83 research outputs found
The use of date waste for lactic acid production by a fed-batch culture using <italic>Lactobacillus casei</italic> subsp. <italic>rhamnosus</italic>
Effect of Carbon Sources on Glutamate Production from Corynebacterium glutamicum 2262
A comparative study between natural and synthetic environments is carried out by realizing six fermentation experiments in batch culture. The objective of this study is to consider the effect of carbon sources on growth and the production of glutamic acid by Corynebacterium glutamicum 2262. The difference between the culture media lies in the carbon source. Two natural environments of date juice, one of which is treated with invertase to hydrolyse sucrose with a concentration of total sugars of 88 g/L. Four synthetic media with a concentration of 34 g/L sugars: medium containing mixed sugars (glucose + fructose + sucrose) with rates proportional to that of date juice, the other three media are composed of a single sugar (either glucose, fructose, or sucrose). The results showed that Corynebacterium glutamicum is able to use the three sugars whether they are single or mixed, although the best results of glutamate production (8.41 g/L) are obtained on the mixture of three sugars, which explains the interest and valorisation of date waste. On the other hand, the date juice-based media are shown to have a glutamate concentration of 7.98 g/L during the hydrolysis of sucrose of date juice
Utilization of prickly pear waste for baker's yeast production
The feasibility of baker's yeast production using fruits and peels of Opuntia ficus indica (OFI) as carbohydrate feedstock was investigated. Two response surface methodologies involving central composite face centered design (CCFD) were successfully applied. The effects of four independent variables on baker's yeast production from OFI fruit juice was evaluated using the first CCFD. The best results were obtained with 24 H of inoculum age, 30 degrees C temperature, 200 rpm of agitation, and 10% inoculum size. At the maximum point, the biomass concentration reached 9.29 g/L. A second CCFD was performed to optimize the sugar extraction from OFI fruit peels. The potential of these latter as a fermentation substrate was determined. From the experimental results, the OFI fruit peel is an appropriate carbon source for the production of baker's yeast. The maximum biomass concentration was 12.51 g/L. Different nitrogen supplements were added to promote the yields of baker's yeast. Corn steep liquor was found to be the best alternative nutrient source of casein hydrolysate and yeast extract for baker's yeast production.info:eu-repo/semantics/publishedVersio
Correlation of cell growth and heterologous protein production by Saccharomyces cerevisiae
With the increasing demand for biopharmaceutical proteins and industrial enzymes, it is necessary to optimize the production by microbial fermentation or cell cultures. Yeasts are well established for the production of a wide range of recombinant proteins, but there are also some limitations; e.g., metabolic and cellular stresses have a strong impact on recombinant protein production. In this work, we investigated the effect of the specific growth rate on the production of two different recombinant proteins. Our results show that human insulin precursor is produced in a growth-associated manner, whereas alpha-amylase tends to have a higher yield on substrate at low specific growth rates. Based on transcriptional analysis, we found that the difference in the production of the two proteins as function of the specific growth rate is mainly due to differences in endoplasmic reticulum processing, protein turnover, cell cycle, and global stress response. We also found that there is a shift at a specific growth rate of 0.1 h(-1) that influences protein production. Thus, for lower specific growth rates, the alpha-amylase and insulin precursor-producing strains present similar cell responses and phenotypes, whereas for higher specific growth rates, the two strains respond differently to changes in the specific growth rate
High production of L-glutamic acid from date juice extracts by Corynebacterium glutamicum using fed-batch cultures: pulsed and continuous feeding modes
In the present work, L-glutamic acid production by Corynebacterium glutamicum fermentation on date juice extracts applying two fed-batch feeding modes, pulsed and continuous, were investigated. According to the obtained results, the continuous feeding fed-batch mode was found to be the most efficient process. Moreover the continuous feeding rate mode with a feeding medium containing date juice sugars enriched with ammonium sulfate was found even more favorable as it enhances the L-glutamic acid production by approximately 2.35 fold more than the batch culture and by about 1.17 fold more than the pulsed feeding. In this respect, comparing the traditional batch culture to the continuously fed culture with a medium containing date juice sugars with ammonium sulfate showed increases of 135.47% in L-glutamic acid production, 104% in productivity, 39.09% in biomass, and 47.69% in the yield respectively allowing us to reach a final L-glutamic acid concentration of about 138 g/L, the highest ever published
