Scaled-up System Research Articles

Analysis of green algal growth via dynamic model simulation and process optimization.

Chlamydomonas reinhardtii is a green microalga with the potential to generate sustainable biofuels for the future. Process simulation models are required to predict the impact of laboratory-scale growth experiments on future scaled-up system operation. Two dynamic models were constructed to simulate C. reinhardtii photo-autotrophic and photo-mixotrophic growth. A novel parameter estimation methodology was applied to determine the values of key parameters in both models, which were then verified using experimental results. The photo-mixotrophic model was used to accurately predict C. reinhardtii growth under different light intensities and in different photobioreactor configurations. The optimal dissolved CO2 concentration for C. reinhardtii photo-autotrophic growth was determined to be 0.0643 g·L(-1) , and the optimal light intensity for algal growth was 47 W·m(-2) . Sensitivity analysis revealed that the primary factor limiting C. reinhardtii growth was its intrinsic cell decay rate rather than light attenuation, regardless of the growth mode. The photo-mixotrophic growth model was also applied to predict the maximum biomass concentration at different flat-plate photobioreactors scales. A double-exposure-surface photobioreactor with a lower light intensity (less than 50 W·m(-2) ) was the best configuration for scaled-up C. reinhardtii cultivation. Three different short-term (30-day) C. reinhardtii photo-mixotrophic cultivation processes were simulated and optimised. The maximum biomass productivity was 0.053 g·L(-1) ·hr(-1) , achieved under continuous photobioreactor operation. The continuous stirred-tank reactor was the best operating mode, as it provides both the highest biomass productivity and lowest electricity cost of pump operation.

Serum-Free Directed Differentiation of Human Embryonic Stem Cells to Hepatocytes.

The increase in human liver disease worldwide is a major concern. At present, the only successful mode of treatment for failing liver function is organ transplantation. While highly successful, donor organs are a limited resource that cannot meet current demands. Therefore, alternative liver support strategies have been explored, including the use of the major and metabolic cell within the liver, the hepatocyte. While current approaches using human hepatocytes are very promising, donor material is still required and therefore suffers from similar limitations to whole organ transplantation. One alternative source of human hepatocytes being actively pursued in the field is pluripotent stem cells. Pluripotent stem cells are a scalable and renewable cell-based resource, which can be efficiently differentiated towards hepatocytes, including pluripotent stem cell lines that have been derived under good manufacturing practice conditions. Therefore, it is believed that this approach provides a promising model system for cell scale-up and differentiation. In the future, pluripotent stem cell-derived hepatocytes could be used in the clinic to support failing liver function if they should be deemed fit for purpose.

Development of a Modeling-Based Strategy for the Safe and Effective Scale-up of Highly Energetic Hydrogenation Reactions

A modeling-based strategy is disclosed for identifying reaction conditions for the safe and effective scale-up of highly energetic hydrogenation reactions. The model was developed within Scale-up Systems’s DynoChem 2011 and takes under consideration the kinetics of the reaction, the reactor heat transfer capabilities, and the degree of mass transfer. Fourier transform infrared spectroscopy (FT-IR), heat flow, and H2 uptake data were used to determine the reaction kinetics that were found to be most accurately described by a Langmuir–Hinshelwood type model. The scale-up model was validated within our kilo-laboratory using a 5 L reactor.

Scale-up analysis of continuous cross-flow atomic layer deposition reactor designs

This paper presents the development of a non-dimensional model of a continuous cross-flow atomic layer deposition (ALD) reactor with temporally separated precursor pulsing and a structured model-based methodology for scaling up the substrate dimensions. The model incorporates an ALD gas–surface reaction kinetic mechanism for the deposition of thin ZnO films from Zn(C2H5)2 and H2O precursors that was experimentally validated in our previous work (Holmqvist et al., 2012, 2013a). In order to maintain dynamic similarity, a scaling analysis was applied based on the dimensionless numbers, appearing in non-dimensionalized momentum and species mass conservation equations, that describe the convective laminar flow, mass transfer and heterogeneous reaction. The impact on these dimensionless numbers and, more importantly, the impact on the limit-cycle deposition rate and its relative uniformity was thoroughly investigated when linearly scaling up the substrate dimensions. In the scale-up procedure, the limit-cycle precursor utilization was maximized by means of dynamic optimization, while ensuring that identical deposition profiles were obtained in the scaled-up system. The results presented here demonstrated that the maximum precursor yields were promoted at higher substrate dimensions. Limit-cycle dynamic solutions to the non-dimensionalized model, computed with a collocation discretization in time, revealed that it is a combination of the degree of precursor depletion in the flow direction and the magnitude of the pressure drop across the reactor chamber that governs the extent of the deposition profile non-uniformity. A key finding of this study is the identification of optimal scaling rules for maximizing precursor utilization in the scaled-up system while maintaining fixed absolute growth rate and its relative uniformity.

