High-performance Bioreactor Research Articles

A high productivity bioprocess for obtaining metallic copper from printed circuit boards (PCBs)

PCBs constitute a residue rich in metals, among which copper stands out due to its majority content, much higher than that found in natural deposits, so that it is a potential secondary resource. Many attempts have been made to recover copper via biohydrometallurgy because it is an environmentally friendly route, however, one of its main drawbacks is the low productivity achieved.A global process based on circularity for obtaining copper cathodes from PCBs is proposed. First, PCBs from end-of-life mobile phones are shred to sizes between 800 and 2000 µm. Copper is leached from these pieces in a continuous stirred tank reactor (CSTR) at high ferric concentration, at a moderate temperature of 60 °C reaching dissolution rate higher than 1 g/L·h and a yield of 99 %. The solution that leaves the CSTR with concentrations of up to 10 g/L of Cu is passed through a high-performance bioreactor for the regeneration of Fe(III). A biooxidation rate of 1.3 g/L⋅h was achieved, and no inhibition was observed.Concurrently, copper is recovered in metallic state by solvent extraction and electrowinning with recirculation streams becoming a more profitable and sustainable complete global process.

Using a high-performance bioreactor system to cultivate peanut kernels for the induction of stilbenoids

ABSTRACTResveratrol and its bioactive component, trans-arachidin-1, which is extracted from Arachis hypogaea, can be taken as dietary supplements to promote health and potentially to extend lifespan. In this study, a high-performance bioreactor was developed. The rotation of the chamber, temperature, humidity, and CO2 concentration were 76–89 rpm, 26–35°C, 75%, and 850 ppm, respectively. During incubation, sets of peanut slices were sampled at intervals and analyzed with high-performance liquid chromatography (HPLC). The stilbenoid profiles varied quantitatively and qualitatively with the time of incubation. After 24 h of incubation, the slices were dried, ground, and defatted with n-hexane. The slices were then extracted and subjected to HPLC analysis. The trans-resveratrol, trans-arachidin-1, trans-arachidin-3, and trans-isopentadienyl resveratrol levels were 0.374, 1.507, 8.558, and 5.246 mg/g defatted powder, respectively. We demonstrated that the designed device (equipped with a human–machine interface and a programmable logic controller) can perform real-time monitoring of the ambient parameters.

A Roadmap for the Design of Bioreactors in Mechanobiological Research and Engineering of Load-Bearing Tissues

In the field of tissue engineering, a bioreactor is a valuable instrument that mimics a physiological environment to maintain live tissues in vitro. Although bioreactors are conceptually relatively simple, the vast majority of current bioreactors (commercial and custom-built) are not fully adapted to current research needs. Designing the optimal bioreactor requires a very thorough approach to a series of steps in the product development process. These four basic steps are: (1) identifying the needs and technical requirements, (2) defining and evaluating the related concepts, (3) designing the apparatus and drawing up the blueprints, and (4) building and validating the apparatus. Furthermore, the design has to be adapted to the specific purpose of the research and how the tissues will be used. In the emerging field of bioreactor research, roadmaps are needed to assist tissue engineering researchers as they embark on this process. The necessary multidisciplinary expertise covering micromechanical design, mechatronics, viscoelasticity, tissue culture, and human ergonomics is not necessarily available to all research teams. Therefore, the challenge of adapting and conducting each step in the product development process is significant. This paper details our proposal for a roadmap to accompany researchers in identifying their needs and technical requirements: step one in the product development process. Our roadmap proposal is set up in two phases. Phase 1 is based on the analysis of the bioreactor use cycle and phase 2 is based on the analysis of one specific and critical step in the use cycle: conducting stimulation and characterization protocols with the bioreactor. A meticulous approach to these two phases minimizes the risk of forgetting important requirements and strengthens the probability of acquiring or designing a high performance bioreactor.

