Home About us Contact
|
Home About us Contact | ||
|
|
||
Efficient Production (efficient + production)
Selected AbstractsEfficient Production of the Liquid Fuel 2,5-Dimethylfuran from Fructose Using Formic Acid as a Reagent,ANGEWANDTE CHEMIE, Issue 37 2010Todsapon Thananatthanachon Dr. Drei in einem: Für die Erzeugung flüssiger Kraftstoffe aus Biomasse werden neue, vielseitige Reagentien benötigt. Ein Beispiel hierfür ist Ameisensäure, die bei der Umsetzung von Fructose in die Titelverbindung 1 drei Funktionen erfüllt: Sie vermittelt die Isomerisierung-Dehydratisierung, dient als H2 -Quelle für die Hydrierung und unterstützt die Desoxygenierung von Alkoholfunktionalitäten. [source] Utilization of an Alternative Carbon Source for Efficient Production of Human ,1 -Antitrypsin by Genetically Engineered Rice Cell CultureBIOTECHNOLOGY PROGRESS, Issue 3 2001Masaaki Terashima Human ,1 -antitrypsin was produced by genetically engineered rice cells using promoter and signal peptide of a rice ,-amylase isozyme. Batch and continuous cultures were employed to investigate the effects of alternative carbon sources on the ,1 -antitrypsin production. While this expression system is inducible by sugar depletion, we have found that the productivity of ,1 -antitrypsin increased 2.4- to 3.4-fold, compared with the control medium without carbon source, in medium containing an alternative carbon source, such as pyruvic acid and glyoxylic acid. The accumulated ,1 -antitrypsin in the medium containing pyruvic acid reached 18.2,24.2 mg/g-dry cell in 50,70 h by batch culture. [source] Efficient production of monoclonal antibodies recognizing specific structures in Caenorhabditis elegans embryos using an antigen subtraction methodGENES TO CELLS, Issue 7 2008Kazumasa Takeda Monoclonal antibodies (mAbs) have been widely used to probe molecular components of specific cell types or cellular structures. We have developed a method to enrich antigens of low abundance in heterogeneous molecule mixtures by subtracting abundant antigens. The subtracted immunogen mixture is then used for immunization, which significantly increases the production of mAbs that exhibit specific staining patterns. By applying this "antigen subtraction" method to the embryonic extract of Caenorhabditis elegans, we have successfully isolated 35 mAbs that recognize specific structures, including P granules, muscles, the pharynx, and subsets of hypodermal cells; some of the mAbs revealed previously unreported cellular structures. This antigen subtraction approach can be used in various applications to produce mAbs against relatively scarce antigens in complex molecular mixtures. The mAbs will be useful tools for developmental and cell biological studies. [source] Safety and efficacy of vaccinesDERMATOLOGIC THERAPY, Issue 2 2009Brenda L. Bartlett ABSTRACT For the past two centuries, vaccines have provided a safe and effective means of preventing a number of infectious diseases. Although the safety of some vaccines has been questioned in recent years, the currently available vaccines are more than a millionfold safer than the diseases they are designed to prevent. Vaccines, however, should always be used in conjunction with other public health interventions. One important intervention is education because the general public can be led to believe that vaccines are unsafe and not needed by misinformation readily available electronically and in print. Not only are some vaccines available via injection but other vaccines are also given orally or intranasally. New vaccines are being studied for topical and intravaginal use. In addition, new systems are being developed for more efficient production of vaccines, especially for influenza. Vaccines are currently available for only a limited number of viral and bacterial diseases. In the future, it is anticipated that safe and effective vaccines will be developed against a number of other viral and bacterial infections as well as fungal and protozoan diseases. [source] Enhancement of the NAD(P)(H) Pool in Saccharomyces cerevisiaeENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 4 2008A. Knepper Abstract Asymmetric biosyntheses allow for an efficient production of chiral building blocks. The application of whole cells as biocatalysts for asymmetric syntheses is advantageous because they already contain the essential coenzymes NAD(H) or NADP(H), which additionally can be regenerated in the cells. Unfortunately, reduced catalytic activity compared to the oxidoreductase activity is observed in many cases during whole-cell biotransformation. This may be caused by low intracellular coenzyme pool sizes and/or a decline in intracellular coenzyme concentrations. To enhance the intracellular coenzyme pool sizes, the effects of the precursor metabolites adenine and nicotinic acid on the intracellular accumulation of NAD(H) and NADP(H) were studied in Saccharomyces cerevisiae. Based on the results of simple batch experiments with different precursor additions, fed-batch