Comparative study of the kinetic approach on the alcoholic fermentation procedure conducted in laboratory and scale-up systems by inverse gas chromatography

Summary The major objective of the present work was to compare the kinetic study of alcoholic fermentations conducted in the presence of wheat supported biocatalysts in laboratory scale and in a scale-up system of 80 L and to compare these results with those reported in literature. The kinetic study of fermentation processes was accomplished with the technique of reversed flow gas chromatography (RFGC), which is a version of inverse gas chromatography. The wine yeast species used was Saccharomyces cerevisiae AXAZ-1, and fermentations were conducted between 20 and 2°C. At low temperatures, maximal ethanol productivity and fermentation rate were reduced. The rate constants, determined through a mathematical model obtained from RFGC, were higher in the laboratory scale comparing to the scale-up system at the temperatures of 20 and 15°C. However, with the reduction of temperature, both systems presented almost similar values proving the great fermentative ability of immobilized cells even at extremely low tem...

Process Scale-Up Systems from 100mL to 200L

Process Scale-Up Systems from 100mL to 200L

New fabrication of mixed oxygen carrier for CLC: Sludge and scale from a power plant

After successful operation of a 200kW gas circulating combustion system for over 100h with NiO/Al2O3 oxygen carrier (OC) particles, we are ready to scale-up the process up to a 1–10MW system. To supply large quantity of OC particles for the scaled-up system at a lower cost, iron oxides are considered as a cheaper source material of OC. Mixed NiO/Fe2O3/Al2O3 OC particles were fabricated with commercial iron oxide reagents by a spray-dryer and tested for oxygen transfer capacity (OTC) and physical/chemical properties to investigate the feasibility of mass production. While looking for cheap iron oxides from wastes or industrial products, considerable amounts of scale and sludge were found from power plants. The main component of the sludge and scale collected from power plants was more than 95% of iron oxides and the residue was also oxides, such as MnO, SiO2, Cr2O3 and CaO, which can be an active material or a binder for OC. The particle size of the sludge and scale is also suitable for the OC fabrication, eliminating the need of pre-treatment. Four different OC particles were fabricated by a spray-dryer, calcined at 1100, 1200 and 1300°C, and their physical/chemical properties were measured. It was found that mixed NiO/Fe2O3/Al2O3 oxide carriers are good candidates for a 1–10MW class circulation combustion of fluidized bed. The contribution of this research is that the sludge and scale collected from power plants can be used to capture CO2 emitted from power plants.

Extruder scale-up assessment in the process of extrusion–spheronization: comparison of radial and axial systems by a design of experiments approach

Scaling-up the extrusion–spheronization process involves the separate scale-up of each of the five process steps: dry mixing, granulation, extrusion, spheronization, and drying. The aim of the study was to compare two screw extrusion systems regarding their suitability for scaling-up. Two drug substances of high- and low-solubility in water were retained at different concentrations as formulation variables. Different spheronization times were tested. The productivity of the process was followed up using the extrusion rate and yield. Pellets were characterized by their size and shape, and by their structural and mechanical properties. A response surface design of experiments was built to evaluate the influence of the different variables and their interactions on each response, and to select the type of extrusion which provides the best results in terms of product quality, the one which shows less influence on the product after scale-up (“scalability”) and when the formula used changes (“robustness”), and the one which allows the possibility to adjust pellet properties with spheronization variables (“flexibility”). Axial system showed the best characteristics in terms of product quality at lab and industrial scales, the best robustness at industrial scale, and the best scalability, by comparison with radial system. Axial system thus appeared as the easiest scaled-up system. Compared to lab scale, the conclusions observed at industrial scale were the same in terms of product quality, but different for robustness and flexibility, which confirmed the importance to test the systems at industrial scale before acquiring the equipment.

