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Microbial Fermentation (microbial + fermentation)
Selected AbstractsNeural Optimization of Fed-batch Streptokinase Fermentation in a Non-ideal BioreactorTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2002Pratap R. PatnaikArticle first published online: 19 MAY 200 Abstract Microbial fermentations involving two or more kinds of competing cells and operating under realistic conditions are difficult to monitor, model and optimize by model-based methods. They deviate from ideal behavior in two significant aspects: incomplete dispersion in the broth and the influx of disturbances. The approach here has been to optimize the filtered noise and dispersion on-line through neural networks. This method has been applied to the fed-batch production of streptokinase (SK). The culture has two kinds of cells , active (or productive) and inactive , and their growth is inhibited by the substrate and the primary metabolite (lactic acid). Using simulated data, the fermentation was optimized by a system of three neural networks, updated continually during successive time intervals. Such sequential optimization with dynamic filtering of inflow noise generated better cell growth and SK activity than static optimization and even an ideal fermentation. Les fermentations microbiennes faisant intervenir deux ou plusieurs sortes de cellules en compétition et se déroulant dans des conditions réelles, sont difficiles à surveiller, à modéliser et à optimiser par des méthodes basées sur des modèles. De telles fermentations s'écartent du comportement idéal dans deux voies importantes : la dispersion incomplète dans le bouillon et la venue de perturbations. Notre approche consiste ici à optimiser le bruit filtré et la dispersion en continu par des réseaux neuronaux. Cette méthode a été appliquée à la production à alimentation discontinue de streptokinase (SK). La culture comporte deux sortes de cellules , actives (ou productives) ou inactives , et leur croissance est inhibée par le substrat et la métabolite primaire (acide lactique). À l'aide de données simulées, la fermentation a été optimisée par un système de trois réseaux neuronaux, qui ont été mis à jour continuellement à des intervalles de temps successifs. Une telle optimisation séquentielle avec filtrage dynamique du bruit génère une meilleure croissance des cellules et activité du SK que l'optimisation statique et même la fermentation idéale. [source] In vitro fermentative characteristics of ruminant diets supplemented with fibrolytic enzymes and ranges of optimal endo-,-1,4-glucanase activityJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 2 2010E. González-García Summary Effectiveness of fibrolytic enzymes supplementing a range of forage to concentrate (F:C) diets was assessed with goat (G) or cow (C) inoculum using the gas production (GP) technique. Four F:C diets were evaluated: forage (1:0), high forage (0.7:0.3), medium forage (0.5:0.5) and low forage (0.3:0.7) diets, supplemented or not with PromoteTM (PRO) at 1 or 2 ml/kg dry matter (DM). The GP kinetic was different between F:C (1:0 < 0.7:0.3 < 0.5:0.5 < 0.3:0.7) and inoculum. Responses to enzyme were positively related to forage level and differed with inoculum. The neutral detergent fibre and acid detergent fibre degradation were depressed by the concentrate in the substrates fermented with C and were not altered or even enhanced in G sets. Results confirm that increasing starch proportion modified the pattern of microbial fermentation, while no influences were detected in the improvement of cell wall degradation with fibrolytic enzymes. Another in vitro experiment was conducted to investigate factors by which endo-,-1,4-glucanase activity (EA) of PRO is compromised in a factorial design (3 × 4 × 3) for three pH (4.0, 5.5 and 6.5), four temperatures (30, 40, 50 and 70 °C) and three doses (1, 2 and 3 ml/kg DM of substrate). Maximum EA were obtained for pH 4.0, 50 °C and 3 ml/kg DM. Optimal conditions for PRO proved to be outside the normal ranges in ruminal environment. [source] Glutamate Fermentation By-product Activates Plant Defence Responses and Confers Resistance Against Pathogen InfectionJOURNAL OF PHYTOPATHOLOGY, Issue 10 2010Daisuke Igarashi Abstract In the food industry, glutamate fermentation by-product (GFB) is generated by purifying glutamate products from microbial fermentation. The potential applications of GFB for upgrading agricultural soil, for foliar fertility, and as plant plankton for shrimp have been studied. We examined the efficacy of GFB foliar application and determined that GFB treatment increased the resistance of Arabidopsis leaves to infection by bacterial pathogens. Microarray gene expression analysis of Arabidopsis leaves after treatment with GFB indicated that the expression of plant defence-related genes increased. In Corynebacterium fermentation, the active substances for induction of the defence response were extracted or solubilized after treatment with heating under acidic conditions. This extract was