processes for the production of yeast cells with enhanced NAD(H) or enhanced NADP(H) pool sizes were developed. Supplementation of the feed medium with 95,mM adenine and 9.5,mM nicotinic acid resulted in an increase of the intracellular NAD(H) concentration by a factor of 10 at the end of the fed-batch process compared to the reference process. The final NAD(H) concentration remains unchanged if the feed medium was solely supplemented with 95,mM adenine, but intracellular NADP(H) was increased by a factor of 4. The effects of NADP(H) pool sizes on the asymmetric reduction of ethyl-4-chloro acetoacetate (CAAE) to the corresponding (S)-4-chloro-3-hydroxybutanoate (S-CHBE) was evaluated with S.,cerevisiae,FasB,His6 as an example. An intracellular threshold concentration above 0.07,mM NADP(H) was sufficient to increase the biocatalytic S-CHBE productivity by 25,% compared to lower intracellular NADP(H) concentrations. [source] Evaluation of detergents for the soluble expression of ,-helical and ,-barrel-type integral membrane proteins by a preparative scale individual cell-free expression systemFEBS JOURNAL, Issue 23 2005Christian Klammt Cell-free expression has become a highly promising tool for the fast and efficient production of integral membrane proteins. The proteins can be produced as precipitates that solubilize in mild detergents usually without any prior denaturation sttif. Alternatively, membrane proteins can be synthesized in a soluble form by adding detergents to the cell-free system. However, the effects of a representative variety of detergents on the production, solubility and activity of a wider range of membrane proteins upon cell-free expression are currently unknown. We therefore analyzed the cell-free expression of three structurally very different membrane proteins, namely the bacterial ,-helical multidrug transporter, EmrE, the ,-barrel nucleoside transporter, Tsx, and the porcine vasopressin receptor of the eukaryotic superfamily of G-protein coupled receptors. All three membrane proteins could be produced in amounts of several mg per one ml of reaction mixture. In general, the detergent 1-myristoyl-2-hydroxy- sn -glycero-3-[phospho- rac -(1-glycerol)] was found to be most effective for the resolubilization of membrane protein precipitates, while long chain polyoxyethylene-alkyl-ethers proved to be most suitable for the soluble expression of all three types of membrane proteins. The yield of soluble expressed membrane protein remained relatively stable above a certain threshold concentration of the detergents. We report, for the first time, the high-level cell-free expression of a ,-barrel type membrane protein in a functional form. Structural and functional variations of the analyzed membrane proteins are evident that correspond with the mode of expression and that depend on the supplied detergent. [source] Hepatitis B and C virus coinfection: A novel model system reveals the absence of direct viral interference,HEPATOLOGY, Issue 1 2009Pantxika Bellecave Coinfection with hepatitis B virus (HBV) and hepatitis C virus (HCV) has been associated with severe liver disease and frequent progression to cirrhosis and hepatocellular carcinoma. Clinical evidence suggests reciprocal replicative suppression of the two viruses, or viral interference. However, interactions between HBV and HCV have been difficult to study due to the lack of appropriate model systems. We have established a novel model system to investigate interactions between HBV and HCV. Stable Huh-7 cell lines inducibly replicating HBV were transfected with selectable HCV replicons or infected with cell culture,derived HCV. In this system, both viruses were found to replicate in the same cell without overt interference. Specific inhibition of one virus did not affect the replication and gene expression of the other. Furthermore, cells harboring replicating HBV could be infected with cell culture,derived HCV, arguing against superinfection exclusion. Finally, cells harboring replicating HBV supported efficient production of infectious HCV. Conclusion: HBV and HCV can replicate in the same cell without evidence for direct interference in vitro. Therefore, the viral interference observed in coinfected patients is probably due to indirect mechanisms mediated by innate and/or adaptive host immune responses. These findings provide new insights into the pathogenesis of HBV,HCV coinfection and may contribute to its clinical management in the future. (HEPATOLOGY 2009.) [source] Production of polyhydroxyalkanoates: the future green materials of choiceJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2010Everest Akaraonye Abstract Polyhydroxyalkanoates (PHAs) have recently been the focus of attention as a biodegradable and biocompatible substitute for conventional non degradable plastics. The cost of large-scale production of these polymers has inhibited its widespread use. Thus, economical, large-scale production of PHAs is currently being studied intensively. Various