Fermentation

Model-Based Process Monitoring of Algae Cultures Using eve Software

In bioreactor processes, the on-line monitoring of key parameters relies on the use of adequate sensors. In this article, we implement model-based software sensors to monitor nitrate concentrations in an algae batch process. Nitrate concentration is a crucial component in algae growth, and its assessment is used to achieve optimal growth conditions or to determine optimal harvest times. Batch cultivation of the algae Chlamydomonas reinhardtii is carried out in a Labfors 5 airlift photobioreactor provided by INFORS-HT. By means of…

Engineering Alternatives: Modern Technology Enables Expression System Developers to Think Beyond CHO Cells

Major biopharmaceutical companies are teaming up with academics and the Bill & Melinda Gates Foundation to develop new biomanufacturing cell lines and methods. The project — known as the AltHost Consortium — is exploring innovative ways to produce biologics and vaccines for clinical usage in diseases from diabetes to cancer. Lead researcher J. Christopher Love at the Massachusetts Institute of Technology (MIT) likens this precompetitive, open-access collaboration to the early days of the biopharmaceutical industry. “When biomanufacturing first emerged as…

Oxygen Control Strategy and Yield of Recombinant Antibody Fragments Produced in Fermentation

Immunoglobulin molecules are used extensively in therapeutic treatments, diagnostic applications, and fundamental academic research. Traditionally, full-length antibodies and smaller fragments such as the recombinant antigen-binding fragment (rFab) are produced through mammalian cell culture. rFabs also are small enough to be produced in Escherichia coli through fermentation (1, 2). Because disulfide bonds cannot be formed efficiently in the reducing cytoplasm of E. coli, rFabs are supplemented most commonly with a signal sequence that directs them to the more oxidizing bacterial periplasm…

eBook: Microbial Expression — The Right Choice for Large Peptides and Small Proteins

Although animal cell culture has dominated the biopharmaceutical industry for some years now, microbial expression remains important for producing proteins that don’t require posttranslational modifications — or only those that prokaryotic microbes can perform. It also offers an affordable option for antibody fragments and gene therapies. Microbes may be less fragile than animal cells, and they do require simpler media, but they present other challenges related to temperature management and oxygen transfer in culture. Wherever practical, bacterial expression is preferred…

Comparative Study of Single-Use and Reusable Fermentors: Production of Recombinant Proteins Through Bacterial Fermentation

Single-use bioreactors have become widely accepted and well established for cell culture applications in the biopharmaceutical industry for over a decade (1). Abbott Diagnostics has moved into this technology already for commercial production of some biologic molecules. However, single-use systems (SUSs) are rarely available for microbial applications, mostly because of the technical challenge in designing cost-effective SUSs that can meet high oxygen transfer needs and remove excessive heat generated during fermentation. Thus, an important part of our biologics manufacturing —…

eBook: Of Microbrews and Medicines — Understanding Their Similarities and Differences in Bioprocessing Can Help Improve Yields and Quality While Reducing Cost

Meeting a biopharmaceutical scientist or engineer who proclaims a love for brewing is not surprising. Perhaps it’s because of the challenge of mixing raw ingredients together and waiting patiently for the final product, maybe it’s the hands-on nature of the equipment or the data analytics entertainment, or it just might be the simple joy of creating something. Whatever attracts a scientist or engineer to making medicines and/or craft brews, a surprising number of principles hold true for both bioprocesses despite…

CO2, O2, and Biomass Monitoring in Escherichia coli Shake Flask Culture: Following Glucose–Glycerin Diauxie Online

Carbon dioxide (CO2) is an important parameter in microbial cultures because it can inhibit or stimulate growth under certain conditions. In our experiment, we monitored Escherichia coli diauxie growth phases online and focused on dissolved CO2 (dCO2) and oxygen readings. We assessed diauxic growth in medium containing glycerin and glucose online with the SFR vario system (from PreSens), which optically measures oxygen, pH, and biomass in an Erlenmeyer flask. The shake flask contained an oxygen sensor spot and an optical…

Orbital Shaking and Acoustic-Resonance Mixing: Comparing Culture Characteristics

Production of recombinant proteins usually happens in suspension cultures, with oxygen limitation playing a major role. Oxygen and nutrition feeds are of great significance to aerobic suspension cultures. Oxygen is often the controlling factor in orbital shaken systems because oxygen transfer occurs only through diffusion, which is limited by gas-exchange surface and mixing characteristics. Here, we compare growth characteristics of microbial cultures in a standard shaken incubator with those of cultures in a RAMbio fermentation system, paying particular attention to…

Single-Use Processing for Microbial Fermentations

During the past decade, single‑use bioprocessing has emerged as a standard platform for current good manufacturing practice (CGMP) mammalian cell culture. Biomanufacturers have come to appreciate the benefits of lower capital and operating costs, reduced contamination risk, continuity from early development through manufacturing, flexibility, and sustainability (1). Disposable cell‑culture vessels have gained wide acceptance because their performance duplicates that of stainless‑steel, fixed‑tank bioreactors, with which manufacturers have extensive experience. This is no accident: Single‑use bioreactors use stainless–steel engineering principles, particularly…

Automation of Microbioreactors

Current methodologies in genetics and microbiology enable researchers to influence metabolic pathways of microbial cells in many directions. Beside the academic interest in investigating fundamental functions in metabolic pathways, commercial production of valuable compounds by microbial hosts is state of the art. For example, such products include enzymes (lipases, proteases, phytases), therapeutic agents (insulin, antibodies), bulk chemicals (lysine, glutamate, citric acid), or the microbial cells themselves (used in brewing or milk processing), with therapeutic agents probably the fastest growing market.…