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.

Mathematical Modeling of Three-Dimensional Cell Cultures in Perfusion Bioreactors

Abstract: Tissue engineering involves growing cells within supporting scaffolds to obtain structures for in vivo implantation with adequate functionality. Obtaining a proper oxygen supply, high cell density, and a uniform cell distribution in a three-dimensional (3D) growth support are important challenges. Both experiments and quantitative mathematical models are needed to better understand the physical, mechanical, and biochemical phenomena and for the rational design of suitable reactor geometries and operating protocols for the production of functional engineered artificial grafts. In this work, a comprehensive mathematical model of convection and diffusion in a perfusion bioreactor, combined with cell growth kinetics, is developed. The model describes the spatial−temporal evolution of oxygen concentration and cell density within a 3D polymeric scaffold. The fluid dynamics of the medium flow inside the bioreactor is described through the Navier−Stokes equations for incompressible fluids while convection through...

Acetate production from whey lactose using co-immobilized cells of homolactic and homoacetic bacteria in a fibrous-bed bioreactor

Abstract: Acetate was produced from whey lactose in batch and fed-batch fermentations using co-immobilized cells of Clostridium formicoaceticum and Lactococcus lactis. The cells were immobilized in a spirally wound fibrous sheet packed in a 0.45-L column reactor, with liquid circulated through a 5-L stirred-tank fermentor. Industrial-grade nitrogen sources, including corn steep liquor, casein hydrolysate, and yeast hydrolysate, were studied as inexpensive nutrient supplements to whey permeate and acid whey. Supplementation with either 2.5% (v/v) corn steep liquor or 1.5 g/L casein hydrolysate was adequate for the cocultured fermentation. The overall acetic acid yield from lactose was 0.9 g/g, and the productivity was 0.25 g/(L h). Both lactate and acetate at high concentrations inhibited the homoacetic fermentation. To overcome these inhibitions, fed-batch fermentations were used to keep lactate concentration low and to adapt cells to high-concentration acetate. The final acetate concentration obtained in the fed-batch fermentation was 75 g/L, which was the highest acetate concentration ever produced by C. formicoaceticum. Even at this high acetate concentration, the overall productivity was 0.18 g/(L h) based on the total medium volume and 1.23 g/(L h) based on the fibrous-bed reactor volume. The cells isolated from the fibrous-bed bioreactor at the end of this study were more tolerant to acetic acid than the original culture used to seed the bioreactor, indicating that adaptation and natural selection of acetate-tolerant strains occurred. This cocultured fermentation process could be used to produce a low-cost acetate deicer from whey permeate and acid whey.

Enhanced growth of sf‐9 cells to a maximum density of 5.2 × 107 cells per mL and production of β‐galactosidase at high cell density by fed batch culture

Abstract: Significant improvement in cell growth and protein production has been achieved in Sf-9 insect cell cultures using pulse additions of multicomponent nutrient feed concentrates (Bedard et al., 1994; Chan et al., 1998). The present work focuses on investigating an alternative feeding strategy wherein the nutrients are fed in a semi continuous manner. Fed batch culture experiments were carried out to compare the two different feeding strategies, pulse and semi continuous and a process developed to achieve a cell density of 5.2 x 10(7) cells/mL of Sf-9 cells in a 3.5 L bioreactor. Production of recombinant protein beta-galactosidase was carried out by infecting the cells with baculovirus at a MOI of 10 at cell densities of 17 x 10(6)cells/mL. Specific productivity could be maintained at cell densities as high as 14 x 10(6) cells/mL. The results presented indicate that the feeding method can provide significant improvements in the performance with a reduction in the amount of total nutrients added. On-line monitoring of the culture using the capacitance probe showed that the capacitance probe can be used successfully to monitor the biomass and infection process even at higher cell densities.