bacterial strains, either wild-type or recombinant have been utilized with a wide spectrum of utilizable carbon sources. New fermentation strategies have been developed for the efficient production of PHAs at high concentration and productivity. With the current advances, PHAs can now be produced to a concentration of 80 g L,1 with productivities greater than 4 g PHA L,1 h,1. These advances will further lower the production cost of PHAs and allow this family of polymers to become a leading biodegradable polymer in the near future. This review describes the properties of PHAs, their uses, the various attempts towards the production of PHAs, focusing on the utilization of cheap substrates and the development of different fermentation strategies for the production of these polymers, an essential step forward towards their widespread use. Copyright © 2010 Society of Chemical Industry [source] The fermentation of mixtures of D -glucose and D -xylose by Candida shehatae, Pichia stipitis or Pachysolen tannophilus to produce ethanolJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2002Sebastián Sánchez Abstract The fermentation of mixtures of D -glucose and D -xylose by three non-traditional yeasts: Candida shehatae (ATCC 34887), Pachysolen tannophilus (ATCC 32691) and Pichia stipitis (ATCC 58376) have been studied to determine the optimal strain and initial culture conditions for the efficient production of ethanol. The comparison was made on the basis of maximum specific growth rate (µm), biomass productivity, the specific rates of total substrate consumption (qs) and ethanol production (qE) and the overall yields of ethanol and xylitol. All the experiments were performed in stirred-tank batch reactors at a temperature of 30,°C. The initial pH of the culture medium was 4.5. The highest values of µm (above 0.5,h,1) were obtained with P stipitis in cultures containing high concentrations of D -xylose. All three yeasts consumed the two monosaccharides in sequence, beginning with D -glucose. The values of qs diminished during the course of each experiment with all of the yeasts. The highest values of the specific rates of total substrate consumption and ethanol production were obtained with C shehatae (for t,=,10,h, qs and qE were above 5,g,g,1,h,1 and 2,g,g,1,h,1, respectively), although the highest overall ethanol yields were fairly similar with all three yeasts, at around 0.4,g,g,1. © 2002 Society of Chemical Industry [source] Deletion of N-terminus of human tyrosine hydroxylase type 1 enhances stability of the enzyme in AtT-20 cellsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 1 2005Akira Nakashima Abstract Wildtype human tyrosine hydroxylase (TH) type 1 and 4 mutants (del-52, a form with the first 52 amino acid residues deleted; del-157, one with the first 157 amino acid residues deleted; RR-EE, one in which Arg37 -Arg38 was replaced by Glu37 -Glu38; and S40D, one in which Ser40 was replaced by Asp40) were expressed in AtT-20 mouse neuroendocrine cells in order to clarify how deeply the N-terminus of TH is involved in the efficient production of dopamine (DA) in mammalian cells. The amounts of DA that accumulated in AtT-20 cells expressing these human TH type 1 (hTH1) phenotypes were in the following order: del-52 = del-157 = RR-EE > S40D > wildtype, although the enzyme activities of del-52 and del-157 were lower than those of wildtype, RR-EE, and S40D. The observation on immunoblot analyses that the N-terminus-deleted hTH1 mutants were much more stable than wildtype can reconcile the discrepant results. Computer-assisted analysis of the spatial configuration of hTH1 identified five newly recognized PEST motifs, one of which was located in the N-terminus sequence of Met1 -Lys12 and predicted that deletion of the N-terminus region would alter the secondary structure within the catalytic domain. Collectively, the high stability of the N-terminus-deleted hTH1 mutants can be generated by the loss of a PEST motif in their N-termini and the structural change in the catalytic domain, which would promise an efficient production of DA in mammalian cells expressing N-terminus deleted hTH1. © 2005 Wiley-Liss, Inc. [source] Emulsion polymerization: From fundamental mechanisms to process developmentsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2004José M. Asua Abstract Emulsion polymers are "products by process" whose main properties are determined during polymerization. In this scenario of margins reduction, increasing competition, and public sensitivity to environmental issues, the challenge is to achieve an efficient production of high-quality materials in a consistent, safe, and environmentally friendly way. This highlight reviews the investigations carried out at The University of the Basque Country to develop a knowledge-based strategy to achieve these goals. First, the research in fundamental mechanisms is discussed. This includes studies in radical entry and exit, oil-soluble initiators, propagation-rate constants of acrylic monomers, processes involved in the formation of branched and crosslinked polymers, microstructure modification by postreaction operations, the formation of particle morphology, and reactive surfactants. The advanced mathematical models developed in the group are also reviewed. In the second part, the advances in process development (optimization, online monitoring and control, monomer removal, production of high-solids, low-viscosity latices, and process intensification) are presented. