Topic
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.
Papers published on a yearly basis
Papers
More filters
TL;DR: A novel centrifugal impeller bioreactor for shear‐sensitive biological systems was designed by installing a centrifugal‐pumplike impeller in a stirred vessel and showed higher liquid lift capacity and shorter mixing time than the cell lift with comparable dimensions.
Abstract: A novel centrifugal impeller bioreactor for shear-sensitive biological systems was designed by installing a centrifugal-pumplike impeller in a stirred vessel. The fluid circulation, mixing, and liquid velocity profiles in the new bioreactor (5-L) were assessed as functions of the principal impeller designing and bioreactor operating parameters. The performances of the centrifugal impeller bioreactor were compared with those of a widely used cell-lift bioreactor. The newly developed bioreactor showed higher liquid lift capacity and shorter mixing time than the cell lift with comparable dimensions. Furthermore, the experiments of the liquid velocity profiles around an impeller region indicated that the centrifugal impeller bioreactor produced lower shear stress than the cell lift. This conclusion was also supported by evaluating the changes in size distributions of granulated agar particles that were sheared with those two types of impeller.
57 citations
01 Jan 2001
TL;DR: A semicontinuous system was implemented to treat effluents with relatively high concentrations of phenol, by replacing periodically about 22% of the bioreactor operational volume, which obtained phenol removal efficiencies higher than 98.7%.
Abstract: As in many other microorganisms, the growth rate of C. tropicalis is affected by phenol. Be- sides, when the yeast is aerobically cultivated in a medium containing phenol, using a bubble column, the yeast cell flotation phenomenon occurs, which makes the continuous operation of this type of reactor diffi- cult. Therefore, a system of phenol degradation, which recycles the biomass separated by flotation, was devised in this work. In order to reduce the substrate toxicity observed at high phenol concentrations, the bubble column used in the biodegradation studies was fed in a semibatch mode. So, a semicontinuous sys- tem was implemented to treat effluents with relatively high concentrations (> 9,000 ppm) of phenol, by replacing periodically about 22% of the bioreactor operational volume. The phenol removal efficiencies obtained with this system were higher than 98.7%.
57 citations
TL;DR: Polluted surface water was remediated in a bioreactor using biofilms on filamentous bamboo in batch and continuous flow modes and the COD cr removal rate of the enhanced systems increased more than 13% relative to a controlled system.
57 citations
TL;DR: The higher alcohol dehydrogenase activity obtained under reduced oxygen conditions suggests that proliferating cultures adapted to the hypoxic environment by inducing alcoholic fermentation.
Abstract: A bioreactor control system was used to investigate the effects of two dissolved oxygen concentrations (10% and 100%) on the growth and differentiation of Daucus carota L. cell cultures. The strategy used allowed the dissolved oxygen concentration to be controlled without the need for changing either the agitator speed or the total gas flow rate. During the proliferation phase, reducing oxygen resulted in a lower growth rate and in a delay in sugar uptake kinetics. Nonetheless, varying levels of oxygen were observed to have no effect on the final dry biomass. The higher alcohol dehydrogenase activity obtained under reduced oxygen conditions suggests that proliferating cultures adapted to the hypoxic environment by inducing alcoholic fermentation. Cell differentiation was highly sensitive to reduced oxygen since under this condition, the somatic embryo production was inhibited by about 75%. Sugar uptake and embryo formation were also delayed.
57 citations
TL;DR: The growth and metabolism of Saccharomyces cerevisiae was studied in steady‐state chemostat cultures under conditions of scarce oxygen and excess glucose, suggesting that ATP has a critical role in dictating the biomass concentration in micro‐aerobic culture.
Abstract: The growth and metabolism of Saccharomyces cerevisiae was studied in steady-state chemostat cultures under conditions of scarce oxygen and excess glucose. The specific ethanol productivity and specific glucose uptake rate were stimulated by 50% within a narrow range of air/nitrogen mixtures to the fermentor. Fermentation was inhibited at slightly higher and lower air/nitrogen ratios, confirming similar results by previous investigators. This stimulation could not be caused by obvious mechanisms, such as the Pasteur or Crabtree effects. Since this maximum in the fermentation rate occurred in a steady-state chemostat and at a constant dilution rate, the ATP yield of the culture necessarily attained a minimum. Thus, changes in the energetic efficiency of growth or the degree of wasting of ATP were surmised. The steady-state biomass concentration at various oxygenation rates exhibited hysteresis phenomena. Ignition and extinction of the biomass concentration occurred as critical oxygen feed rates were passed. The hysteresis was prevented by adding yeast extract to or reducing the antifoam concentration in the medium. These medium alterations had the simultaneous effect of stimulating the fermentation rate, suggesting that ATP has a critical role in dictating the biomass concentration in micro-aerobic culture. Silicone polymer antifoam was found to stimulate glycerol production at the expense of ethanol production, having consequences for the energy generation and the biomass concentration of the culture.
57 citations