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#bioreactors

3 public questions tagged with this topic.

Animal Tissue Culture 1

Spinner flasks are mainly used for:

Adherent culture surface area becomes limiting scale because monolayer occupies only flat two dimensional polystyrene, maximum about 10^5 cells per square centimeter requiring large factory facilities with robotic arms to produce billions cells for vaccine manufacturing. Suspension adaptation overcomes limitation growing cells in three dimensional liquid volume without need for enzymatic detachment trypsin subculture reducing labor and contamination risk, suitable for scale-up to 2000 liter stirred tank bioreactors used for monoclonal antibody production. Spinner flasks represent laboratory scale suspension culture device: glass or disposable polycarbonate vessels typically 100 ml to 3 liter with centrally placed magnetic stir bar impeller rotating via external stir plate at thirty to sixty revolutions per minute generating gentle fluid motion via Couette flow, maintaining homogeneous distribution nutrients glucose glutamine oxygen dissolved via surface aeration and metabolic waste lactate ammonia preventing gradients. This mechanistic insight supports diagnostic and therapeutic applications while reinforcing core immunological and cell biology principles taught in advanced curricula.

Ref: Freshney spinner flask 30-60 rpm suspension mixing Krogh diffusion; ATCC Cell Culture suspension adaptation perfusion oxygen kLa.

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Bioremediation

Bioreactors used in bioremediation are:

Bioreactors in bioremediation function as engineered controlled systems where dissolved oxygen via sparging, agitation 100 to 500 rpm, pH 6 to 8 via dosing, temperature 20 to 35 Celsius via jackets, retention time 0.5 to 10 days, redox potential via ORP probes, and nutrient supply precisely manipulated via controllers maximizing degradation kinetics modeled by Monod equations. Configurations include stirred-tank slurry reactors 10 to 30 percent solids, packed-bed biofilters with immobilized biofilm for air and water, fluidized beds using sand carriers enhancing retention above 10 g per L, and membrane bioreactors retaining slow dechlorinators. Unlike uncontrolled natural attenuation relying on passive diffusion, open wetlands or root zones fluctuating diurnally, bioreactors provide containment preventing spread, capture off-gases via activated carbon, achieve endpoints within days to weeks. Real-time monitoring via respirometry, chromatography and qPCR of catabolic genes catA informs adaptive control optimizing aeration and feeding, though capital investment and complexity higher than in situ approaches, justifiable for industrial effluents with high contaminant loads.

Ref: Chisti Bioreactors in Waste Management; EPA Bioreactor Design Manual 2002; Wang et al. Bioprocess Engineering principles.

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