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1025,1041, 2004 [source] CO2 Laser , Workhorse for Industrial ManufacturingLASER TECHNIK JOURNAL, Issue 3 2009Flexible, reliable, well proven tool for a large variety of laser processing systems For more than 30 years lasers are used for industrial production with high success. Modern efficient production would not be imaginable without lasers and laser processes. Since the beginning days CO2 lasers were dominating the market of continuous cutting and welding applications (referred here as "Macro" applications) because of their high power and electrical efficiency, reliability and cost efficiency. [source] Improvement for the production of clavulanic acid by mutant Streptomyces clavuligerusLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2002S.D. Lee Aims:,To improve the production of clavulanic acid through the development of strains, the selection of a production medium and a pH shift strategy in a bioreactor. Methods and Results:,Streptomyces clavuligerus mutant 15 was selected by antibacterial activities. As a result of pH control in a 2·5 l bioreactor, the highest productivity (3·37 ,g ml,1 h,1) was obtained at a controlled pH of 7·0. Conclusions:,The highest level of production obtained was an increase of about 36% compared with a non-controlled pH. When the production of clavulanic acid reached the maximum level, the pH was shifted from 7·0 to 6·0 for reduction in decomposition rate. The maximum concentration of clavulanic acid was maintained for 24 h as a result of the pH shift control, and a significant reduction in the decomposition of clavulanic acid was obtained. Significance and Impact of the Study:,Clavulanic acid decomposition was considerably reduced as a result of the pH shift control. The results of this study can be applied for the efficient production of ,-lactamase inhibitory antibiotics. [source] pFARs, Plasmids free of antibiotic resistance markers, display high-level transgene expression in muscle, skin and tumour cellsTHE JOURNAL OF GENE MEDICINE, Issue 4 2010Corinne Marie Abstract Background Nonviral gene therapy requires a high yield and a low cost production of eukaryotic expression vectors that meet defined criteria such as biosafety and quality of pharmaceutical grade. To fulfil these objectives, we designed a novel antibiotic-free selection system. Methods The proposed strategy relies on the suppression of a chromosomal amber mutation by a plasmid-borne function. We first introduced a nonsense mutation into the essential Escherichia coli thyA gene, resulting in thymidine auxotrophy. The bacterial strain was optimized for the production of small and novel plasmids free of antibiotic resistance markers (pFARs) and encoding an amber suppressor t-RNA. Finally, the potentiality of pFARs as eukaryotic expression vectors was assessed by monitoring luciferase activities after electrotransfer of LUC-encoding plasmids into various tissues. Results The introduction of pFARs into the optimized bacterial strain restored normal growth to the auxotrophic mutant and allowed an efficient production of monomeric supercoiled plasmids. The electrotransfer of LUC-encoding pFAR into muscle led to high luciferase activities, demonstrating an efficient gene delivery. In transplanted tumours, transgene expression levels were superior after electrotransfer of the pFAR derivative compared to a plasmid carrying a kanamycin resistance gene. Finally, in skin, whereas luciferase activities decreased within 3 weeks after intradermal electrotransfer of a conventional expression vector, sustained luciferase expression was observed with the pFAR plasmid. Conclusions Thus, we have designed a novel strategy for the efficient production of biosafe plasmids and demonstrated their potentiality for nonviral gene delivery and high-level transgene expression in several tissues. Copyright © 2010 John Wiley & Sons, Ltd. [source] Reformer and membrane modules plant to optimize natural gas conversion to hydrogenASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2009M. De Falco Abstract Membrane technology may play a crucial role in the efficient production of hydrogen from natural gas and heavy hydrocarbons. The present work assesses the performance of a hydrogen production plant utilizing by reformer and membrane modules (RMM), by which the hydrogen produced in reaction units is separated by Pd-based membranes. A major advantage of RMM architecture is the shift of chemical equilibria favoring hydrogen production due to the removal of hydrogen through membranes at each reaction step, thus improving hydrogen yield while simultaneously allowing methane conversion at temperatures below 650 °C. Lower operating temperatures allow location of the modules downstream of a gas turbine, achieving an efficient hybrid system producing electric power and hydrogen with a significant reduction in energy consumption of approximately 10% relative to conventional systems. Fundamental concepts are analyzed and integrated into a process scheme. Effects of variables including reactor temperature outlet, steam-to-carbon ratio and recycle ratio throughout pinch and sensitivity analysis are described. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] The integration of green chemistry into future biorefineriesBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 1 2009James H. Clark Abstract The use of biorefineries for the production of chemicals as well as materials and energy products is key to ensuring a sustainable future for the chemical and allied industries. Through the integration of green chemistry into biorefineries, and the use of low environmental impact technologies, we can establish future supply chains for genuinely green and sustainable chemical products. The first step in these future biorefineries should be the benign extraction of surface chemicals; here the use of greener solvents, such as supercritical carbon dioxide and bioethanol, should be considered. The residues will often be rich in lignocellulosics and the effective separation of the cellulose is a major challenge which may, in the future, be assisted by greener solvents, such as ionic liquids. Lignin is nature's major source of aromatics; we need new ways to produce small aromatic building blocks from lignin in order to satisfy the enormous and diverse industrial demand for aromatics. Fermentation can be used to convert biomass into a wide range of bioplatform chemicals in addition to ethanol. Their green chemical conversion to higher value chemicals is as important as their efficient production; here clean technologies such as catalysis , notably biocatalysis and heterogeneous catalysis , the use of benign solvents, and energy efficient reactors are essential. Thermochemical processes for the conversion of biomass, such as the production of pyrolysis oil, will also play an important role in future biorefineries and here again green chemistry methods should be used to go to higher value downstream chemicals. Published in 2008 by John Wiley & Sons, Ltd [source] Purification, crystallization and preliminary X-ray crystallographic analysis of xylose reductase from Candida tropicalisACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2009Li-Chun Chen Xylose reductase (XR), which requires NADPH as a co-substrate, catalyzes the reduction of d -xylose to xylitol, which is the first step in the metabolism of d -xylose. The detailed three-dimensional structure of XR will provide a better understanding of the biological significance of XR in the efficient production of xylitol from biomass. XR of molecular mass 36.6,kDa from Candida tropicalis was crystallized using the hanging-drop vapour-diffusion method. According to X-ray diffraction data from C. tropicalis XR crystals at 2.91,Å resolution, the unit cell belongs to space group P31 or P32. Preliminary analysis indicated the presence of four XR molecules in the asymmetric unit, with 68.0% solvent content. [source] Highly efficient strategy for enhancing taxoid production by repeated elicitation with a newly synthesized jasmonate in fed-batch cultivation of Taxus chinensis cellsBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2005Zhi-Gang Qian Abstract A highly efficient bioprocessing strategy was developed for enhancing the production of plant secondary metabolites by repeatedly eliciting a fed-batch culture with a newly synthesized powerful jasmonate analog, 2,3-dihydroxypropyl jasmonate (DHPJA). In suspension cultures of a high taxuyunnanine C (Tc)-producing cell line of Taxus chinensis, 100 ,M DHPJA was added on day 7 to fed-batch cultures with feeding of 20 g L,1 sucrose on the same day. The synergistic effect of elicitation and substrate feeding on Tc biosynthesis was observed, which resulted in higher Tc accumulation than that by elicitation or sucrose feeding alone. More interestingly, both specific Tc yield (i.e., Tc content) and volumetric yield was further improved by a second addition of 100 ,M DHPJA (on day 12) to the fed-batch cultures. In particular, with repeated elicitation and sucrose feeding the Tc volumetric yield was increased to 827 ± 29 mg L,1, which was 5.4-fold higher than that of the nonelicited batch culture. Furthermore, the above novel strategy was successfully applied from shake flask to a 1-L airlift bioreactor. A high Tc production and productivity of 738 ± 41 mg L,1 and 33.2 ± 1.9 mg L,1 d,1, respectively, was achieved, which is higher than previous reports on Tc production in bioreactors. The