Removing of Nano-Particles from Semiconductor Wastewater Using a Hybrid Treatment System

Packaging process is one of the main manufacturing steps in the wafer fabrication industries. However, nano-particles would be produced during the packaging process. The produced nano-particle-contained wastewater has characteristics of dark color and high turbidity. Because the nano-particles would usually result in the clogging of the membrane filtration system when it is used for water treatment and reclamation, the application of a pre-treatment system is required to extend the membrane life. The objective of this study was to develop a pre-treatment system for packaging wastewater treatment before membrane system was applied for further water quality improvement. In this laboratory-scale study, a hybrid treatment system containing a chemical coagulation/flocculation followed by ultra-filtration (UF) membrane technology was developed for the wafer fabrication wastewater treatment. The chemical coagulation/flocculation unit was used as the pre-treatment process to improve the efficiency of the following ultra-filtration (UF) membrane system. The packaging wastewater was collected from a wafer fabrication factory and used to evaluate the feasibility of the coagulation/flocculation process on nano-scale particle removal. Results show that approximately 98% of turbidity could be removed at pH 7 when 2.2 mg/L of polyaluminum chloride (PAC) (used as coagulant) and 0.5 mg/L of polyacrylamide (cPAM) (used as flocculant) were added during the coagulation/flocculation process. Results indicate that the coagulation/flocculation is a feasible pre-treatment process for nano-particle removal before UF membrane is applied for further water purification. Results from this study will be helpful in designing a scale-up system for practical applications.

Optimization of fatty alcohol biosynthesis pathway for selectively enhanced production of C12/14 and C16/18 fatty alcohols in engineered Escherichia coli

BackgroundWith the increasing stress from oil price and environmental pollution, aroused attention has been paid to the microbial production of chemicals from renewable sources. The C12/14 and C16/18 alcohols are important feedstocks for the production of surfactants and detergents, which are widely used in the most respected consumer detergents, cleaning products and personal care products worldwide. Though bioproduction of fatty alcohols has been carried out in engineered E. coli, several key problems have not been solved in earlier studies, such as the quite low production of C16/18 alcohol, the lack of optimization of the fatty alcohol biosynthesis pathway, and the uncharacterized performance of the engineered strains in scaled-up system.ResultsWe improved the fatty alcohol production by systematically optimizing the fatty alcohol biosynthesis pathway, mainly targeting three key steps from fatty acyl-acyl carrier proteins (ACPs) to fatty alcohols, which are sequentially catalyzed by thioesterase, acyl-coenzyme A (CoA) synthase and fatty acyl-CoA reductase. By coexpression of thioesterase gene BTE, acyl-CoA synthase gene fadD and fatty acyl-CoA reductase gene acr1, 210.1 mg/L C12/14 alcohol was obtained. A further optimization of expression level of BTE, fadD and acr1 increased the C12/14 alcohol production to 449.2 mg/L, accounting for 75.0% of the total fatty alcohol production (598.6 mg/L). In addition, by coexpression of thioesterase gene ‘tesA, acyl-CoA synthase gene fadD and fatty acyl-CoA reductase gene FAR, 101.5 mg/L C16/18 alcohol was obtained, with C16/18 alcohol accounting for 89.2% of the total fatty alcohol production.ConclusionsTo our knowledge, this is the first report on selective production of C12/14 and C16/18 alcohols by microbial fermentation. This work achieved high-specificity production of both C12/14 and C16/18 alcohols. The encouraging 598.6 mg/L of fatty alcohols represents the highest titer reported so far. In addition, the 101.5 mg/L 89.2% C16/18 alcohol suggests an important breakthrough in C16/18 alcohol production. A more detailed optimization of the expression level of fatty alcohol biosynthesis pathway may contribute to a further improvement of fatty alcohol production.

