Gomba eredetű inulináz enzim termelése és tanulmányozása = Production and study of inulinase from fungi

Kutatási munkáink az inulint bontó inulináz enzimre fókuszáltak. Megvizsgáltuk 10 Thermomyces lanuginosus fonalasgomba, 15 Kluyveromyces élesztő és 5 Bifidobacterium törzs extracelluláris inulináz enzimtermelő képességét és kiválasztottuk a legjobb törzseket a további vizsgálatokra. Különböző optimálási technikák alkalmazásával sikerült a tápközeg összetételének mennyiségi és minőségi optimálása, amely alkalmas az inulináz enzim termelésére a T. lanuginosus IMI 140524 és Kl. thermotolerans Y00715 törzsek fermentációjával. A laboratóriumi fermentorban történő inulináz enzim előállítására meghatároztuk a fermentáció optimális körülményeit (inokulum kora és mennyisége, keverés és levegőztetés, tápközeg kezdeti pH stb.). Soklépéses módszert dolgoztunk ki az inulináz enzim homogenitásig történő tisztítására. Meghatároztuk a tisztított inulináz enzim működési és kinetikai paramétereit, valamint vizsgáltuk az enzim stabilitását. Módszert dolgoztunk ki az inulináz enzim rögzítésére és a biokonverziót modelleztük mind a szabad, mind a rögzített enzim alkalmazásával. Sikerült megtervezni, felépíteni és optimálni egy 25 ml-es töltött ágyas rögzített enzimes bioreaktort, amely alkalmazásával megvalósítható a folytonos biokonverzió. Az általunk kidolgozott rendszer alkalmazásával az inulin részleges vagy teljes biokonverziója révén frukto-oligoszacharidok vagy fruktóz szirup állítható elő, amely fontos szerepet játszik az élelmiszer és a gyógyászati iparban is. | Our research had focused on inulinase that is able to break down inulin. Ten Thermomyces lanuginosus filamentous fungi, 15 Kluyveromyces and 5 Bifidobacterium strains were screened for extracellular inulinase enzyme production and the best strains were selected for further studies. New fermentation medium was successfully developed using optimization technology (both quantity and quality) for production of inulinase using the selected T. lanuginosus IMI 140524 and Kl. thermotolerans Y00715 strain. Furthermore, the optimum fermentation conditions (age and quantity of inoculum, mixing and aeration, the initial pH of culture medium, etc.) were also determined for inulinase fermentation in the laboratory fermentor. Protocol contained several chromatographical steps was developed for isolation and purification of enzyme protein to homogeneity. Optimal operational and kinetic parameters as well as stability of purified enzyme were determined. Method was developed to immobilization of inulinase into chitin carrier and bioconversion of inulin was carried out applying both free and immobilized enzyme preparation. Continuous bioconversion system containing pack-bed immobilized enzyme bioreactor (25 ml working volume) was designed, created and modelled. This system could be exploited for the continuous production of oligofructose or fructose from either Jerusalem artichoke juice or inulin. These products play an important role in the food and medical industries

IMPACT ASSESSMENT OF THE EXTENDED PRODUCTION RESPONSIBILITY IMPLEMENTATION IN VIETNAM: A STUDY ON ELECTRONIC WASTE MANAGEMENT

The electronic waste is now raised in Vietnam as emerging issue, not only by its impact on the environment and public health, but also the chance to utilize the natural resources. In order to sustainable management of major urban-mine sources, including e-waste, an Extended Producer Responsibility (EPR) system is proposed under the Decision 16/QĐ-TTg dated 22, May, 2015, to extend the responsibility of producers to the end-of-life product. In this study, the Material Flow Analysis and Policy assessment tool are applied to assess the impact of the EPR system, in case of large home appliances and to find the obstacles on the implementation of the system. Among the experimental appliances, air conditioner has the highest rate of valuable materials and also the highest rate of recyclable materials, then follows the refrigerator, washing machine and desktop computer. On the opposite, Cathode Ray Tube (CRT) monitor has the highest rate of hazardous compounds, where washing machine has no hazardous matter. Three scenarios were developed and assessed based on the obtained benefit–cost from dismantled material and hazardous waste. It is shown that the role of intermediate stakeholders, the infrastructure for e-waste treatment and monetary distribution flows under the pressure of legislation are the main factors that caused failure in the application of the EPR system in Vietnam