results suggest that the aforementioned bioprocessing strategy may potentially be applied to other cell culture systems for efficient production of plant secondary metabolites. © 2005 Wiley Periodicals, Inc. [source] Enhanced interferon-, production by CHO cells through elevated osmolality and reduced culture temperatureBIOTECHNOLOGY PROGRESS, Issue 5 2009Young Kue Han Abstract For efficient production of native interferon-, (IFN-,) in recombinant CHO cell culture, the IFN-, molecular aggregation that occurs during culture needs to be minimized. To do so, we investigated the effect of hyperosmolality and hypothermia on IFN-, production and molecular aggregation in rCHO cell culture. Both hyperosmolality (470 mOsm/kg) and hypothermia (32°C) increased specific native INF-, productivity qIFN-,. Furthermore, they decreased the IFN-, molecular aggregation, although severe IFN-, molecular aggregation could not be avoided in the later phase of culture. To overcome growth suppression at hyperosmolality and hypothermia, cells were cultivated in a biphasic mode. Cells were first cultivated at 310 mOsm/kg and 37°C for 2 days to rapidly obtain a reasonably high cell concentration. The temperature and osmolality were then shifted to 32°C and 470 mOsm/kg, respectively, to achieve high qIFN-, and reduced IFN-, molecular aggregation. Due to the enhanced qIFN-, and delayed molecular aggregation, the highest native IFN-, concentration achieved on day 6 was 18.03 ± 0.61 mg/L, which was 5.30,fold higher than that in a control batch culture (310 mOsm/kg and 37°C). Taken together, a combination of hyperosmolality and hypothermia in a biphasic culture is a useful strategy for improved native IFN-, production from rCHO cells. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] A novel three-stage light irradiation strategy in the submerged fermentation of medicinal Mushroom Ganoderma lucidum for the efficient production of ganoderic acid and Ganoderma polysaccharidesBIOTECHNOLOGY PROGRESS, Issue 6 2008Wei Zhang Abstract A novel three-stage light irradiation strategy in the submerged fermentation of medicinal mushroom Ganoderma lucidum for the efficient production of bioactive metabolites ganoderic acid (GA) and Ganoderma polysaccharides was developed. Significance of light quality, i.e., blue light (390,500 nm, ,max = 470 nm), red light (560,700 nm, ,max = 625 nm), and white light (400,740 nm, ,max = 550 nm), was studied at first. Interestingly, there was a gradual decrease trend of GA content after the culture of day 2 when the maximal GA content was obtained, while GA content decreased slowly under white light irradiation after day 6. The dark environment was favorable to the specific GA biosynthesis (i.e., GA content) before day 6, and after that the optimum was white light irradiation. A relatively lower irradiation density of white light (i.e., 0.94 and 2.82 W/m2) was beneficial for the specific GA biosynthesis before day 6, while GA content was higher under higher irradiation density of white light (i.e., 4.70 and 9.40 W/m2) at the later-stage of cultivation. 4.70 W/m2 white light irradiation culture was the best from the viewpoint of GA accumulation. Therefore, a two-stage light irradiation strategy by combing the first 2 days dark culture with the following 4.70 W/m2 white light irradiation culture was developed. The highest GA production in the two-stage culture was 276.0 ± 12.5 mg/L, which was increased by 19% compared to 4.70 W/m2 white light irradiation culture (i.e., 232.4 ± 15.8 mg/L) and by 178% compared to the dark culture (i.e., 99.4 ± 1.0 mg/L). Although there still existed a gradual decrease trend of GA content after day 2 when the maximal GA content was obtained in the two-stage culture. Following three-stage light irradiation strategy was further demonstrated in order to turn around the sharp decrease of GA content after day 2. The first-stage was the 2-day dark culture; the second-stage was the following six-day 0.94 W/m2 white light irradiation culture, and the third-stage was 4.70 W/m2 white light irradiation culture until the end of fermentation. During the three-stage culture of G. lucidum, the gradual decrease trend of GA content after day 2 was turned around, which suggested that 0.94 W/m2 white light irradiation was beneficial for the metabolic flux towards the GA biosynthesis. The maximal GA content of 3.1 ± 0.1 mg/100 mg DW was obtained, which was higher by 41% compared to the two-stage culture. The maximal GA production (i.e., 466.3 ± 24.1 mg/L) and productivity (i.e., 38.9 mg/L per day) in the three-stage culture were 69 and 101% higher than those obtained in the two-stage culture. This is the first report investigating the significance of light irradiation on the medicinal mushroom submerged fermentation. Such work is very helpful to other mushroom fermentations for useful metabolite production. [source] Suspension Culture Process of MethA Tumor Cell for the Production of Heat-Shock Protein Glycoprotein 96: Process