Bioprocess

About: Bioprocess is a research topic. Over the lifetime, 2219 publications have been published within this topic receiving 50972 citations.

Recombinant bioprocess optimization for heterologous protein production using two-stage, cyclic fed-batch culture.

Abstract: A two-stage, cyclic fed-batch bioprocess was designed, and its performance evaluated to improve rice α-amylase productivity by the yeast Yarrowia lipolytica SMY2 (MatA, ade1, ura3, xpr2), ATCC 201847, containing a replicative plasmid coding for a rice α-amlyase. Transcription of the recombinant gene is controlled by the XPR2 promoter. The first stage (or growth stage) was operated in the fed-batch mode, and the growth medium, designed to maintain a constant high cell density (i.e., 60 g/l), was fed according to a predetermined and preprogrammed optimal feed rate which, in turn, maintained the specific cell growth rate at an optimal value (i.e., 0.1 h−1). Typically, when the volume in the first stage reached a preset value, a portion of culture broth (i.e., 55%) was transferred to the second stage (or production stage). The remaining cells in the growth stage were then fed with fresh growth medium according to the bioprocess control strategy developed, while induction of α-amylase expression and its production was taking place in the second stage. The second stage was also operated in the fed-batch mode, and the production medium designed to maintain a constant high cell density and high productivity of heterologous protein was fed at a predetermined and preprogrammed rate, which maintained the specific cell growth rate at an optimal level. The volumetric α-amylase productivity achieved (1835 units l−1 h−1) from the two-stage, cyclic fed-batch culture process was twofold higher than that of the fed-batch culture process. The genetic stability of the recombinant strain and the design of optimal media for growth and production stages are also critically important to a successful implementation of the two-stage, cyclic fed-batch process for production of heterologous protein.

Advanced near-infrared monitor for stable real-time measurement and control of Pichia pastoris bioprocesses

Abstract: Near-infrared spectroscopy is considered to be one of the most promising spectroscopic techniques for upstream bioprocess monitoring and control. Traditionally the nature of near-infrared spectroscopy has demanded multivariate calibration models to relate spectral variance to analyte concentrations. The resulting analytical measurements have proven unreliable for the measurement of metabolic substrates for bioprocess batches performed outside the calibration process. This paper presents results of an innovative near-infrared spectroscopic monitor designed to follow the concentrations of glycerol and methanol, as well as biomass, in real time and continuously during the production of a monoclonal antibody by a Pichia pastoris high cell density process. A solid state instrumental design overcomes the ruggedness limitations of conventional interferometer-based spectrometers. Accurate monitoring of glycerol, methanol, and biomass is demonstrated over 274 days postcalibration. In addition, the first example of feedback control to maintain constant methanol concentrations, as low as 1 g/L, is presented. Postcalibration measurements over a 9-month period illustrate a level of reliability and robustness that promises its adoption for online bioprocess monitoring throughout product development, from early laboratory research and development to pilot and manufacturing scale operation. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:749–759, 2014

Foam formation and control in bioreactors

Abstract: The generation of foam during the course of a bioprocess remains a major technological challenge to be resolved and needs further investigation. The foaming tendency of the cultivation media used in bioreactors induces various direct,that is microbial cells stripping and contamination, as well as indirect adverse effects, that is modification of the properties of the medium subsequent to the addition of chemical antifoam leading to toxic effects at the level of the microbial metabolism and fouling of the downstream processing equipment. In this work, the mechanisms leading to foam formation are described at the molecular level (adsorption of surface-active molecule at the gas–liquid interface), and also at the process level. In view of the potential foam-associated problems, special attention is given to the level of the compatibility of the intensification of the gas–liquid operation in bioreactors. Due to these considerations, both the chemical and mechanical antifoam techniques have been evolved. Numerous new antifoam formulations and original combinations of chemical antifoams have been especially designed in order to meet the specific requirements of bioprocesses. Original mechanical techniques to prevent foam formation in bioreactors have been elaborated from combined knowledge involving the fluid dynamics of gas–liquid dispersion and interfacial processes (e.g. the “stirring as foam disruption” concept). Keywords: antifoam; mechanical defoamer; gas–liquid dispersion; bioprocess; mixing

Mixotrophic biorefinery: A promising algal platform for sustainable biofuels and high value coproducts

Abstract: Mixotrophic microalgae cultivation is becoming the most promising and sustainable process for sustainable biosynthesis of biochemicals and biofuels. It offers significantly higher productivity to cope up the key challenges to develop industrial algal processes. Mixotrophic cultivation strategy (MCS) leads to better productivity due to the unique metabolic capacity of microalgae by combining both photosynthesis and oxidative metabolic pathways for biomass generation. The capacity of the mixotrophic phenomenon is being investigated for sustainable bioprocess development ensuring higher energy recovery, economy, environmental and social benefits. However, developments are in pipeline and still to attain a commercial phase. In this article, recent technological developments in MC bioprocess for biofuels production are discussed; synergistic carbon and energy regulation, critical discussion up on commercially important organic carbon sources and their effects on MC bioprocessing have been demonstrated; Moreover, the prospective and challenges of higher-scale MC-linked bioprocessing and future direction on technology development have been addressed.

Economic analysis of Uricase production under uncertainty: Contrast of chromatographic purification and aqueous two-phase extraction (with and without PEG recycle)

Abstract: Uricase is the enzyme responsible for the breakdown of uric acid, the key molecule leading to gout in humans, into allantoin, but it is absent in humans. It has been produced as a PEGylated pharmaceutical where the purification is performed through three sequential chromatographic columns. More recently an aqueous two-phase system (ATPS) was reported that could recover Uricase with high yield and purity. Although the use of ATPS can decrease cost and time, it also generates a large amount of waste. The ability, therefore, to recycle key components of ATPS is of interest. Economic modelling is a powerful tool that allows the bioprocess engineer to compare possible outcomes and find areas where further research or optimization might be required without recourse to extensive experiments and time. This research provides an economic analysis using the commercial software BioSolve of the strategies for Uricase production: chromatographic and ATPS, and includes a third bioprocess that uses material recycling. The key parameters that affect the process the most were located via a sensitivity analysis and evaluated with a Monte Carlo analysis. Results show that ATPS is far less expensive than chromatography, but that there is an area where the cost of production of both bioprocesses overlap. Furthermore, recycling does not impact the cost of production. This study serves to provide a framework for the economic analysis of Uricase production using alternative techniques.