A scaled‐up system to evaluate zooplankton spatial avoidance and the population immediate decline concentration

Most laboratory tests may underestimate adverse effects in real scenarios of contamination because they imply the forced exposure of organisms to contaminants, thus overlooking the possibility of emigration. Avoidance from contaminants has been observed in several aquatic organisms, and avoidance-based tests have been recommended to be included in risk assessment studies. To reduce uncertainty in the extrapolation of laboratory derived results, the first aim of the present study was to compare both the median avoidance concentration and the lowest-observed-effect gradient (LOEG) values of atrazine for the cladoceran Daphnia magna, between an already developed 1.1-m-long system and a scaled-up system, three times longer. Second, the present study aimed at evaluating the population immediate decline--the proportion of the population that disappears (avoids and, if not, dies)--through the integration of the relationships between lethality and avoidance versus contaminant concentration. Daphnia magna significantly avoided atrazine, during 12-h exposures, with similar results in the original and scaled-up systems. The population immediate decline at the 48-h median lethal concentration would be 94%. Even at a concentration eliciting only 5% mortality, the population immediate decline would be over 50%. Achieving a higher pertinence of avoidance results and a better understanding of the LOEG values and their time dependence, scaling up the system further both spatially and temporally, and modeling explicit spatial dynamics in exposure and organism movement in space and time are needed.

Technical Note: Feasibility of Extracting Ammonia from Broiler Litter and Scale-Up Considerations

Air inside the broiler litter bed has high ammonia concentrations. The feasibility of extracting ammonia from the broiler litter bed for use as a fertilizer was investigated. Suction was applied to six -in. (12.7-mm) CPVC pipes with perforations placed 0.15 m below the litter surface in a pen stocked with 150 birds. Litter air was pulled into a phosphoric acid reactor where the ammonia was converted to ammonium phosphate, a fertilizer. Over 51 d, 72.6 g of ammonia was recovered and the pipes did not clog. Ammonia recovery could have been higher had litter ammonia concentrations been comparable with commercial broiler houses. Ammonia removal from the pen did not impact ammonia concentrations above the litter or bird performance. Placing the pipes close to the litter surface where total ammoniacal nitrogen concentrations would have been higher due to fecal loading may have reduced ammonia concentrations in the pen. Litter moisture content was reduced by the ammonia extraction system. A modified scaled-up system may be technically feasible but not cost-effective. Economic feasibility of the system can be improved if pipes placed closer to the surface improve bird performance by reducing in-house ammonia concentrations.

Efficacy of washing with hydrogen peroxide followed by aerosolized antimicrobials as a novel sanitizing process to inactivate Escherichia coli O157:H7 on baby spinach

Aerosolization was investigated as a potential way to apply allyl isothiocyanate (AIT), hydrogen peroxide (H(2)O(2)), acetic acid (AA) and lactic acid (LA) on fresh baby spinach to control Escherichia coli O157:H7 during refrigeration storage. In this study, baby spinach leaves were dip-inoculated with E. coli O157:H7 to a level of 6 log CFU/g and stored at 4°C for 24 h before treatment. Antimicrobials were atomized into fog-like micro-particles by an ultrasonic nebulizer and routed into a jar and a scale-up model system where samples were treated. Samples were stored at 4°C for up to 10 days before the survival of the cells was determined. A 2-min treatment with 5% AIT resulted in a >5-log reduction of E. coli O157:H7 on spinach after 2 days refrigeration regardless if the samples were pre-washed or not; however, this treatment impaired the sensory quality of leaves. Addition of LA to AIT improved the antimicrobial efficacy of AIT. In the jar system, washing with 3% H(2)O(2) followed by a 2-min treatment of 2.5% LA+1% AIT or 2.5% LA+2% AIT reduced E. coli O157:H7 population by 4.7 and >5 log CFU/g, respectively, after 10 days refrigeration. In the scale-up system, up to 4-log reduction of bacterial population was achieved for the same treatments without causing noticeable adverse effect on the appearance of leaves. Thus, this study demonstrates the potential of aerosolized AIT+LA as a new post-washing intervention strategy to control E. coli O157:H7 on baby spinach during refrigeration storage.