Immobilization of lipase onto cellulose ultrafine fiber membrane for oil hydrolysis in high performance bioreactor

Practical application of biphasic enzyme-immobilized membrane bioreactors (EMBR) requires efficient loading of the enzyme with retention of enzymatic activity. Here, we report a method to fabricate an ultrafine fiber membrane conjugated to lipase with high levels of enzyme loading and activity retention. A cellulose acetate (CA) non-woven ultrafine fiber membrane was prepared with 200 nm nominal fiber diameter by electrospinning, followed by alkaline hydrolysis to obtain regenerated cellulose (RC). The RC ultrafine fiber membrane was oxidized by exposure to NaIO4, simultaneously generating aldehyde groups to couple with pentaethylenehexamine (PEHA) as a spacer for lipase immobilization. A biphasic EMBR was assembled with the PEHA-modified and lipase-immobilized membranes. The effect of operation variables, namely aqueous-phase system, reaction pH, accelerant (sodium taurocholate) content, reaction temperature, and membrane usage on the performance of this bioreactor was investigated with the hydrolysis of olive oil. A bioreactor activity as high as 9.83 × 104 U/m2 was obtained under optimum operational conditions.

The investigation of dairy industry wastewater treatment in a biological high performance membrane system

The dairy industry is generally considered to be the largest source of food processing wastewater in many countries. The highly variable nature of dairy wastewaters in terms of volumes and flowrates and in terms of high organic materials contents such as COD 921–9004 mg L −1, BOD 483–6080 mg L −1, TN of 8–230 mg L −1 and SS of 134–804 mg L −1 makes the choice of an effective wastewater treatment regime difficult. A high performance bioreactor, an aerobic jet loop reactor, combined with a ceramic membrane filtration unit, was used to investigate its suitability for the treatment of the dairy processing wastewater. The oxygen transfer rates of the bioreactor were found to be very high (100–285 h −1) on the operating conditions. A loading rate of 53 kg COD m −3 d −1 resulted in 97–98% COD removal efficiencies under 3 h hydraulic retention time. The high MLSS concentrations could be retained in the system (up to 38,000 mg L −1) with the contribution of UF (ultrafiltration) unit. During the filtration of activated sludge, the fluxes decreased with increasing MLSS. Cake formation fouling was determined as dominant fouling mechanisms. The results demonstrate that jet loop membrane bioreactor system was a suitable and effective treatment choice for treating dairy industry wastewater.

An improved gas distribution system for anaerobic screening of multiple microbial cultures

A cultivation set-up for multiple cultures has been designed that can be used for anaerobic screening for quantitative changes in growth rate or other analyses, e.g. protein composition of different strains. The developed gas distribution system provides a reproducible level of anaerobicity in 30 cultivation flasks and resembles the open system of a high-performance bioreactor in that it ensures cultivation at atmospheric pressure and avoids supersaturation of carbon dioxide. The system is cheap and user-friendly and allows rapid screenings of many strains simultaneously.

97/05134 Treatment of an industrial wastewater having a high level of organic pollutants with a combination of high-performance bioreactor and ultrafiltration: Suprihatin, S. et al. Chemical -Ing. -Tech., 1997, 69, (7), 996–999. (In German)

97/05134 Treatment of an industrial wastewater having a high level of organic pollutants with a combination of high-performance bioreactor and ultrafiltration: Suprihatin, S. et al. Chemical -Ing. -Tech., 1997, 69, (7), 996–999. (In German)

An attempt to add biological functions by genetic engineering in order to produce high-performance bioreactor cells for hybrid artificial liver: transfection of glutamine synthetase into Chinese hamster ovary (CHO) cell.

In the course of immortalization, hepatocyte cell lines lose their original differentiated functions, such as ammonia removal and urea formation, drug metabolism, serum protein synthesis, etc. (Enosawa et al., Cell Transplant. 5:S39-S40; 1996). With the aim of adding lost or deficient functions and producing cell lines for the bioreactor of a hybrid artificial liver, rat glutamine synthetase (GS) gene was transfected into Chinese hamster ovary (CHO) cells, because it is able to lower the ammonia level. The GS gene-inserted pSV2 plasmid was transfected into the CHO-K1 line by electroporation. Transfected CHO (GS-CHO) cells were cultured in a glutamine-free medium containing ammonia, glutamic acid, and the GS inhibitor methionine sulfoximine (MSX). The MSX concentration was increased stepwise from 25 mumol/L to 1600 mumol/L to amplify the GS gene. In several GS-CHO sublines resistant to 300-1600 mumol/L of MSX, the specific activities of GS were increased from 0.2 x 10(4) to 1.7-2.9 x 10(4) unit/10(6) cells. When the amplified GS-CHO cells were cultured in the ammonia-containing medium, a slow but steady decrease of the ammonia level was observed when the level was high. Finally, the prospect of genetically modulated cells for bioreactors in the hybrid artificial liver is discussed.

