Production Yield (production + yield)

Distribution by Scientific Domains

Selected Abstracts

The use of probiotics in shrimp aquaculture

Ali Farzanfar
Abstract Shrimp aquaculture, as well as other industries, constantly requires new techniques in order to increase production yield. Modern technologies and other sciences such as biotechnology and microbiology are important tools that could lead to a higher quality and greater quantity of products. Feeding and new practices in farming usually play an important role in aquaculture, and the addition of various additives to a balanced feed formula to achieve better growth is a common practice of many fish and shrimp feed manufacturers and farmers. Probiotics, as ,bio-friendly agents' such as lactic acid bacteria and Bacillus spp., can be introduced into the culture environment to control and compete with pathogenic bacteria as well as to promote the growth of the cultured organisms. In addition, probiotics are nonpathogenic and nontoxic microorganisms without undesirable side-effects when administered to aquatic organisms. These strains of bacteria have many other positive effects, which are described in this article. [source]


ABSTRACT A novel strain, Aspergillus sp. JN19, producing,-fructofuranosidase (FFase), was isolated from soil. According to the physiological and biochemical characteristics and its 18S rDNA gene sequence analysis, it was identified as Aspergillus japonicus. The optimal conditions for production of fructofuranosidase by A. japonicus JN-19 were investigated. The initial concentration of sucrose was 15 to 18%. Yeast extract was the best nitrogen source. K2HPO4 was effective in increasing enzyme production. The enzyme activity was increased to about 1.3 times by addition of 0.2% carboxymethylcellulose in the medium. The highest FFase activity was 55.42 U/mL at pH 5.5 and 30C, and production yield of fructooligosaccharides was 55.8%. Some characteristics of purified FFase were also studied. [source]

Substitution of plant protein for fish meal in the diet of laying ducks

ABSTRACT Fish meal is a good source of protein feed that can be used to get a high production yield even though it has a comparatively higher price. Plant protein has been found to substitute for fish meal without any adverse effect on production as well as helping to reduce feed cost. Moreover, it is not necessary for a level more than 5% fish meal in the diet of laying ducks. One type of plant protein is soybean meal, considered one of the most valuable sources of vegetable protein and whose amino acid composition is comparable to that of milk protein. In a soybean meal, the first limiting amino acid is methionine. Soybean meal can substitute for fish meal in laying ducks' diet but supplementation of methionine and lysine is recommended. Since sesame meal is rich in methionine and agrinine, 50% of soybean meal can be replaced by sesame meal without adverse effects. Leucaena leaf meal is also a valuable source of protein (26%) and carotenoids but it also has a toxic amino acid (mimosine). However, soaking leucaena leaf meal in water can remove the toxic amino acid and can be used, together with added methionine and lysine, as 10% of the diet for laying ducks. [source]

Bioreactor strategies for improving production yield and functionality of a recombinant human protein in transgenic tobacco cell cultures

Ting-Kuo Huang
Abstract Plant cell culture production of recombinant products offers a number of advantages over traditional eukaryotic expression systems, particularly if the product can be targeted to and purified from the cell culture broth. However, one of the main obstacles is product degradation by proteases that are produced during cell culture, and/or the loss of biological activity of secreted (extracellular) products as a result of alteration in the protein conformation. Because proteolysis activity and target protein stability can be significantly influenced by culture conditions, it is important to evaluate bioprocess conditions that minimize these effects. In this study, a bioreactor strategy using a protocol involving pH adjustment and medium exchange during plant cell culture is proposed for improving the production of functional recombinant ,1 -antitrypsin (rAAT), a human blood protein, produced using several alternative expression systems, including a Cauliflower mosaic virus (CaMV) 35S constitutive promoter expression system, a chemically inducible, estrogen receptor-based promoter (XVE) expression system, and a novel Cucumber mosaic virus (CMV) inducible viral amplicon (CMViva) expression system developed by our group. We have demonstrated that higher medium pH help reduce protease activity derived from cell cultures and improve the inherent stability of human AAT protein as well. This strategy resulted in a fourfold increase in the productivity of extracellular functional rAAT (100 µg/L) and a twofold increase in the ratio of functional rAAT to total rAAT (48%) in transgenic N. benthamiana cell cultures using a chemically inducible viral amplicon expression system. Biotechnol. Bioeng. 2009;102: 508,520. © 2008 Wiley Periodicals, Inc. [source]

