Bioreactor

About: Bioreactor is a research topic. Over the lifetime, 9980 publications have been published within this topic receiving 192690 citations. The topic is also known as: bioreactors.

An immobilized cell bioprocess for the removal of heavy metals from aqueous flows.

Abstract: Microorganisms can be used to remove toxic heavy metals from liquid industrial wastes. In addition to the chemical toxicity of many of the latter, the production of long-lived nuclides from nuclear power programmes has introduced additional radiotoxicological hazards. Associated problems of the presence of contaminating, non-metal co-pollutants and the presentation of dilute, high-volume wastes have received little attention. Traditional biotechnological waste treatments have relied either on the use of non-living biomass ('biosorption') or on the accumulation of metals by living cells with the associated problems of metal toxicity effects and the requirements for cell viability or growth. Identification of an enzymically-mediated metal accumulation step can permit decoupling of cell growth from metal accumulation. Using pre-grown biomass immobilized in a flow-through filter ('bioreactor') the metal-accumulative bioprocess can be described accurately applying traditional Michaelis-Menten kinetics. The effect of co-pollutants can be then quantified in order to run the bioreactor in the most efficient way.

Application of bioreactors for large-scale micropropagation systems of plants

Abstract: The application of bioreactor culture techniques for plant micropropagation is regarded as one of the ways to reduce production cost by scaling-up and automation. Recent experiments are restricted to a small number of species that, however, demonstrate the feasibility of this technology. Periodic immersion liquid culture using ebb and flood system and column-type bubble bioreactors equipped with a raft support system to maintain plant tissues at the air and liquid interface were found to be suitable for micropropagation of plants via the organogenic pathway. Balloon-type bubble bioreactors proved to be fit for micropropagation via somatic embryogenesis with less shear stress on cultured cells. Several cultivars of Lilium were successfully propagated using a two-stage culture method in one bioreactor. A large number of small-scale segments were cultured for 4 wk with periodic immersion liquid culture to induce multiple bulblets from each segment, then the bulblet induction medium was changed into bulblet growth medium by employing a submerged liquid bioreactor system. This culture method resulted in a nearly 10-fold increase in bulblet growth compared to conventional culture with solid medium. About 20 000 cuttings of virus-free potato could be obtained from 120 singlenode explants in a 20-liter balloon-type bubble bioreactor after 8 wk of culture. The percentage of ex vitro survival and root induction of the cuttings was more than 95%. Other successful results were obtained from the micropropagation and transplant production of chrysanthemum, sweetpotato, Chinese foxglove. Propagation systems via somatic embryogenesis in Acanthopanax koreanum and thornless Aralia elata were established using a liquid suspension of embryogenic determined cells. More than 500 000 somatic embryos in different stages were harvested from a 10-liter balloon-type bubble bioreactor after a 6-wk culture. Further development of these embryos in solid medium and eventually in the field was successful. The bioreactor system could reduce initial and operational cost for micropropagation, but further development of sophisticated technology might be needed to apply this system to plant micropropagation industries.

Microbioreactor arrays with integrated mixers and fluid injectors for high-throughput experimentation with pH and dissolved oxygen control

Abstract: We have developed an integrated array of microbioreactors, with 100 µL working volume, comprising a peristaltic oxygenating mixer and microfluidic injectors. These integrated devices were fabricated in a single chip and can provide a high oxygen transfer rate (kLa ≈ 0.1 s−1) without introducing bubbles, and closed loop control over dissolved oxygen and pH (±0.1). The system was capable of supporting eight simultaneous Escherichia coli fermentations to cell densities greater than 13 g-dcw L−1 (1 cm OD650nm > 40). This cell density was comparable to that achieved in a 4 litre reference fermentation, conducted with the same strain, in a bench scale stirred tank bioreactor and is more than four times higher than cell densities previously achieved in microbioreactors. Bubble free oxygenation permitted near real time optical density measurements which could be used to observe subtle changes in the growth rate and infer changes in the state of microbial genetic networks. Our system provides a platform for the study of the interaction of microbial populations with different environmental conditions, which has applications in basic science and industrial bioprocess development. We leverage the advantages of microfluidic integration to deliver a disposable, parallel bioreactor in a single chip, rather than robotically multiplexing independent bioreactors, which opens a new avenue for scaling small scale bioreactor arrays with the capabilities of bench scale stirred tank reactors.