This work describes an original methodology to quantify complex peptide mixtures by size-exclusio... more This work describes an original methodology to quantify complex peptide mixtures by size-exclusion high-performance liquid chromatography (SE-HPLC). The methodology was first tested on simulated elutions of peptide mixtures. For this set of experiments, a good estimation of the total peptide concentration was observed (error less than 10 %). Then 30 fractions obtained by ultrafiltration of hydrolysates from two different sources were titrated by Kjeldahl or BCA analysis and analysed by SE-HPLC for an experimental validation of the methodology. Very good matchs between methods were obtained. The linear working range depends on the hydrolysate but is generally between 0.2 and 4gL(-1) (i.e. between 10 and 200μg). Moreover, the presence of organic solvents or salts in samples does not impact the accuracy of the methodology contrary to common quantification methods. Hence, the findings of this study show that total concentration of complex peptide mixture can be efficiently determinate by the proposed methodology using simple SE-HPLC analysis.
The aim of the present work is to study the potential of different Yeast Derived Nutrients (YDN) ... more The aim of the present work is to study the potential of different Yeast Derived Nutrients (YDN) as supplements in mammalian cell culture serum-free media. Firstly, a screening of six yeast derived nutrients has been performed on the cell growth of a recombinant CHO cell line producing γ-interferon, at small scale, in static cultures. The effects of YDN observed at
To limit contamination risks by animal-derived components, we designed a new serum-free medium su... more To limit contamination risks by animal-derived components, we designed a new serum-free medium supplemented with rapeseed peptidic fractions. Compared to a reference serum-free medium this new medium allows a 3-fold increase in cell density, a 2-times extended longevity, a 5 times higher final product titer, Modifications of glucose metabolism were also observed. Addition of free amino-acids did not lead to the same positive effect, suggesting that peptides act not only as carbon, nitrogen and energy source but also as growth or survival factors. This rapeseed fraction also allows a very simple formulation of a protein-free medium.
The production of carotenoids, lipid content, and fatty acid composition were all studied in a st... more The production of carotenoids, lipid content, and fatty acid composition were all studied in a strain of Sporobolomyces ruberrimus when using different concentrations of technical glycerol as the carbon source and ammonium sulfate as the nitrogen source. The total lipids represented an average of 13% of the dry weight, and the maximum lipids were obtained when using 65.5 g/l technical glycerol (133.63 mg/ g). The optimal conditions for fatty acid production were at 27 degrees C using 20 g of ammonium sulfate and a pH range from 6 to 7, which produced a fatty acid yield of 32.5+/-1 mg/g, including 1.27+/- 0.15 mg of linolenic acid (LNA), 7.50+/-0.45 mg of linoleic acid (LLA), 5.50+/-0.35 mg of palmitic acid (PA), 0.60+/-0.03 mg of palmitoleic acid (PAL), 1.28+/-0.11 mg of stearic acid (SA), 9.09+/-0.22 mg of oleic acid, 2.50+/-0.10 mg of erucic acid (EA), and 4.25+/-0.20 mg of lignoceric acid (LCA), where the palmitic, oleic, and linoleic acids combined formed about 37% of the total ...