Mutation of bacterium Vibrio gazogenes for selective preparation of colorants

Farzaneh Alihosseini
Abstract A novel marine bacterium strain effectively produced prodiginine type pigments. These colorants could dye wool, silk and synthetic fabrics such as polyester and polyacrylic and also show antibacterial properties against Escherichia coli and Staphylococcus aureus bacteria on the dyed products. Methyl nitrosoguanidine was used as a mutation agent to increase the genetic diversity and the production yield of the bacteria of the family of Vibrio gazogenes. The analysis of the mutated samples showed that two new main colorants as well as three previously found ones were produced. Liquid chromatography electro spray ionization mass spectrometry (LC-ESI-MS) and nuclear magnetic resonance (NMR) spectroscopic techniques were used to elucidate the structures of the newly produced colorants. Mass measurements revealed that the colorants C1, C2, C3, C4 have molecular masses of 321, 323, 351, and 295 Da. One unstable colorant C5 with molecular mass of 309 Da was detected as well. The mutated bacteria strains increased the yield of pigment production by about 81% and produced prodigiosin in 97% purity. The antibiotic activities of pure colorants are discussed as well. Based on their bio-activity and excellent dyeing capabilities, these colorants could be employed in cosmetic and textile industries. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source]

Reassessing culture media and critical metabolites that affect adenovirus production

Chun Fang Shen
Abstract Adenovirus production is currently operated at low cell density because infection at high cell densities still results in reduced cell-specific productivity. To better understand nutrient limitation and inhibitory metabolites causing the reduction of specific yields at high cell densities, adenovirus production in HEK 293 cultures using NSFM 13 and CD 293 media were evaluated. For cultures using NSFM 13 medium, the cell-specific productivity decreased from 3,400 to 150 vp/cell (or 96% reduction) when the cell density at infection was increased from 1 to 3 × 106 cells/mL. In comparison, only 50% of reduction in the cell-specific productivity was observed under the same conditions for cultures using CD 293 medium. The effect of medium osmolality was found critical on viral production. Media were adjusted to an optimal osmolality of 290 mOsm/kg to facilitate comparison. Amino acids were not critical limiting factors. Potential limiting nutrients including vitamins, energy metabolites, bases and nucleotides, or inhibitory metabolites (lactate and ammonia) were supplemented to infected cultures to further investigate their effect on the adenovirus production. Accumulation of lactate and ammonia in a culture infected at 3 × 106 cells/mL contributed to about 20% reduction of the adenovirus production yield, whereas nutrient limitation appeared primarily responsible for the decline in the viral production when NSFM 13 medium was used. Overall, the results indicate that multiple factors contribute to limiting the specific production yield at cell densities beyond 1 × 106 cells/mL and underline the need to further investigate and develop media for better adenoviral vector productions. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source]

Effects of citraconylation on enzymatic modification of human proinsulin using trypsin and carboxypeptidase B

Young-Jin Son
Abstract Insulin is a polypeptide hormone which is produced by the ,-cell of pancreas and controls the blood glucose level in the human body. Enzymatic modification of human proinsulin using trypsin and carboxypeptidase B generally causes high accumulation of insulin derivatives, leading to more complicated purification processes. A simple method including citraconylation and decitraconylation in the enzymatic modification process was developed for the reduction of a major derivative, des-threonine human insulin. Addition of 3.0 g citraconic anhydride per g protein into the reaction solution led to the citraconylation of lysine residues in human proinsulin and reduction of relative des-threonine insulin content from 13.5 to 1.0%. After the enzymatic hydrolysis of the citraconylated proinsulin, 100% of lysine residues can be decitraconylated and restored by adjusting pH to 2,3 at 25 °C. Combination of hydrogen peroxide addition and citraconylation of proinsulin expressed in recombinant Escherichia coli remarkably improved the conversion yield of insulin from 52.7 to 77.7%. Consequently, citraconylation of lysine residues blocked the unexpected cleavage of human proinsulin by trypsin, minimized the formation of des-threonine insulin and hence increased the production yield of active insulin. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source]

Very High Yield Growth of Vertically Aligned Single-Walled Carbon Nanotubes by Point-Arc Microwave Plasma CVD,

F. Zhong
A very high yield, selective growth of dense, vertically aligned single-walled carbon nanotubes (SWNTs) has been demonstrated for the first time on Si substrates with a sandwich-like coating structure of Al2O3/Fe/Al2O3 at a low (600,°C) temperature by point-arc microwave plasma CVD. The SWNT film thickness increases continuously with the growth time, suggesting an almost unlimited life time for the catalyst. A film thickness of 420,,m, and production yield of SWNTs to catalyst of about 770,000,% can be achieved within 2,h. [source]