also effective in strawberry and grape leaves for the induction of hydrogen peroxide production. These findings suggest that foliar application of GFB that contains elicitor molecules derived from fermentation bacteria is useful for plant protection in agricultural fields. [source] The digestive tract and life history of small mammalsMAMMAL REVIEW, Issue 2 2002PETER LANGER ABSTRACT The type of food, differentiation of the large intestine and stomach, and methane production, as well as life history data, are considered in Insectivora, Rodentia and Lagomorpha. When food containing plant cell wall material is eaten, there is either a differentiation of the stomach or the large intestine. In animals with low body mass and little differentiation of the gastrointestinal tract, methane production is low, but structures essential for microbial digestion of plant cell wall material, such as haustration of the colon or formation of a caecum, can be found in many methane-producers. Animals with a body mass < 500 g and a weaning time < 20 days are non-producers of methane. Establishment of a balanced microbial population in the gastrointestinal tract requires some time. Many non-producers of methane wean their young in < 10 days, but many producers need > 50 days for the weaning process. Caviomorpha, Thryonomyidae and Hystricidae seem to have ,opened the door' to the use of low quality food by microbial fermentation, but some of them have to ,pay' for this extension of the food range by an extended weaning period, which also means an extended dependency on the mother. [source] Approaches to achieve high-level heterologous protein production in plantsPLANT BIOTECHNOLOGY JOURNAL, Issue 1 2007Stephen J. Streatfield Summary Plants offer an alternative to microbial fermentation and animal cell cultures for the production of recombinant proteins. For protein pharmaceuticals, plant systems are inherently safer than native and even recombinant animal sources. In addition, post-translational modifications, such as glycosylation, which cannot be achieved with bacterial fermentation, can be accomplished using plants. The main advantage foreseen for plant systems is reduced production costs. Plants should have a particular advantage for proteins produced in bulk, such as industrial enzymes, for which product pricing is low. In addition, edible plant tissues are well suited to the expression of vaccine antigens and pharmaceuticals for oral delivery. Three approaches have been followed to express recombinant proteins in plants: expression from the plant nuclear genome; expression from the plastid genome; and expression from plant tissues carrying recombinant plant viral sequences. The most important factor in moving plant-produced heterologous proteins from developmental research to commercial products is to ensure competitive production costs, and the best way to achieve this is to boost expression. Thus, considerable research effort has been made to increase the amount of recombinant protein produced in plants. This research includes molecular technologies to increase replication, to boost transcription, to direct transcription in tissues suited for protein accumulation, to stabilize transcripts, to optimize translation, to target proteins to subcellular locations optimal for their accumulation, and to engineer proteins to stabilize them. Other methods include plant breeding to increase transgene copy number and to utilize germplasm suited to protein accumulation. Large-scale commercialization of plant-produced recombinant proteins will require a combination of these technologies. [source] Digestion in the common marmoset (Callithrix jacchus), a gummivore,frugivoreAMERICAN JOURNAL OF PRIMATOLOGY, Issue 12 2009Michael L. Power Abstract Wild common marmosets (Callithrix jacchus) feed on fruits, insects, and gums, all of which provide different digestive challenges. Much of the ingested mass of fruits consists of seeds. In general, seeds represent indigestible bulk to marmosets and could inhibit feeding if they are not eliminated rapidly. In contrast, gums are ,-linked polysaccharides that require microbial fermentation. Their digestion would benefit from an extended residence time within the gut. Earlier research found that mean retention time (MRT) for a liquid digestive marker (cobalt EDTA) was significantly longer than MRT for a particulate marker (chromium-mordanted fiber), suggesting that common marmosets preferentially retain liquid digesta. We conducted two four-day-long digestion trials on 13 individually housed adult common marmosets fed a single-item, purified diet in order to examine the relations among MRT of cobalt EDTA and chromium-mordanted fiber, food dry matter intake (DMI), and apparent digestibility of dry matter (ADDM). We compared the MRT values with the data from the previous study mentioned above and a study using polystyrene beads. There were no significant correlations among MRT, ADDM, or DMI, although increases in DMI between trials were associated with decreases in MRT. ADDM was consistent within individuals between trials; but the mean values ranged from 75.0 to 83.4% among individuals. We found no difference in MRT between the liquid (17.5±1.6,hr) and particulate (17.9±1.4 hr) markers. Although these values were not significantly different than found previously, the MRT for chromium-mordanted fiber tended to be longer. This probably reflects the relatively small size of the chromium-mordanted fiber particles used in this study. An inverse relationship between particle size and MRT was evident; the mean MRT of polysterene beads, the largest marker, was only 8.3±1.5,hr. Marmosets appear to retain liquids and small particles within the gut longer than large particles. Am. J. Primatol. 