Papers by jean noel barbotin
L'invention concerne une composition pour encapsuler des microorganismes ou des enzymes dans ... more L'invention concerne une composition pour encapsuler des microorganismes ou des enzymes dans des capsules, contenant, en dehors des microorganismes ou enzymes, 0, 5 a 20 % en poids d'un polysaccharide naturel, par exemple un alginate, 4 a 20 % en poids d'un agent de flottabilite, par exemple de l'huile de paraffine, de 1, 5 a 5 % en poids d'un agent d'elasticite gelifiable, par exemple de l'alcool polyvinylique, le complement a 100 % etant de l'eau.Les capsules flottantes obtenues sont notamment utilisees dans des reacteurs de traitement de l'eau mettant en oeuvre des lits flottants fixes, turbulents ou circulants.
Applied and Environmental Microbiology, 1983
Growing Bacillus subtilis cells were immobilized in k -carrageenan gel beads. Growth and sporulat... more Growing Bacillus subtilis cells were immobilized in k -carrageenan gel beads. Growth and sporulation of entrapped cells were studied by two different methods: cell enumeration and transmission electron microscopy. Immobilized growing cells had a shorter generation time than free cells did, whereas sporulation timing was unchanged. When steady state was reached, cell density was very high in gel beads.
Colloids and Surfaces, 1984
ABSTRACT
European Journal of Biochemistry, 1999
The pathways of polysaccharide biosynthesis were investigated in cells of Sinorhizobium meliloti ... more The pathways of polysaccharide biosynthesis were investigated in cells of Sinorhizobium meliloti (strain Su47) using a stable isotope approach. The isotopic labeling of the periplasmic beta-1,2-glucans synthesized from glucose labeled at various positions evidenced the involvement of catabolic pathways, namely the pentose-phosphate and Entner-Doudoroff pathways, into the early steps of polysaccharide synthesis. The exopolysaccharides produced at the same time had a labeling pattern similar to that of the beta-glucans, indicating similar early steps for both polysaccharides. The results emphasized a cyclic organization of the carbohydrate metabolism in S. meliloti, in which the carbons of the initial hexose were allowed to re-enter the catabolic pathways many times. The metabolic incidences of such metabolic topology are discussed.
Physiologia Plantarum, 1985
... entrapped in a calcium alginate gel Christian Tanipoiinel, Fran<;oi.s Costantiiio, Jean-No... more ... entrapped in a calcium alginate gel Christian Tanipoiinel, Fran<;oi.s Costantiiio, Jean-Noel Barbotin and Rej^is Calvayrac ... In addition, long term storage (2 years) iti cal-cium alginate has been performed permitting appliealions in algal storage. ...
Journal of Biotechnology, 1987
Journal of Biotechnology, 2000
FEMS Microbiology Reviews, 1994
Immobilized cells can adopt different densities, distributions and growth patterns inside polysac... more Immobilized cells can adopt different densities, distributions and growth patterns inside polysaccharidc gel beads. Thcsc arrangements are closely related to both the morphological characteristics of a given cell strain and the internal structure o] the gc[ bead. We have encountered different kinds of structural inhomogeneities (e.g. superficial crusts, radial shafts and microchanncls, discrete cavities, concentric ordered gel block layers, amorphous gel blocks, random fractures, etc.) in polysaccharide gel beads while working under different experimental conditkms. These snpramacromolecular structures are important factors to take into account for the development of microorganisms inside the gel matrix and for the utilization of immobilized cells as biocatalysts.
FEBS Letters, 2001
Recycling of triose-phosphate and pentose-phosphate was previously reported on glucose in Sinorhi... more Recycling of triose-phosphate and pentose-phosphate was previously reported on glucose in Sinorhizobium meliloti, a polysaccharide-synthesizing bacterium, but the metabolic basis of such processes remained unclear. In this work, we have used 13 C-labelling strategies to demonstrate that carbohydrate cycling in this organism is independent of the gluconate bypass, the alternative pathway for glucose assimilation involving its periplasmic oxidation into gluconate. Furthermore, carbohydrate cycling in S. meliloti is also observed on fructose, making the situation in this bacterium significantly different from that depicted for alginate-synthesizing species.