Detailed determination of smoke gas contents using a small-scale controlled equivalence ratio tube furnace method

Per Blomqvist
Abstract A series of tests including seven different materials and products have been conducted using a controlled equivalence ratio tube furnace test method. The main objective of the tests was to determine yields of fire-generated products at defined combustion conditions. The tube furnace test method was set up and run in close agreement with that described in BS 7990:2003. At the time of experimental work the new tube furnace method was in the process of becoming an international standard. It was thus of interest to make an assessment of the capability of the method for determining production yields of important toxic fire products from different types of materials and products. The test series included solid wood, flexible polyurethane (PUR), fire-retarded rigid PUR, a polyvinyl chloride (PVC) carpet, a high-performance data cable with fluorine-containing polymer matrix, a PVC-based cable sheathing material and fire-retarded polyethylene cable insulation material. Duplicate tests were generally conducted at both well-ventilated and vitiated combustion conditions with these materials. The smoke gases produced from the combustion were quantified for inorganic gases by FTIR technique in all tests. A more detailed analysis of the smoke gases was conducted for some of the materials. This extended analysis contained a detailed assessment of organic compounds including, e.g. volatile organic compounds, isocyanates, aldehydes and polycyclic aromatic hydrocarbons. The analysis further included measurement of the size distribution of fire-generated particles for some of the materials. The quantification of toxic inorganic gases produced by combustion at both well-ventilated and vitiated conditions was successful regarding repeatability and stability. Typical yields for the two fire stages investigated were determined for a wide range of materials and products. The detailed analysis of organic compounds further corroborated that the new tube furnace method can replicate defined combustion conditions. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Computations on three isomers of La@C74

k Slanina
Abstract Density-functional theory calculations are presented for La@C74, where C74 is either the IPR (isolated pentagon rule) cage or two cages with a pentagon-pentagon junction. Their relative thermodynamic production yields are evaluated using the calculated terms, and it is shown that the IPR-based endohedral prevails at relevant temperatures in agreement with the observation. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source]

Improvement of Yarrowia lipolytica lipase production by fed-batch fermentation

Patrick Fickers
Abstract Two different types of fed-batch fermentation were investigated to improve production yields of the Lip2 extracellular lipase in Y. lipolytica mutant-strain LgX64.81 grown in a 20l bioreactor. Compare to batch cultures, culture feeding with the complete medium led to a 2-fold increased lipase production (2016 ± 76 U ml,1) whereas addition of a combination of glucose and olive oil led to a 3-fold increase. The high level of lipase production obtained on glucose media with Y. lipolytica LgX64.81 could be related to its phenotype i.e. a lower sensibility to glucose catabolite repression due to a modification in the level of HXK1 expression. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

US,Mexico fresh vegetable trade: the effects of trade liberalization and economic growth

Jaime E. Málaga
NAFTA; Vegetables; Trade liberalization; Mexico Abstract Studies of US-Mexico vegetable trade have generally emphasized the importance of US tariffs in determining the competitive advantage of US producers. Even so, research has identified at least four factors related primarily to the different levels of economic development in the US and Mexico that also have important effects on US-Mexico agricultural trade in general and fresh vegetable trade in particular. These include the differential growth rates of US and Mexican real wages, production technology (yields), and per capita income as well as cyclical movements in the real Mexican Peso/US Dollar exchange rate. This study examines the relative contribution of NAFTA and the development-related factors to likely future changes in US fresh vegetable imports from Mexico. The analysis employs an econometric simulation model of US and Mexican markets for five fresh vegetables (tomatoes, cucumbers, squash, bell peppers, and onions) accounting for 80% of US fresh vegetable imports. The results suggest that the 1994,1995 Peso devaluation rather than NAFTA was primarily responsible for the sharp increase in US imports of Mexican vegetables observed in the first years following the implementation of NAFTA. Over time, however, the results suggest that differences in the growth rates of US and Mexican production yields and, to a lesser extent, of US and Mexican real incomes and/or real wage rates could plausibly contribute more to the future growth of US tomato, squash, and onion imports from Mexico than the trade liberalizing effects of NAFTA. [source]

Effect of agitation intensity on the exo-biopolymer production and mycelial morphology in Cordyceps militaris