71:957,963, 2009. © 2009 Wiley-Liss, Inc. [source] Evaluation of fermented fish-offal in the formulated diet of the freshwater catfish Heteropneustes fossilisAQUACULTURE RESEARCH, Issue 13 2008Kausik Mondal Abstract A 60-day feeding trial was conducted to test the effect of partial replacement of fishmeal by fish-offal (FO) in the diet for the freshwater catfish Heteropneustes fossilis. Three isonitrogenous (31.4% CP) diets were formulated to include a reference diet (T1) with 40% fishmeal (FM) and 0% FO and two supplementary diets: one (T2) containing 25% FM and 25% FO and another (T3) containing 20% FM and 30% FO. The FO was fermented along with mustard oil cake and rice bran before using it as an ingredient in the preparation of feed. Two separate trials were conducted with these three diets: a growth trial and a digestibility trial. H. fossilis fed the diets containing FO showed better growth and proximate composition of carcass than those fed the reference diet. Fish fed T3 diet showed maximum feed conversion, protein utilization and growth. Apparent protein digestibility (APD) was also significantly higher in the T3 diet as compared with the T1 diet. The results of the trial indicated that using microbial fermentation, FO could be included up to a 30% level as a partial (50%) replacement of fishmeal in the formulation of diet for H. fossilis. [source] Fermentative production of l -glycerol 3-phosphate utilizing a Saccharomyces cerevisiae strain with an engineered glycerol biosynthetic pathway,BIOTECHNOLOGY & BIOENGINEERING, Issue 3 2008A. Popp Abstract Interest in l -glycerol 3-phosphate (l -G3P) production via microbial fermentation is due to the compound's potential to replace the unstable substrate dihydroxyacetone phosphate (DHAP) in one-pot enzymatic carbohydrate syntheses. A Saccharomyces cerevisiae strain with deletions in both genes encoding specific l -G3Pases (GPP1 and GPP2) and multicopy overexpression of l -glycerol 3-phosphate dehydrogenase (GPD1) was studied via small-scale (100 mL) batch fermentations under quasi-anaerobic conditions. Intracellular accumulation of l -G3P reached extremely high levels (roughly 200 mM) but thereafter declined. Extracellular l -G3P was also detected and its concentration continuously increased throughout the fermentation, such that most of the total l -G3P was found outside the cells as fermentation concluded. Moreover, in spite of the complete elimination of specific l -G3Pase activity, the strain showed considerable glycerol formation suggesting unspecific dephosphorylation as a mechanism to relieve cells of intracellular l -G3P accumulation. Up-scaling the process employed fed-batch fermentation with repeated glucose feeding, plus an aerobic growth phase followed by an anaerobic product accumulation phase. This produced a final product titer of about 325 mg total l -G3P per liter of fermentation broth. Biotechnol. Bioeng. 2008;100: 497,505. © 2008 Wiley Periodicals, Inc. [source] Data reconciliation of concentration estimates from mid-infrared and dielectric spectral measurements for improved on-line monitoring of bioprocessesBIOTECHNOLOGY PROGRESS, Issue 2 2009Michal Dabros Abstract Real-time data reconciliation of concentration estimates of process analytes and biomass in microbial fermentations is investigated. A Fourier-transform mid-infrared spectrometer predicting the concentrations of process metabolites is used in parallel with a dielectric spectrometer predicting the biomass concentration during a batch fermentation of the yeast Saccharomyces cerevisiae. Calibration models developed off-line for both spectrometers suffer from poor predictive capability due to instrumental and process drifts unseen during calibration. To address this problem, the predicted metabolite and biomass concentrations, along with off-gas analysis and base addition measurements, are reconciled in real-time based on the closure of mass and elemental balances. A statistical test is used to confirm the integrity of the balances, and a non-negativity constraint is used to guide the data reconciliation algorithm toward positive concentrations. It is verified experimentally that the proposed approach reduces the standard error of prediction without the need for additional off-line analysis. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] | ||||||||||