Sugars separation in a fermentative broth by simulated moving bed chromatography : SMB

Des sucres tels que les fructo-oligosaccharides (FOS) sont bénéfiques pour leurs hôtes car ils stimulent la croissance de bactéries bénéfiques dans le colon du fait qu’ils ne sont pas digérés par l’organisme. Ces FOS peuvent être produits à grande échelle par un procédé de fermentation du sucrose dont le milieu résultant (FOS + autres sucres + sels) doit être séparé en ses différents constituants afin de respecter les normes agroalimentaires. Parmi les techniques permettant cette séparation, seule la chromatographie liquide est applicable à grande échelle afin d’obtenir les puretés requises. La technique de séparation par lit mobile simulé (Simulated Moving Bed – SMB) permet de rendre le procédé continu et de diminuer la consommation d’éluant tout en augmentant la productivité. L’efficacité des techniques chromatographiques dépendant en grande partie de la nature de l’adsorbant, une étude préliminaire a été réalisée dans le but d’identifier le meilleur adsorbant pour cette séparation. Une résine échangeuse d’ions choisie, différentes techniques d’identification des paramètres de fonctionnement ont été mises en oeuvre afin de tester la séparation en mode SMB. Les résultats obtenus permettent de montrer qu’à partir d’un milieu de fermentation contenant 40% de FOS, il est possible d’obtenir un produit final pur à plus de 80%. Néanmoins, il a été mis en évidence que si la présence de sucrose dans le milieu de fermentation est inévitable, il faut absolument la contrôler au maximum pour éviter la pollution du produit finalFructooligosaccharides (FOS) are non-digestible sugars which affect positively the host by stimulating the growth of specific bacteria in the colon. At large scale, FOS can be produced from sucrose through fermentation. The fermentative broth obtained from this process is a complex mixture. The application of these sugars in the food industry requires their fractionation in order to meet final product specifications. Simulated moving bed chromatography (SMB) appears to be an efficient downstream process for the fractionation of sugars at an industrial scale. Thanks to this technique it is possible to work continuously reducing the solvent consumption and increasing the productivity. The major challenge when designing the separation process is the choice of an efficient adsorbent. A preliminary study was thus realized in order to identify the best adsorbent. An ion exchange resin was chosen and several parametric identification techniques were performed in order to realize the SMB separation. The results display the possibility to increase the FOS purity from 40% to 80%. Nevertheless, it was also displayed that sucrose present in the broth troubles the separation and must be strictly controlled during the fermentation

Operating conditions of a simulated moving bed chromatography unit for the purification of fructooligosaccharides

C. Nobre acknowledges the F.C.T. - Fundacao para a Ciencia e a Tecnologia (Portugal) for the PhD Grant ref. SFRH/BD/32514/2006. A. Severino is funded by Belgian Fund for Scientific Research (F.S.R.- FNRS).This paper presents research results of the Belgian Network DYSCO (Dynamical Systems, Control, and Optimization), funded by the Interuniversity Attraction Poles Programme, initiated by the Belgian Federal Science Policy Office (BELSPO). The scientific responsibility rests with its authors

Microbial treatment approaches for high-purity fructo-oligosaccharides production

