Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • bioreactor  (1)
  • fermentation monitoring  (1)
  • high cell density  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cytotechnology 18 (1995), S. 3-8 
    ISSN: 1573-0778
    Keywords: bioreactor ; cellular therapies ; gene therapy ; therapeutic proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Large scale animal cell culture for the production of complex therapeutic proteins has been a major success of the biotechnology industry. Today, approximately half of the $ 5 billion annual turnover of the biotechnology industry is based upon this technology, in many cases with reactors of more than 10 m3. As we look towards the 21 st century, however, we can see novel approaches to the production of therapeutic proteins, by means of gene and cellular therapies. These technologies present new engineering challenges to the animal cell technologist. Are we prepared to meet these challenges? The needs include: small-scale reactors for the preparation of autologous cell lines, methods for the production of viruses to be used as vectors in gene therapy, artificial organ and the processing of xenogenic cell lines and tissues for cellular implants in humans. More attention should be given to three-dimensional cell cultures. Mass transfer considerations need to be extended beyond just oxygen transfer, to include cellular communication in small systems; this is becoming increasingly important for the control and optimise growth and product formation. Apart from improvements of large-scale systems, substantial advantages could be gained by studying new methods for the production and delivery of therapeutic proteins, using small-scale cell culture systems. We should adapt teaching, regulatory, patent and clinical infrastructure to meet this challenge in a harmonious way.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 39 (1992), S. 293-304 
    ISSN: 0006-3592
    Keywords: control ; fermentation ; baker's yeast ; high cell density ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A methodology for the design and evalution of bioprocess control strategies is presented. The strategies manage nutrient supply with demand and vary with the metabolic condition and phase of fermentation operation. Six carbon source addition strategies are based on different combinations of available measurements; they are described and evaluated under different operating conditions for yeast cultivation. It is concluded that a single control strategy is not the most appropriate under all possible operating conditions. An oxygen uptake rate-based control strategy performs better with a mean respiratory quotient (RQ) value less than 1.1 during an oxygen limitation than an ethanol control strategy which had a mean RQ of 14. The designed strategies and an approach of applying the strategy that best matches fermentation conditions consistently enables achievement of high cell densities 78.7 g DCW/L and yields 0.50 g DCW/g glucose as the mean values for three fermentations.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0006-3592
    Keywords: nitrogenase ; mass spectrometry ; fermentation monitoring ; Azotobacter vinelandii ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This study evaluated the feasibility of monitoring nitro-genase activity in situ through measurement of N2 uptake rate (NUR) using off-gas mass spectrometry. Four 50-L cultures of Azotobacter vinelandii were grown aer-obically in nitrogen-free medium to cell densities of 1.0-1.3gL-1 magnetic-sector mass spectrometer was used to monitor NUR along with other gas exchange rates. The small specific uptake rate (1.2 mmol g-1 h-1) and low cell density were found to lead to a NUR below the measurement accuracy limits under normal conditions. An operating strategy and feed gas mixture (40% O2, 45% N2 15% Ar) were designed to improve the signal-to-noise ratio while maintaining dissolved O2 and N2 levels in desired ranges. The fraction of N2 removed from the air stream was increased approximately 5-fold from 0.2% to 1.0% and the measurement noise was reduced 25-fold from a baseline of ±5to ±0.2 mmol L-1 h-1. The NUR measurements were compared against in vivo and in vitro acetylene reduction assays as well as on-line cell growth rate measurements. While electron transfer requirements predict an NUR-to-acetylene reduction rate ratio of 0.33, measured ratios for the in vivo and in vitro assays were 0.8 and 0.44, respectively. This suggests that other rate-limiting steps were present in the case of the in vivo assay. In accordance with reports in the literature, no concomitant hydrogen evolution was detected. This is the first reported continuous and direct measurement of NUR in fermentation and demonstrates a novel approach for improving measurement accuracy through rational adjustment of operating conditions. The technique has potential to provide useful insight for development and control of microbial nitrogen fixation processes.© John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...