An attempt to add biological functions by genetic engineering in order to produce high-performance bioreactor cells for hybrid artificial liver: Transfection of glutamine synthetase into Chinese hamster ovary (CHO) cell

In the course of immortalization, hepatocyte cell lines lose their original differentiated functions, such as ammonia removal and urea formation, drug metabolism, serum protein synthesis, etc. (Enosawa et al., Cell Transplant. 5:S39-S40; 1996). With the aim of adding lost or deficient functions and producing cell lines for the bioreactor of a hybrid artificial liver, rat glutamine synthetase (GS) gene was transfected into Chinese hamster ovary (CHO) cells, because it is able to lower the ammonia level. The GS gene-inserted pSV2 plasmid was transfected into the CHO-K1 line by electroporation. Transfected CHO (GS-CHO) cells were cultured in a glutamine-free medium containing ammonia, glutamic acid, and the GS inhibitor methionine sulfoximine (MSX). The MSX concentration was increased stepwise from 25 μmol/L to 1600 μmol/L to amplify the GS gene. In several GS-CHO sublines resistant to 300–1600 μmol/L of MSX, the specific activities of GS were increased from 0.2 × 10 −4 to 1.7-2.9 × 10 −4 unit/10 6 cells. When the amplified GS-CHO cells were cultured in the ammonia-containing medium, a slow but steady decrease of the ammonia level was observed when the level was high. Finally, the prospect of genetically modulated cells for bioreactors in the hybrid artificial liver is discussed.

Flux distributions in anaerobic, glucose-limited continuous cultures of Saccharomyces cerevisiae.

A stoichiometric model describing the anaerobic metabolism of Saccharomyces cerevisiae during growth on a defined medium was derived. The model was used to calculate intracellular fluxes based on measurements of the uptake of substrates from the medium, the secretion of products from the cells, and of the rate of biomass formation. Furthermore, measurements of the biomass composition and of the activity of key enzymes were used in the calculations. The stoichiometric network consists of 37 pathway reactions involving 43 compounds of which 13 were measured (acetate, CO2, ethanol, glucose, glycerol, NH4+, pyruvate, succinate, carbohydrates, DNA, lipids, proteins and RNA). The model was used to calculate the production rates of malate and fumarate and the ethanol measurement was used to validate the model. All rate measurements were performed on glucose-limited continuous cultures in a high-performance bioreactor. Carbon balances closed within 98%. The calculations comprised flux distributions at specific growth rates of 0.10 and 0.30 h-1. The fluxes through reactions located around important branch points of the metabolism were compared, i.e. the split between the pentose phosphate and the Embden-Meyerhoff-Parnas pathways. Also the model was used to show the probable existence of a redox shunt across the inner mitochondrial membrane consisting of the reactions catalysed by the mitochondrial and the cytosolic alcohol dehydrogenase. Finally it was concluded that cytosolic isocitrate dehydrogenase is probably not present during growth on glucose. The importance of basing the flux analysis on accurate measurements was demonstrated through a sensitivity analysis. It was found that the accuracy of the measurements of CO2, ethanol, glucose, glycerol and protein was critical for the correct calculation of the flux distribution.

Wastewater treatment in a biological high-performance system with high biomass concentration

The influence of high biomass concentration on the operating conditions of a newly developed high-performance bioreactor, the impinging-stream loop reactor, combined with membrane filtration is discussed. The efficiency and the advantages of this combination with respect to economy, effluent concentration and operating conditions are shown in comparison to conventional wastewater treatment plants. Finally, a short summary of investigations with a pilot plant for treatment of landfill leachate are given.

Automatic bioprocess control. 3. Impacts on process perception

Impacts of a careful and extensive process control are shown by a fully automated repetitive batch culture of Saccharomyces cerevisiae grown on defined medium. The equipment consists of a high performance bioreactor with three different computerized controllers and is designed for complex, demanding tasks. It is demonstrated that the advantages of this approach are manifold for scientists as well as engineers. The high degree of automation increases the availability of the equipment and improves bioprocess accomplishment substantially. Results on the excellent reproducibility of biotechnological experiments underline the new quality of this concept and make the benefits for fundamental scientific work and process development obvious. A powerful software is of decisive importance for processing the extent of raw data produced during high resolution process monitoring. Examples for online process identification are given.