Innovation and Export of Vietnam’s SME Sector

Innovation has long been considered an important factor for creating and maintaining the competitiveness of nations and firms. The relationship between innovation and exporting has been investigated for many countries. However, there is a paucity of research in Vietnam with respect to this issue. In this paper we examine whether innovation performed by Vietnam’s small and medium enterprises (SMEs) enhances their exporting likelihood. Using the recently released Vietnam Small and Medium Enterprise Survey 2005, we find that innovation as measured directly by ‘new products’, ‘new production process’ and ‘improvement of existing products’ are important determinants of exports by Vietnamese SMEs.Vietnam; Export; Innovation; Small and Medium Enterprise

Economic performance of Vietnam, 1976-2000: New evidence from input-output model

This study provides a concise introduction to the economic history of Vietnam from 1976 to present. We identify different phases of the development of the Vietnamese economy, from its unification after a Vietnam war to the current phases of the transition (1989-2000) and propose a specific pattern of transition in the case of Vietnam. This research is the first attempt to make a synthesis quantitative analysis of socio-economic aggregate data during different phases of the Vietnamese economy in 1986-2000, in which different national input-output tables (1989, 1996 and 2000) in constant prices have been employed. The economic performances are investigated from three aspects: (i) evolution of domestic final demand; (ii) evolution of international trade structure and (iii) the technological change. The analysis shows economic history of Vietnam from 1986 up to present as a continuous evolutionary process and integration in to the international market is inevitable. Government programmes only played a vital role of accommodator to the economic changes of the Vietnamese economy.Input-output analysis, Vietnamese economy, Economic history, Transition economy, Macro-economic policy

Affections of Turbine Nozzle Cross-Sectional Area to the Marine Diesel Engine Working

After a long period of use, some important technical parameters of the main marine diesel engines (MDE) gradually become worse, such as the turbine speed, intake pressure, exhaust temperature, engine power, and specific fuel oil consumption (SFOC). This paper studies the affections of the turbine nozzle cross-sectional area (AT) to MDE and presents a method of AT adjustment to improve the performances of MDE. A mathematical model of an engine was built based on the existent engine construction and the theory of the diesel engine working cycle and the simulation was programmed by Matlab/Simulink. This simulation model accuracy was evaluated through the comparison of simulation results and experimental data of the MDE. The accuracy testing results were acceptable (within 5%). The influences of AT on the engine working parameters and the finding optimization point were conducted by using the simulation program to study. The predicted optimization point of the nozzle was used to improve the engine’s performances on board. The integration of the simulation and experiment studies showed its effectiveness in the practical application of the marine diesel engine field

Optimizing engineering analysis resource allocation

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; in conjunction with the Leaders for Manufacturing Program at MIT, 2001.Includes bibliographical references (p. 72-73).by Quang Nguyen.S.M.M.B.A

Étude comparative expérimentale des opérations d’atomisation et d’autovaporisation : application à la gomme arabique et au soja