Bioprocesses are appreciated as difficult to control because their dynamic behavior is highly non... more Bioprocesses are appreciated as difficult to control because their dynamic behavior is highly nonlinear and time varying, in particular, when they are operating in fed batch mode. The research objective of this study was to develop an appropriate control method for a complex bioprocess and to implement it on a laboratory plant. Hence, an intelligent control structure has been designed
The enzymatic acylation of polar dipeptides was investigated. First, the Novozym435®-catalyzed ac... more The enzymatic acylation of polar dipeptides was investigated. First, the Novozym435®-catalyzed acylation of Lys-Ser, HCl exhibiting three potential acylable sites was carried out in organic media (2-methyl-2-butanol, oleic acid) and in an ionic liquid ([Bmim]+[PF6]−). In these reactions, the chemo-selectivity of the acylation was exclusively in favour of the Nɛ-lysine acylation and the efficiency (substrate conversion) was demonstrated to be
This work describes an original methodology to quantify complex peptide mixtures by size-exclusio... more This work describes an original methodology to quantify complex peptide mixtures by size-exclusion high-performance liquid chromatography (SE-HPLC). The methodology was first tested on simulated elutions of peptide mixtures. For this set of experiments, a good estimation of the total peptide concentration was observed (error less than 10 %). Then 30 fractions obtained by ultrafiltration of hydrolysates from two different sources were titrated by Kjeldahl or BCA analysis and analysed by SE-HPLC for an experimental validation of the methodology. Very good matchs between methods were obtained. The linear working range depends on the hydrolysate but is generally between 0.2 and 4gL(-1) (i.e. between 10 and 200μg). Moreover, the presence of organic solvents or salts in samples does not impact the accuracy of the methodology contrary to common quantification methods. Hence, the findings of this study show that total concentration of complex peptide mixture can be efficiently determinate by the proposed methodology using simple SE-HPLC analysis.
The aim of the present work is to study the potential of different Yeast Derived Nutrients (YDN) ... more The aim of the present work is to study the potential of different Yeast Derived Nutrients (YDN) as supplements in mammalian cell culture serum-free media. Firstly, a screening of six yeast derived nutrients has been performed on the cell growth of a recombinant CHO cell line producing γ-interferon, at small scale, in static cultures. The effects of YDN observed at
To limit contamination risks by animal-derived components, we designed a new serum-free medium su... more To limit contamination risks by animal-derived components, we designed a new serum-free medium supplemented with rapeseed peptidic fractions. Compared to a reference serum-free medium this new medium allows a 3-fold increase in cell density, a 2-times extended longevity, a 5 times higher final product titer, Modifications of glucose metabolism were also observed. Addition of free amino-acids did not lead to the same positive effect, suggesting that peptides act not only as carbon, nitrogen and energy source but also as growth or survival factors. This rapeseed fraction also allows a very simple formulation of a protein-free medium.
The production of carotenoids, lipid content, and fatty acid composition were all studied in a st... more The production of carotenoids, lipid content, and fatty acid composition were all studied in a strain of Sporobolomyces ruberrimus when using different concentrations of technical glycerol as the carbon source and ammonium sulfate as the nitrogen source. The total lipids represented an average of 13% of the dry weight, and the maximum lipids were obtained when using 65.5 g/l technical glycerol (133.63 mg/ g). The optimal conditions for fatty acid production were at 27 degrees C using 20 g of ammonium sulfate and a pH range from 6 to 7, which produced a fatty acid yield of 32.5+/-1 mg/g, including 1.27+/- 0.15 mg of linolenic acid (LNA), 7.50+/-0.45 mg of linoleic acid (LLA), 5.50+/-0.35 mg of palmitic acid (PA), 0.60+/-0.03 mg of palmitoleic acid (PAL), 1.28+/-0.11 mg of stearic acid (SA), 9.09+/-0.22 mg of oleic acid, 2.50+/-0.10 mg of erucic acid (EA), and 4.25+/-0.20 mg of lignoceric acid (LCA), where the palmitic, oleic, and linoleic acids combined formed about 37% of the total ...
Bioprocesses are appreciated as difficult to control because their dynamic behavior is highly non... more Bioprocesses are appreciated as difficult to control because their dynamic behavior is highly nonlinear and time varying, in particular, when they are operating in fed batch mode. The research objective of this study was to develop an appropriate control method for a complex bioprocess and to implement it on a laboratory plant. Hence, an intelligent control structure has been designed
The enzymatic acylation of polar dipeptides was investigated. First, the Novozym435®-catalyzed ac... more The enzymatic acylation of polar dipeptides was investigated. First, the Novozym435®-catalyzed acylation of Lys-Ser, HCl exhibiting three potential acylable sites was carried out in organic media (2-methyl-2-butanol, oleic acid) and in an ionic liquid ([Bmim]+[PF6]−). In these reactions, the chemo-selectivity of the acylation was exclusively in favour of the Nɛ-lysine acylation and the efficiency (substrate conversion) was demonstrated to be
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