Application of <i>In Situ</i> Chemical Oxidation for the Remediation of TPH-Contaminated Soils

Soils at many existing and former industrial areas and disposal sites are contaminated by petroleum hydrocarbons. In this study, laboratory bench-scale experiments were performed to evaluate the effectiveness of applying in situ chemical oxidation (ISCO) on the treatment of petroleum-hydrocarbon contaminated soils. Three different oxidation processes including Fenton’s oxidation, persulfate oxidation, and permanganate oxidation were evaluated with initial total petroleum hydrocarbon (TPH) concentration of approximately 3,920 mg/kg. The major control factors were oxidant species (hydrogen peroxide, persulfate, permanganate) and soil to liquid volume ratios (1 to 3). The oxidant concentration was 5 wt.%. Ferrous iron was used as the catalyst during the Fenton’s oxidation and persulfate oxidation processes, and the oxidant to ferrous iron molar ratio was 1 to 0.1. Among these three oxidation processes, contaminated soils treated by permanganate oxidation had the highest TPH removal efficiency (94% of TPH removal) during 360 min of operation. Approximately 75 and 61% of TPH removal was observed in batch experiments applying Fenton’s oxidation and persulfate oxidation, respectively. Due to the consumption of ferrous iron (used as the catalytic chemical) in the early stage during the operational period, both persulfate and Fenton’s oxidation processes had less TPH removal efficiencies. Frequent supplement of catalyst is required when persulfate and Fenton’s oxidation is applied for field application. Results from this study indicate that the ISCO scheme is a feasible technology for the treatment of petroleum-hydrocarbon contaminated soils within a short treatment period. The experimental results can be used for a scale-up system for practical application.

Effects of cultural medium and conditions on the proliferation and hypoglycemic activity of Saccharomyces pastorianus no. 54

A yeast strain of Saccharomyces pastorianus no. 54 with hypoglycemic activity was isolated from soils of a winery. The aims of this study were first to investigate the effects of the cultivation conditions on proliferation and hypoglycemic activity of this yeast using the assay model of the differentiated 3T3-L1 adipocytes, and then, to confirm in vivo the hypoglycemic activity of cultured yeast by oral administration in streptozotocin (STZ)-induced diabetic mice. Among 7 diluted fruit juice samples the diluted strawberry juice (1.74 g/L reducing sugar content) was chosen as the basal medium. After investigation of the effects of addition of various substances, including 1% of 5 different sugars and glycerol, 0.1% of 6 nitrogen-containing substances, and 1 ppm of 7 growth factors, the diluted strawberry juice added with 1% glucose, 0.1% yeast extract and 1 ppm aspartic acid was optimized at 20 °C with initial pH value of 6.0 for cultivating S. pastorianus no. 54 in flask. The scale-up system of a 5-L fermentor was further established by using the same medium with initial pH 6.0 and being incubated at 20 °C with an aeration rate of 1.2 vvm for 96 h. The hypoglycemic activity of yeast cells cultivated in fermentor was 3.11 times of that in flask. Oral administration of the cultured yeast at a dosage of 130 mg/kg body weight/day for 6 days could significantly reduce the plasma glucose content in STZ-induced diabetic mice and keep their body weights in the normal range.

In situ oxidation of petroleum-hydrocarbon contaminated groundwater using passive ISCO system

Groundwater contamination by gasoline spill is a worldwide environmental problem. Gasoline contains methyl tertiary-butyl ether (MTBE) (a fuel oxygenates) and benzene, which are the chemicals of concerns among the gasoline components. In this study, an in situ chemical oxidation (ISCO) barrier system was developed to evaluate the feasibility of applying this passive system on the control of MTBE and benzene plume in aquifer. The developed ISCO barrier contained oxidant-releasing materials, which could release oxidants (e.g., persulfate) when contact with water for the contaminants’ oxidation in groundwater. In this study, laboratory-scale fill-and-draw experiments were conducted to determine the component ratios of the oxidant-releasing materials and evaluate the persulfate release rates. Results indicate that the average persulfate-releasing rate of 7.26 mg S 2O 8 2−/d/g was obtained when the mass ratio of sodium persulfate/cement/sand/water was 1/1.4/0.24/0.7. The column study was conducted to evaluate the efficiency of in situ application of the developed ISCO barrier system on MTBE and benzene oxidation. Results from the column study indicate that approximately 86–92% of MTBE and 95–99% of benzene could be removed during the early persulfate-releasing stage (before 48 pore volumes of groundwater pumping). The removal efficiencies for MTBE and benzene dropped to approximately 40–56% and 85–93%, respectively, during the latter part of the releasing period due to the decreased persulfate-releasing rate. Results reveal that acetone, byproduct of MTBE, was observed and then further oxidized completely. Results suggest that the addition of ferrous ion would activate the persulfate oxidation. However, excess ferrous ion would compete with organic contaminants for persulfate, and thus, cause the decrease in contaminant oxidation rates. The proposed treatment scheme would be expected to provide a more cost-effective alternative to remediate MTBE, benzene, and other petroleum-hydrocarbon contaminated aquifers. Results from this study will be useful in designing a scale-up system for field application.