Enzyme and Microbial Technology, 1981
... Microbiol. 1975, 105,207 12 Kierstan, M. and Bucke, C. Biotechnol, Bioeng, 1977, 19, 387 13 O... more ... Microbiol. 1975, 105,207 12 Kierstan, M. and Bucke, C. Biotechnol, Bioeng, 1977, 19, 387 13 Ohlson, S., Larsson, PO and Mosbach, K. Eur. J. Appl. Microbiol. Biotechnol 1979, 7, 103 14 Lowry, OH, Rosebrough, NJ, Fair, AL and Randall, RJJ Biol. Chem. ...
Canadian Journal of Microbiology, 1987
To mimic the behavior of the denitrifying marine bacterium Pseudmonas nautica 617 in sediment, we... more To mimic the behavior of the denitrifying marine bacterium Pseudmonas nautica 617 in sediment, we used immobilized cells in a carrageenan gel. This procedure was very useful to simulate the water-filled, anaerobic microspaces between sediment particles. The growth and nitrate reduction of this organism has been investigated with free and immobilized cells. The generation time in gel beads was 1.7 h as compared with 2.4 h for free cells. The nitrate reduction activity for the free and immobilized cells was 4.6 and 7 μmol [Formula: see text] transformed∙h−1∙mg protein−1, respectively. Cell growth in the gel has been followed by electron microscopy.
Biotechnology and Bioengineering, 1986
This article deals with aspects of the reciprocal interaction between the activity of chloroplast... more This article deals with aspects of the reciprocal interaction between the activity of chloroplast membranes and their microenvironment. The artificial matrices used in the present work to immobilize thylakoids (albuminglutaraldehyde matrix, polyurethane foam) can be regarded as weak ion exchangers. Thus, the distribution of the solute between the matrix surface and the external solution should, at least in part, be governed by a Donnan equilibrium. The influence of a high ionic strength medium (750mM potassium citrate) on the kinetic parameters (Kp, V,,,) and on the stability of the photosynthetic activity of immobilized chloroplast membranes has been studied. The results show similarities in behavior of the two supports studied in that, for both, a high concentration of salt (citrate) increases the apparent affinity for ferricyanide and allows a better transformation of this electron acceptor in CSTR experiments.
Biochimica et Biophysica Acta (BBA) - Biomembranes, 1988
Applied Optics, 1982
Chloroplasts immobilized in proteins, polysaccharides, and organic polymers are studied in terms ... more Chloroplasts immobilized in proteins, polysaccharides, and organic polymers are studied in terms of activity yield and functional stability under continuous work, using the relative changes in PAS spectra. II. Materials and Methods A. Biological Material (Lettuce Thylakoids) Obtained as described in Refs. 3 and 4.
Applied Microbiology and Biotechnology, 1984
Growing Escherichia coli BZ18/pTG 201 cells were immobilized in Kappa-carrageenan gel beads. The ... more Growing Escherichia coli BZ18/pTG 201 cells were immobilized in Kappa-carrageenan gel beads. The bacterial growth after immobilization was studied by cellular counting and by morphological observations with electron microscopy. Kinetic studies of the Catechol 2-3 dioxygenase carried by the plasmid pTG 201 were performed with a packed-bed reactor to show the potential of such a system. High cell densities 1.7 x 1011 cells/ml) were observed in the cavities of the gel. Due to the difference between the cell density in suspension (8 x 108 cells/ml) and that within the gel cavities, a reduction of the reactor size and investment cost for processes can be predicted.
Applied Microbiology and Biotechnology, 1984
Stability studies of photosynthetic activity under continuous saturating illumination are present... more Stability studies of photosynthetic activity under continuous saturating illumination are presented. Chloroplast membranes (thylakoids) are isolated in a classical Hepes/sorbitol buffer or in high salt concentration buffers (citrate or sulphate) and then immobilized in a co-crosslinking serum albumin-glutaraldehyde matrix. The activities of these immobilized systems tested in a batch reactor are greatly increased by high concentrations of salts (223 and
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Papers by jean noel barbotin