J.P. Park
Aims:,The influence of agitation intensity on Cordyceps militaris morphology and exo-biopolymer production was investigated in a 5 litre stirred vessel using a six-blade Rushton turbine impeller. Methods and Results:,The mycelial morphology of C. militaris was characterized by means of image analysis, which included mean diameter, circularity, roughness and compactness of the pellets. The morphological parameters of the pellets grown under different stirring conditions were significantly different, which correspondingly altered exo-biopolymer production yields. Conclusions:,The compactness of the pellets was found to be the most critical parameter affecting exo-biopolymer biosynthesis; more compact pellets were formed at 150 rev min,1 with maximum exo-biopolymer production (15 g l,1). Significance and Impact of the Study:,The results of this study suggest that morphological change of pellets is a good indicator for identifying the cell activity for exo-biopolymer production. [source]

CPCR1, but not its interacting transcription factor AcFKH1, controls fungal arthrospore formation in Acremonium chrysogenum

Birgit Hoff
Summary Fungal morphogenesis and secondary metabolism are frequently associated; however, the molecular determinants connecting both processes remain largely undefined. Here we demonstrate that CPCR1 (cephalosporin C regulator 1 from Acremonium chrysogenum), a member of the winged helix/regulator factor X (RFX) transcription factor family that regulates cephalosporin C biosynthesis, also controls morphological development in the ,-lactam producer A. chrysogenum. The use of a disruption strain, multicopy strains as well as several recombinant control strains revealed that CPCR1 is required for hyphal fragmentation, and thus the formation of arthrospores. In a ,cpcR1 disruption strain that exhibits only hyphal growth, the wild-type cpcR1 gene was able to restore arthrospore formation; a phenomenon not observed for ,cpcR1 derivatives or non-related genes. The intracellular expression of cpcR1, and control genes (pcbC, egfp) was determined by in vivo monitoring of fluorescent protein fusions. Further, the role of the forkhead transcription factor AcFKH1, which directly interacts with CPCR1, was studied by generating an Acfkh1 knockout strain. In contrast to CPCR1, AcFKH1 is not directly involved in the fragmentation of hyphae. Instead, the presence of AcFKH1 seems to be necessary for CPCR1 function in A. chrysogenum morphogenesis, as overexpression of a functional cpcR1 gene in a ,Acfkh1 background has no effect on arthrospore formation. Moreover, strains lacking Acfkh1 exhibit defects in cell separation, indicating an involvement of the forkhead transcription factor in mycelial growth of A. chrysogenum. Our data offer the potential to control fungal growth in biotechnical processes that require defined morphological stages for optimal production yields. [source]

Precursor Balancing for Metabolic Engineering of Lycopene Production in Escherichia coli

William R. Farmer
One issue that must be addressed in the rational design of metabolic pathways is the elimination of potential bottlenecks in the upstream pathways. We have reconstructed the isoprenoid pathway to overproduce the carotenoid lycopene in Escherichia coli. Here we show that the distribution between pyruvate and glyceraldehyde 3-phosphate (G3P), the originating precursors of the isoprenoid pathway, is a major factor that can limit isoprenoid production yields in E. coli. In particular, alterations in the central metabolism that redirect flux from pyruvate back to G3P enhance lycopene production, while alterations that channel carbon flux away from the G3P pool have the opposite effect. These results suggest that G3P may be limiting in the biosynthesis of lycopene, and modifications that achieve a more equitable distribution between the two precursors are able to increase the lycopene yield in metabolically engineered E. coli. [source]

Large-Scale In Vivo Synthesis of the Carbohydrate Moieties of Gangliosides GM1 and GM2 by Metabolically Engineered Escherichia coli

CHEMBIOCHEM, Issue 5 2003
Tatiana Antoine
Abstract Two metabolically engineered Escherichia coli strains have been constructed to produce the carbohydrate moieties of gangliosides GM2 (GalNAc, -4(NeuAc, -3)Gal, -4Glc; Gal=galactose, Glc=glucose, Ac=acetyl) and GM1 (Gal, -3GalNAc, -4(NeuAc, -3)Gal, -4Glc. The GM2 oligosaccharide-producing strain TA02 was devoid of both , -galactosidase and sialic acid aldolase activities and overexpressed the genes for CMP-NeuAc synthase (CMP=cytidine monophosphate), , -2,3-sialyltransferase, UDP-GlcNAc (UDP=uridine diphosphate) C4 epimerase, and , -1,4-GalNAc transferase. When this strain was cultivated on glycerol, exogenously added lactose and sialic acid were shown to be actively internalized into the cytoplasm and converted into GM2 oligosaccharide. The in vivo synthesis of GM1 oligosaccharide was achieved by taking a similar approach but using strain TA05, which additionally overexpressed the gene for , -1,3-galactosyltransferase. In high-cell-density cultures, the production yields for the GM2 and GM1 oligosaccharides were 1.25 g,L,1and 0.89 g,L,1, respectively. [source]