Studies on the electrochemical disinfection of water containing Escherichia coli using a Dimensionally Stable Anode

The aim of this work was to investigate the disinfectant effect of electrolysis on chlorine-free water, artificially contaminated with Escherichia coli (CCT-1457) and to evaluate the bactericidal activity of electrolysis and kinetic behavior of a single-cell reactor, with a DSA (Dimensionally Stable Anode) electrode to develop a scaled-up system. A high-density E. coli suspension (10(6) CFU mL-1) was electrolyzed in this reactor at 25, 50 and 75 mA cm-2 for up to 60 min, at flow rates of 200 and 500 L h-1. Bacterial survival fell by 98.9% without addition of chlorinated compounds and a power consumption rate not more than 5.60 kWh m-3 at flow rate of 200 L h-1 and 75 mA cm-2. The process produced a germicidal effect that reached this inactivation rate within a relatively short contact time. Also, a solution of electrolyzed 0.08 M Na2SO4 added to the inoculum showed residual bactericidal effect. The efficiency of disinfection was regulated by both the contact time and current density applied, and a kinetic function for the survival rate was developed for the purpose of scaling up.

Performance of an adiabatic cross-flow liquid-desiccant absorber inside a refrigerated warehouse

Liquid-desiccant systems have been extensively studied as a way of reducing the latent load on air conditioning systems. Most of the studies have targeted the removal of moisture from air at ambient conditions. The literature about the use of liquid desiccants in low temperature applications is scarce. In this study, a small-scale liquid-desiccant absorber is installed inside a commercial refrigerated warehouse. Its performance under realistic operating conditions inside a pre-cooling room is analyzed. The results show that the dew point temperature of the air downstream of the absorber is comparable to the evaporator surface temperature suggesting the potential to delay the formation of ice on the cooling coil. An internal heat exchanger is used to lower the temperature of the inlet liquid-desiccant flow to the absorber and the regeneration process is performed using only ambient air. The analysis of the reduction in water and energy consumption for a scaled-up system is also performed.

Scale-up of extremely low temperature fermentations of grape must by wheat supported yeast cells

A new biocatalyst was prepared by immobilization of Saccharomyces cerevisiae AXAZ-1 yeast cells on whole wheat grains. This biocatalyst was used for 30 repeated batch fermentations of glucose and grape must at various temperatures. The biocatalyst retained its operational stability for a long period and it was proved capable to produce dry wines of fine clarity even at extremely low temperatures (5 °C). After the completion of these fermentations the new biocatalyst was used in a scale-up system of 80 L for wine making at ambient (20 °C) and extremely low temperatures (2 °C). The scale-up process did not affect the fermentative ability of biocatalyst, even at low temperatures, while the produced wines had almost the same improved aromatic profile compare to free cells as revealed by GC and GC–MS analyses. More specifically the results showed that both systems with immobilized cells (laboratory scale and 80 L bioreactor) increased the formation of esters and produced wines with improved aromatic profile compared to those with free cells. Finally an increase in the percentages of total esters and a decrease in those of higher alcohols was observed in lower fermentation temperatures.

Extraction and characterization of polygalacturonase of Fomes sclerodermeus produced by solid-state fermentation.

Polygalacturonase (PG) production by Fomes sclerodermeus using solid-state fermentation (SSF) was carried out. Maximal PG activity (26 U/gdw) was obtained between days 11 and 13 at the end of exponential growth. PG activity in the crude extract was more stable at pH 5-6 and 30 degrees C and had optimum activity at pH 5 and 50 degrees C. Optimal conditions for PG extraction were: one time extraction with Na2SO4 as solvent with 10 min. of agitation. In a scale-up system, PG activity per gram of dry substrate decreased about 60% compared with the activity obtained in an Erlenmeyer flask; however, high total PG activity was obtained.