O1s peak appearing around 531.2 eV was shown to contain a contribution of oxygen from phosphate groups (PO, PO-), the other contribution being due to oxygen involved in amide functions. The surface negative charge may be fully attributed to phosphate groups, despite the observation of two types of zeta potential vs pH curves. The strains exhibiting a sharp variation of the zeta potential (range of -35 to -55 mV) between pH 2 and 4.7 were characterized by a high phosphate surface concentration and by an excess (about 25%) of phosphate with respect to the sum of potassium, an exchangeable cation, and protonated nitrogen, attributed to protein or to alanine involved in teichoic acids. 相似文献
35.
Alloue WA Destain J El Medjoub T Ghalfi H Kabran P Thonart P 《Applied biochemistry and biotechnology》2008,150(1):51-63
The purpose of this study was to immobilize lipase from Yarrowia lipolytica using three methods including inclusion, adsorption, and covalent bond to study enzyme leaching, storage, and catalytic properties. Sodium alginate and chitosan were the polymers selected to immobilize lipase by inclusion. The beads of each polymer were dried by freeze drying and fluidization. The results show that chitosan was more adapted to the inclusion of lipase. Even though freeze dried, bead activity was low compared to that of fluidized beads. The freeze-drying process seems to produce suitable beads for storage at 4 and 20 degrees C. The immobilization by adsorption was carried out on both celite and silica gel. Maximum immobilization yield of 76% was obtained with celite followed by 43% in silica gel. The enzyme adsorbed on the two supports exhibited greater stability at a certain temperature (50 degrees C) and in no polar solvents (Isooctane, n-heptane, and n-hexane). In addition, the lipase immobilized by covalent bond retained residual activity equitable to 70%. It was demonstrated that the enzyme immobilized by covalent bond showed greater activity (80%) after 5 months of storage. 相似文献
36.
Jean-Marc Aldric Jacqueline Destain Philippe Thonart 《Applied biochemistry and biotechnology》2005,122(1-3):707-719
Research was carried out to develop a biphasic biologic reactor able to clean the gas effluents polluted by volatile organic
compounds. Initially, Rhodococcus erythropolis T 902.1 was selected on the basis of its capacity to degrade isopropylbenzene (IPB). The effect of gas flow and IPB concentration
on the biodegadation of IPB was evaluated. The results show that the use of silicon oil allows large quantities of IPB to
be absorbed within the medium of biologic abatement. On the other hand, the biodegradation rate was directly correlated to
the inlet flow of IPB. Thus, the reactor presents interesting opportunities for the biologic treatment of gas effluents. 相似文献
37.
Baré G. Delaunois V. Rlkir R. Thonart Ph. 《Applied biochemistry and biotechnology》1994,45(1):599-610
Applied Biochemistry and Biotechnology - Pseudomonas fluorescens strain BTP9 is used as biocatalyst to produce vanillic acid from vanillin. Several two-phase reactors were investigated and compared... 相似文献
38.
A. Etoc F. Delvigne J. P. Lecomte P. Thonart 《Applied biochemistry and biotechnology》2006,130(1-3):392-404
In this article, we describe the development of a simple laboratory test for the effective screening of foam control agents
on a selected fermentation system, the mass production of Yarrowia lipolytica. Aeration testing is based on sparging air in the foaming medium allowing partial reproduction of the gas-liquid hydrodynamic
encountered in bioreactors. “Dynamic sparge test”, for which measurements are made during foam formation, was used to compare
the capacity of three antifoams, based on different technologies, to control the foam produced in the fermentation broth.
The selected foam control agents were: (1) an organic antifoam (TEGO AFKS911), (2) a siliconebased emulsion containing in
situ treated silica (DC-1520) and (3) a silicone/organic blend silica-free formulation. The testing results demonstrated dramatic
differences among them and showed that the capacity of TEGO AFKS911 and DC-1520 to control the foam generated in the fermentation
broth decreases as a function of fermentation time. This occurred to a much lesser extent for the silicone/organic blend formulation.
These results were correlated with the change of the foam nature and the increase of foam stability of the fermentation broth
with culture time. The increase in protein content as a function of growth time was correlated with an increase in foam stability
and antifoam consumption. A “synthetic fermentation broth” was also developed, by adding both proteins and microorganism to
the culture medium. This allowed us to mimic the fermentation broth, shown by the similar antifoams behaviour, and is therefore
a simple methodology useful for the selection of appropriate antifoams. 相似文献
39.
Bare G. Gerard J. Jacques ph. Delaunois V. Thonart Ph. 《Applied biochemistry and biotechnology》1992,34(1):499-510
Applied Biochemistry and Biotechnology - The ability of a fluorescentPseudomonas to bioconvert vanillin, a phenolic compound, into vanillic acid was investigated. Free and immobilized cell reactors... 相似文献
40.
Assamoi AA Destain J Delvigne F Lognay G Thonart P 《Applied biochemistry and biotechnology》2008,145(1-3):87-98
Xylanase is produced by Penicillium canescens 10–10c from soya oil cake in static conditions using solid-state fermentation. The impact of several parameters such as the nature
and the size of inoculum, bed-loading, and aeration is evaluated during the fermentation process. Mycelial inoculum gives
more production than conidial inoculum. Increasing the quantity of inoculum enhances slightly xylanase production. Forced
aeration induces more sporulation of strain and reduces xylanase production. However, forced moistened air improves the production
compared to production obtained with forced dry air. In addition, increasing bed-loading reduces the specific xylanase production
likely due to the incapacity of the Penicillium strain to grow deeply in the fermented soya oil cake mass. Thus, the best cultivation conditions involve mycelial inoculum
form, a bed loading of 1-cm height and passive aeration. The maximum xylanase activity is obtained after 7 days of fermentation
and attains 10,200 U/g of soya oil cake. These levels are higher than those presented in the literature and, therefore, show
all the potentialities of this stock and this technique for the production of xylanase. 相似文献