Nowadays, the need to achieve long term stability and usability, in addition to greater functionality, implies that many food products and liquid or solid ingredients are dehydrated or mechanically transformed into powder. The manufacturing processes of food powders always require the satisfaction of a series of criteria, such as process performance and product quality. The spray drying technology is always considered the main method used for producing the powders in many varied fields thanks to its preponderant advantages. However, in some cases, the spray drying shows less effective because the initial investment and production costs are too high ; the need to reach a large specific surface area of the powders causes a lot of complex problems relating to the transportation, cleaning, product recovery, explosion risk and thermal degradation of final product. Whereas, many research work on the autovaporization phenomenon by DIC (Instant controlled pressure drop) showed that the DIC technology is able to solve many industrial problems, eventually leading to obtaining the very high-quality finished products and reducing the energy consumption. However, applications of the DIC technology in the manufacture of food powders are still restricted, and the comparison of the properties of the powder obtained by DIC with other production methods is not yet performed systematically. In such a context, this thesis work is performed in order to contribute to solving some problems concerning the control and improvement of the food powder quality as well as the heat transfer efficiency in the spray drying and autovaporization operations (DIC treatment). In order to attain these objectives, two main raw materials consisting of gum arabic and soybean were examined. Five main researches carried out in this thesis consist of : firstly, comparative study of methods for producing the gum arabic powder and the impacts of DIC treatment on the properties of finished products ; secondly, optimization of the spray drying operating conditions for producing the powder mixture of gum arabic (GA) and maltodextrin (MD) as a wall material for encapsulation technology ; thirdly, comparative study of methods for producing the soybean powder and the impacts of DIC treatment on the properties of finished products ; fourthly, optimization of the spray drying operating conditions for producing the soybean powder ; and finally, impacts of ratio (GA/MD) in the manufacture of soybean powder by spray drying. The obtained results showed that the DIC technology can be used instead of the spray drying to produce the high quality powders of gum Arabic and soybean. The properties of these powders were improved and controlled by adjusting the operating conditions of spray dryer and DIC treatment. The optimal operating parameters for each case were found thanks to the process optimization in terms of product quality and heat transfer efficiency in the drying chamber.De nos jours, la nécessité d’atteindre la stabilité à long terme et la facilité d'utilisation, en plus d’une plus grande fonctionnalité, implique que de nombreux produits alimentaires et ingrédients liquides ou solides sont déshydratés ou transformés mécaniquement en poudre. Les procédés de fabrication des poudres alimentaires exigent toujours la satisfaction d’une série de critères tels que la performance du procédé et la qualité du produit. La technologie d’atomisation est toujours considérée comme la principale technologie de production des poudres dans plusieurs domaines variés grâce à ses avantages prépondérants. Néanmoins dans quelques cas, l’atomisation se montre moins efficace car les frais d’investissement initiaux et de production sont trop élevés ; le besoin d’aboutir à une grande surface spécifique des poudres entraîne beaucoup de problèmes complexes concernant le transport, le nettoyage, la récupération du produit, les risques d’explosion et la dégradation thermique du produit. Tandis que, de nombreux travaux de recherche sur le phénomène d’autovaporisation par DIC (Détente Instantanée Contrôlée) ont montré que la technologie DIC est capable de résoudre de nombreuses problématiques industrielles, menant par la suite à l’obtention de produits finis de très hautes qualités et à la réduction de la consommation d’énergie. Cependant, les applications de la technologie DIC dans la fabrication des poudres alimentaires restent encore restreintes, et la comparaison des propriétés de la poudre obtenue grâce à la DIC avec les autres méthodes de production n’est pas encore effectuée systématiquement. Dans un tel contexte, ce travail de thèse est réalisé en vue de contribuer à résoudre quelques problèmes concernant le contrôle et l’amélioration de la qualité de poudre alimentaire ainsi que l’efficacité du transfert de chaleur dans les opérations d’atomisation et d’autovaporisation (traitement DIC). Afin d’atteindre ces objectifs, deux matières premières principales examinées sont la gomme arabique et le soja. Cinq principales recherches effectuées dans cette thèse consistent en : premièrement, l’étude comparative des procédés de production de la poudre de gomme arabique et les impacts du traitement DIC sur les propriétés du produit fini ; deuxièmement, l’optimisation des conditions opératoires de l’atomiseur dans la fabrication du mélange de poudres de gomme arabique (GA) et maltodextrin (MD) en tant qu’un matériau de parois pour la technologie d’encapsulation ; troisièmement, l’étude comparative des procédés de production de la poudre de soja et les impacts du traitement DIC sur les propriétés du produit fini ; quatrièmement, l’optimisation des conditions opératoires de l’atomiseur dans la fabrication de la poudre de soja ; et finalement, les impacts du taux (GA/MD) dans la fabrication de la poudre de soja par atomisation. Les résultats obtenus ont indiqué que la technologie DIC peut être utilisée à la place de l’atomisation pour fabriquer les poudres de haute qualité de la gomme arabique et du soja. Les propriétés de ces poudres ont été contrôlées et améliorées à travers le réglage des conditions opératoires de l’atomiseur et du traitement DIC. Les paramètres opératoires optimaux dans chaque cas ont été trouvés grâce à l’optimisation de processus en termes de qualité du produit fini et d’efficacité de transfert de chaleur dans la chambre de séchage