The production of high-purity fructooligosaccharides (FOS), known as prebiotics, by sucrose fermentation using whole microbial cells has been recently explored. At the end of the fermentation process, FOS are present in mixture with small saccharides that are known to have an inhibitory effect of transfructosylating enzymes and to decrease the prebiotic activity of the mixture. This issue can be overcome by reducing the small saccharides present in FOS broth, which can be done using a combined microbial treatment, among others, improving as well the further purification of FOS by Simulated Moving Bed (SMB) chromatography. The main goal of this work was the use of combined microbial treatment approaches to improve FOS production and enhance a high purity FOS content. Aureobasidium pullulans and Saccharomyces cerevisiae were used combined to produce FOS and reduce the small sugars in the culture, respectively. FOS-producing microorganism was used free, immobilized to a non-conventional carrier or encapsulated in Ca-alginate beads, in mixture with the non-oligosaccharides consuming microorganism, free or encapsulated in Ca-alginate beads. A factorial design, considering three different variables, was performed, to select the microbial treatment approach through which increased FOS levels and yields can be obtained. The 38 assays were performed in shaken-flasks and the most suitable one was scaled-up to a 3L bioreactor. The inoculation time of S. cerevisiae showed to be the most relevant variable for FOS production, and the use of immobilized A. pullulans, mixed with encapsulated S. cerevisiae inoculated after 20h of fermentation, was the best combination, with statistical relevance (p<0.01), to obtain enhanced FOS concentration, percentage in the medium, yield and productivity. Results in bioreactor showed a higher fermentation time (20 to 25h) needed to obtain an increased maximal production of FOS (around 132 g.L-1) and yielded 0.70 ± 0.05 g of FOS per gram of initial sucrose. Also, the approach selected improved the percentage of FOS in the medium throughout the fermentation time, providing a pre-purified broth, with lower levels of mono-saccharides for further purification by SMB

MIL-91(Ti), a small pore metal-organic framework which fulfils several criteria : an upscaled green synthesis, excellent water stability, high CO2 selectivity and fast CO2 transport

The research leading to these results has received funding from the European Community Seventh Framework Program (FP7/2007-2013) [grant agreement number 608490] (project M4CO2) and from the ANR ‘CHESDENS’ (ANR-13-SEED-0001-01).A multidisciplinary approach combining advanced experimental and modelling tools was undertaken to characterize the promises of a small-pore type Ti-based metal-organic framework, MIL-91(Ti) for CO2 capture. This material was prepared using two synthesis strategies, i.e. under hydrothermal conditions and under reflux, and its single component adsorption behaviour with respect to CO2, CH4 and N2 was first revealed by gravimetry measurements. This hydrophilic and highly water stable MOF is characterized by a relatively high CO2 adsorption enthalpy. Molecular simulations combined with in situ powder X-ray diffraction evidenced that this is due to the combined interaction of this probe with N-H and P-O groups in the phosphonate linker. High CO2 selectivities in the presence of either N2 or CH4 were also predicted and confirmed by co-adsorption measurements. The possibility to prepare this sample under reflux represents an environmentally friendly route which can easily be upscaled. This green synthesis route, excellent water stability, high selectivities and relatively fast transport kinetics of CO2 are significant points rendering this sample of utmost interest for CO2 capture.PostprintPostprintPeer reviewe

Microbial co-culturing strategies for fructo-oligosaccharide production

Fructo-oligosaccharide (FOS) mixtures produced by fermentation contain large amounts of non-prebiotic sugars. Here we propose a mixed culture of Aureobasidium pullulans and Saccharomyces cerevisiae cells to produce FOS and consume the small saccharides simultaneously, thereby increasing FOS purity in the mixture. The use of immobilised A. pullulans in co-culture with encapsulated S. cerevisiae, inoculated after 10h fermentation, enhanced FOS production in a 5L bioreactor. Using this strategy, a maximal FOS concentration of 119g L1, and yield of 0.59gFOS gsucrose1, were obtained after 20h fermentation, increasing FOS productivity from about 4.9 to 5.9gFOS L1h1 compared to a control fermentation of immobilized A. pullulans in monoculture. In addition, the encapsulated S. cerevisiae cells were able to decrease the glucose in the medium to about 7.6% (w/w) after 63h fermentation. This provided a final fermentation mixture with 2.0% (w/w) sucrose and a FOS purity of over 67.0% (w/w). Moreover, a concentration of up to 58.0g L1 of ethanol was obtained through the enzymatic transformation of glucose. The resulting pre-purified FOS mixture could improve the separation and purification of FOS in downstream treatments, such as simulated moving bed chromatography.Cristiana C. Castro gratefully acknowledges the financial support from the F.R.S.-FNRS, the Belgium National Fund for Scientific Research (PDR: T.0196.13). Clarisse Nobre acknowledges the Portuguese Foundation for Science and Technology (FCT) for the postdoctoral grant (reference SFRH/BPD/87498/2012) and the strategic funding of the UID/BIO/04469/2013 unit, Project ColOsH 02/SAICT/ 2017 (POCI-01-0145-FEDER-030071), COMPETE 2020 (POCI-01-0145FEDER-006684), and BioTecNorte operation (NORTE-01-0145-FEDER000004), funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Организационно-управленческие инновации для снижения брака в ТОО фирма «Углемеханизация»