Statistical Optimization of Dilute Acid Hydrolysis of Wood Sawdust for Lactic Acid Production
International audienc
Production of lactic acid by Lactobacillus casei subsp. rhamnosus on date juice : kinetic and optimisation during batch, fed-batch and continuous cultures
Lâobjectif de ce travail a Ă©tĂ© de dĂ©velopper un procĂ©dĂ© performant de production dâacide lactique par Lactobacillus casei subsp. rhamnosus sur jus de datte. Dans une premiĂšre partie, des cultures en mode discontinu ont Ă©tĂ© rĂ©alisĂ©es afin dâĂ©tudier les besoins nutritionnels de la souche. Ces Ă©tudes ont pour but de dĂ©crire les effets des sources carbonĂ©es, azotĂ©es et les vitamines sur la production dâacide lactique. Nous avons montrĂ© que le sulfate dâammonium est une bonne alternative Ă©conomique et nous avons pu dĂ©terminer la faisabilitĂ© de minimiser lâajout de lâextrait de levure par lâutilisation partielle de lâextrait de levure combinĂ©e avec du sulfate dâammonium plus lâajout de vitamines du groupe B. Des cultures pures et mixtes de Lactobacillus casei et Lactococcus lactis ont Ă©tĂ© rĂ©alisĂ©es. Le systĂšme de culture mixte donne de meilleurs rĂ©sultats concernant la production dâacide lactique et lâutilisation des sucres comparĂ©s Ă ceux obtenus en cultures pures de Lactobacillus casei ou Lactococcus lactis. Lâeffet des sucres purs (glucose et fructose) et mixtes (glucose/fructose) sur la production dâacide lactique a Ă©tĂ© Ă©tudiĂ©. La production dâacide lactique est plus importante avec un mĂ©lange de sucres quâavec des sucres non mĂ©langĂ©s ce qui explique les performances de fermentation sur jus de datte. Dans une seconde partie, une stratĂ©gie dâalimentation du rĂ©acteur en culture semi-continue a Ă©tĂ© mise en Ćuvre, permettant dâamĂ©liorer les performances de la fermentation. Les deux facteurs influençant le bon fonctionnement sont le dĂ©bit et la concentration du milieu dâalimentation. Dans une troisiĂšme partie, une Ă©tude cinĂ©tique a Ă©tĂ© dĂ©veloppĂ©e en rĂ©acteurs continus. Nous avons Ă©tudiĂ© lâinfluence du taux de dilution sur la croissance, lâutilisation du substrat et la production dâacide lactique. La productivitĂ© du procĂ©dĂ© continu a Ă©tĂ© considĂ©rablement augmentĂ©e en comparaison avec le procĂ©dĂ© discontinu. Enfin, dans une derniĂšre partie, un modĂšle a Ă©tĂ© Ă©tabli. Ce modĂšle, bien quâimparfait, permet apparemment de simuler la croissance, la consommation des sucres de jus de datte et la production dâacide lactique en culture discontinueThe aim of this work was to develop an efficient process of lactic acid production by Lactobacillus casei subsp. rhamnosus on date juice In a first part, the batch cultures were realized to carry out the nutritional requirement of the strain. These studies allowed us to describe the effects of carbon substrates, nitrogen substrates and vitamins on the lactic acid production. We showed that ammonium sulphate is a satisfying economic alternative and we have determined feasibility of minimizing the addition of the yeast extract by the partial use of yeast extract combined with the ammonium sulphate plus the addition of vitamins of the group B. Pure and mixed cultures of Lactobacillus casei and Lactococcus lactis were carried out. The mixed system gives better results concerning the lactic acid production and the use of the sugars compared with those obtained in pure cultures of Lactobacillus casei or Lactococcus lactis. The effect of pure sugars (glucose and fructose) and mixed sugars (glucose/fructose) on the lactic acid production was studied. The lactic acid production is more important on mixed sugars than on pure sugars what explains the performances of fermentation on date juice. In a second part, a mode of fed batch operations was defined to improve the performances of the fermentation. The two factors influencing the process are the feeding rate and the concentration of the feeding medium. In a third part, kinetic study in continuous culture was developed. We studied the influence of dilution rate on growth, substrate utilization and lactic acid production. The productivity of the continuous process was considerably increased in comparison with the batch process. Finally, a tentative model has been established for the fermentation process. The corresponding model, although not perfect, is apparently able to simulate growth rate, substrates uptake and lactic acid production in batch cultur
The use of date waste for lactic acid production by a fed-batch culture using <italic>Lactobacillus casei</italic> subsp. <italic>rhamnosus</italic>
International audienc
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