Évaluation échographique des diamètres de la veine cave caudale, de l'aorte abdominale et de leur rapport au cours d'une anesthésie générale chez le chat sain.

Cette étude prospective vise à explorer l’utilisation de l’échographie en médecine vétérinaire comme moyen de surveillance instrumentale de la fonction cardiovasculaire par mesure des pressions artérielles et du diamètre de la veine cave caudale et de l’aorte abdominale en région iliaque chez le chat. Ces mesures ont été effectuées sur 21 chats mâles entiers en bonne santé présentés pour castration chirurgicale. Les mesures ont été effectuées sur cinq temps : vigil, après prémédication, après induction, en fin de chirurgie et à l’extubation. Les résultats montrent que la méthode est réalisable sur le chat vigil et anesthésié. Les mesures mettent en évidence une variation significative du rapport veine cave caudale/aorte en fin de chirurgie avec une tendance à la baisse majoritairement imputable à une diminution du diamètre de la veine cave caudale. Les pressions artérielles varient significativement au cours de l’anesthésie avec une augmentation après prémédication suivie d’une diminution progressive des valeurs. Le rapport veine cave caudale/aorte varie significativement en fonction de la pression artérielle diastolique en contexte anesthésique mais les pressions artérielles seules ne constituent pas un facteur de variation significatif de ce rapport. Ainsi, la mesure échographique des diamètres de la veine cave caudale et de l’aorte abdominale et la mesure oscillométrique de la pression artérielle est réalisable en décubitus sternal en région iliaque chez le chat vigil et anesthésié. Par ailleurs, le rapport veine cave caudale/aorte est influencé par l’anesthésie

Diversity of plant-parasitic nematodes on medicinal plants in Melinh station for biodiversity, Vinh Phuc Province, Vietnam

Plant-parasitic nematodes are known as one of the most important pests attacking various plants in the world, and investigating the nematode component is very essential for management of this pest and prevent damage to plants in general. Our survey of plant-parasitic nematodes on medicinal plants in Melinh Station for Biodiversity, a place for conservation of precious plants and animals in Vietnam, identified ten species that belong to nine genera, five families, and two orders of plant-parasitic nematodes parasitizing six medicinal plants. Excoecaria cochinchinensis was parasitized by the highest number of nematode genera (5 genera, including Xiphinema, Discocriconemella, Meloidogyne, Helicotylenchus, and Hemicriconemoides), while Hymenocallis littoralis was associated with the highest number of plant-parasitic nematodes (2060 nematodes/250g soil). The results also showed that Discocriconemella limitanea was found to be a dominant species with the highest number of individuals on 6 medicinal plants, and the genus Helicotylenchus had the highest frequency of appearance (5/6 plants or 83.3%). These nematodes caused symptoms such as yellowing leaves, root galls, and root lesions, which directly affect the quality and yield of medicinal plants. Based on the results, this study showed that plant-parasitic nematodes are a potential threat to the cultivation of medicinal plants in Melinh Station for Biodiversity, and thus, control measures should be applied to ensure sustainable cultivation of medicinal plants in this place