Optimization in Spinner FlasksBIOTECHNOLOGY PROGRESS, Issue 6 2007Ya-Jie Tang Heat-shock proteins (HSPs) act like "chaperones", making sure that the cellapos;s proteins are in the right shape and in the right place at the right time. Heat-shock protein glycoprotein 96 (gp96) is a member of the HSP90 protein family, which chaperones a number of molecules in protein folding and transportation. Heat-shock protein gp96 serves as a natural adjuvant for chaperoning antigenic peptides into the immune surveillance pathways. Currently, heat-shock protein gp96 was only isolated from murine and human tissues and cell lines. An animal cell suspension culture process for the production of heat-shock protein gp96 by MethA tumor cell was developed for the first time in spinner flasks. Effects of culture medium and condition were studied to enhance the MethA tumor cell density and the production and productivity of heat-shock protein gp96. Initial glucose concentration had a significant effect on the heat-shock protein gp96 accumulation, and an initial glucose level of 7.0 g/L was desirable for MethA tumor cell growth and heat-shock protein gp96 production and productivity. Cultures at an initial glutamine concentration of 3 and 6 mM were nutritionally limited by glutamine. At an initial glutamine concentration of 6 mM, the maximal viable cell density of 19.90 × 105 cells/mL and the maximal heat-shock protein gp96 production of 4.95 mg/L was obtained. The initial concentration of RPMI 1640 and serum greatly affected the MethA tumor cell culture process. Specifically cultures with lower initial concentration of RPMI 1640 resulted in lower viable cell density and lower heat-shock protein gp96 production. At an initial serum concentration of 8%, the maximal viable cell density of 19.18 × 105 cells/mL and the maximal heat-shock protein gp96 production of 5.67 mg/L was obtained. The spin rate significantly affected the cell culture process in spinner flasks, and a spin rate of 150 rpm was desirable for MethA tumor cell growth and heat-shock protein gp96 production and productivity. Not only the cell density but also the production and productivity of heat-shock protein gp96 attained in this work are the highest reported in the culture of MethA tumor cell. This work offers an effective approach for producing heat-shock protein glycoprotein 96 from the cell culture process. The fundamental information obtained in this study may be useful for the efficient production of heat-shock protein by animal cell suspension culture on a large scale. [source] Perfusion Culture of Hybridoma Cells for Hyperproduction of IgG2a Monoclonal Antibody in a Wave Bioreactor-Perfusion Culture SystemBIOTECHNOLOGY PROGRESS, Issue 1 2007Ya-Jie Tang A novel wave bioreactor-perfusion culture system was developed for highly efficient production of monoclonal antibody IgG2a (mAb) by hybridoma cells. The system consists of a wave bioreactor, a floating membrane cell-retention filter, and a weight-based perfusion controller. A polyethylene membrane filter with a pore size of 7 ,m was floating on the surface of the culture broth for cell retention, eliminating the need for traditional pump around flow loops and external cell separators. A weight-based perfusion controller was designed to balance the medium renewal rate and the harvest rate during perfusion culture. BD Cell mAb Medium (BD Biosciences, CA) was identified to be the optimal basal medium for mAb production during batch culture. A control strategy for perfusion rate (volume of fresh medium/working volume of reactor/day, vvd) was identified as a key factor affecting cell growth and mAb accumulation during perfusion culture, and the optimal control strategy was increasing perfusion rate by 0.15 vvd per day. Average specific mAb production rate was linearly corrected with increasing perfusion rate within the range of investigation. The maximum viable cell density reached 22.3 × 105 and 200.5 × 105 cells/mL in the batch and perfusion culture, respectively, while the corresponding maximum mAb concentration reached 182.4 and 463.6 mg/L and the corresponding maximum total mAb amount was 182.4 and 1406.5 mg, respectively. Not only the yield of viable cell per liter of medium (32.9 × 105 cells/mL per liter medium) and the mAb yield per liter of medium (230.6 mg/L medium) but also the mAb volumetric productivity (33.1 mg/L·day) in perfusion culture were much higher than those (i.e., 22.3 × 105 cells/mL per liter medium, 182.4 mg/L medium, and 20.3 mg/L·day) in batch culture. Relatively fast cell growth and the perfusion culture approach warrant that high biomass and mAb productivity may be obtained in such a novel perfusion culture system (1 L working volume), which offers an alternative approach for producing gram quantity of proteins from industrial cell lines in a liter-size cell culture. The fundamental information obtained in this study may be useful for perfusion culture of hybridoma cells on a large scale. [source] | |||||||||||||||||||