Цель работы- разработка рекомендаций для снижения брака в ТОО фирма "Углемеханизация". Объектом исследования является бракованная продукция. Предметом исследования являются способы минимизации брака на производстве. Актуальность темы исследования обусловлена тем, что хоть бракованная продукция и является естественной частью любого производства, отсутствие своевременных профилактических мер для минимизации брака способно привести к упущению прибыли, которую предприятие могло получить за качественную продукцию, и к снижению его конкурентоспособности.The purpose of the work is to develop recommendations to reduce scrap in the company "Углемеханизация" LLP. The object of the study is defective products. The subject of the study is the ways to minimize production defects. The relevance of the study of topic is due to the fact that although defective products are a natural part of any production, the lack of timely preventive measures to minimize defects can lead to a loss of profits that an enterprise could receive for quality products and to a decrease in its competitiveness

A Reference High-Pressure CO2 Adsorption Isotherm for Ammonium ZSM-5 Zeolite: Results of an Interlaboratory Study

© 2018, The Author(s). This paper reports the results of an international interlaboratory study led by the National Institute of Standards and Technology (NIST) on the measurement of high-pressure surface excess carbon dioxide adsorption isotherms on NIST Reference Material RM 8852 (ammonium ZSM-5 zeolite), at 293.15 K (20 °C) from 1 kPa up to 4.5 MPa. Eleven laboratories participated in this exercise and, for the first time, high-pressure adsorption reference data are reported using a reference material. An empirical reference equation nex=d(1+exp[(-ln(P)+a)/b])c, [nex-surface excess uptake (mmol/g), P-equilibrium pressure (MPa), a = −6.22, b = 1.97, c = 4.73, and d = 3.87] along with the 95% uncertainty interval (Uk = 2 = 0.075 mmol/g) were determined for the reference isotherm using a Bayesian, Markov Chain Monte Carlo method. Together, this zeolitic reference material and the associated adsorption data provide a means for laboratories to test and validate high-pressure adsorption equipment and measurements. Recommendations are provided for measuring reliable high-pressure adsorption isotherms using this material, including activation procedures, data processing methods to determine surface excess uptake, and the appropriate equation of state to be used

Adsorption of Carbon Dioxide, Methane, and Their Mixtures in Porous Carbons: Effect of Surface Chemistry, Water Content, and Pore Disorder

International audienceThe adsorption of carbon dioxide, methane, and their mixtures in nanoporous carbons in the presence of water is studied using experiments and molecular simulations. Both the experimental and numerical samples contain polar groups that account for their partially hydrophilicity. For small amounts of adsorbed water, although the shape of the adsorption isotherms remain similar, both the molecular simulations and experiments show a slight decrease in the CO2 and CH4 adsorption amounts. For large amounts of adsorbed water, the experimental data suggest the formation of methane or carbon dioxide clathrates in agreement with previous work. In contrast, the molecular simulations do not account for the formation of such clathrates. Another important difference between the simulated and experimental data concerns the number of water molecules that desorb upon increasing the pressure of carbon dioxide and methane. Although the experimental data indicate that water remains adsorbed upon carbon dioxide and methane adsorption, the molecular simulations suggest that 40 to 75% of the initial amount of adsorbed water desorbs with carbon dioxide or methane pressure. Such discrepancies show that differences between the simulated and experimental samples are crucial to account for the rich phase behavior of confined water-gas systems. Our simulations for carbon dioxide-methane coadsorption in the presence of water suggest that the pore filling is not affected by the presence of water and that adsorbed solution theory can be applied for pressures as high as 15 MPa

A dual resistance model to describe CO2 diffusion in ultra-microporous carbon molecular sieves,

International audienc