Showing papers on "Bioreactor published in 2010"
TL;DR: Protein and lipids content analysis suggest that, from a practical point of view, immobilized systems could facilitate the separation of the biomass from the treated wastewater although in terms of nutritional value of the microalgae, immobilization systems do not represent an advantage over free-cell systems.
577 citations
TL;DR: In this article, an overview of the practical implementation of autotrophic nitrogen removal is presented, and the different nitrogen removal processes are compared in terms of operational conditions and a direction for future work is provided.
498 citations
TL;DR: The oxygen uptake rate (THE AUTHORS') in different fermentation broths is examined and the reciprocal influence of THEIR and OTR is presented and an analysis of rate-limiting variables is carried out.
376 citations
TL;DR: The occurrence and elimination of 19 micro-organic pollutants including endocrine disrupting chemicals and pharmaceuticals and personal care products in a full-scale anaerobic/anoxic/aerobic-membrane bioreactor process was investigated and it was found that the fast sludge adsorption is responsible for the rapid decline of the aqueous concentration of the targets in the first compartment of the treatment process.
221 citations
TL;DR: The results of both analytical methods confirm the presence of anaerobic ammonium oxidizing bacteria as the predominant species along with other Planctomycete-like bacteria and offer the simultaneous removals of nitrogen and COD in the wastewater.
219 citations
TL;DR: It is demonstrated that it is feasible to form aerobic granules in pilot-scale SBR reactor and maintain the long-term stability of granular sludge with a high influent quality fluctuation and stable COD and NH4(+)-N removal efficiencies can be obtained in the reactor.
198 citations
TL;DR: Biological nutrient removal was investigated in a sequencing batch membrane bioreactor which used carriers instead of activated sludge and results of microbes showed the composition and spatial structure of the microbial community in the reactor.
172 citations
TL;DR: This study shows that the sequenced Pseudomonas aeruginosa strain PAO1 is able to produce high quantities of rhamnolipid during 30 L batch bioreactor cultivations with sunflower oil as sole carbon source and nitrogen limiting conditions, and surprisingly has the potential as a strain of choice for actual biotechnological rhamNolipids production.
Abstract: Rhamnolipids are biosurfactants with interesting physico-chemical properties. However, the main obstacles towards an economic production are low productivity, high raw-material costs, relatively expensive downstream processing, and a lack of understanding the rhamnolipid production regulation in bioreactor systems. This study shows that the sequenced Pseudomonas aeruginosa strain PAO1 is able to produce high quantities of rhamnolipid during 30 L batch bioreactor cultivations with sunflower oil as sole carbon source and nitrogen limiting conditions. Thus PAO1 could be an appropriate model for rhamnolipid production in pilot plant bioreactor systems. In contrast to well-established production strains, PAO1 allows knowledge-based systems biotechnological process development combined with the frequently used heuristic bioengineering approach. The maximum rhamnolipid concentration obtained was 39 g/L after 90 h of cultivation. The volumetric productivity of 0.43 g/Lh was comparable with previous described production strains. The specific rhamnolipid productivity showed a maximum between 40 and 70 h of process time of 0.088 gRL/gBDMh. At the same time interval, a shift of the molar di- to mono-rhamnolipid ratio from 1:1 to about 2:1 was observed. PAO1 not only seems to be an appropriate model, but surprisingly has the potential as a strain of choice for actual biotechnological rhamnolipid production.
163 citations
TL;DR: The results show that sponge thickness deteriorated the organic and nutrient removal and 1cm is the optimum thickness for fixed-bed sponge biofilter (SBF); sponge volume had significant impact on phosphorus removal rather than organic or nitrogen removal.
147 citations
TL;DR: PAS grown granular sludges showed an important increase in particle size during the operation of the UASB reactors and addition of 1gCa(2+)/L to the high salinity wastewater increases the granules' strength.
138 citations
TL;DR: Granular sludge could be developed in a single reactor with an intermittent anaerobic-aerobic reaction phase and is capable in treating the textile wastewater and demonstrated good removal of COD and ammonia.
TL;DR: L Laboratory biodegradation experiments on sub-bituminous coal from Texas, USA, were conducted using bioreactors to examine the organic intermediates relevant to methane production, and production of methane in the bioreacts was linked to acetate accumulation in bioreactor fluid.
TL;DR: The results of this study could be used for a better design, shorter start-up time, and more stable operation of anammox systems for the treatment of nitrogen-rich wastewaters.
Abstract: Anaerobic ammonium oxidation (anammox) is a promising new process to treat high-strength nitrogenous wastewater. Due to the low growth rate of anaerobic ammonium-oxidizing bacteria, efficient biomass retention is essential for reactor operation. Therefore, we studied the settling ability and community composition of the anaerobic ammonium-oxidizing granules, which were cultivated in an upflow anaerobic sludge blanket (UASB) reactor seeded with aerobic granules. With this seed, the start-up period was less than 160 days at a NH4+-N removal efficiency of 94% and a loading rate of 0.064 kg N per kg volatile suspended solids per day. The formed granules were bright red and had a high settling velocity (41 to 79 m h−1). Cells and extracellular polymeric substances were evenly distributed over the anaerobic ammonium-oxidizing granules. The high percentage of anaerobic ammonium-oxidizing bacteria in the granules could be visualized by fluorescent in situ hybridization and electron microscopy. The copy numbers of 16S rRNA genes of anaerobic ammonium-oxidizing bacteria in the granules were determined to be 4.6 × 108 copies ml−1. The results of this study could be used for a better design, shorter start-up time, and more stable operation of anammox systems for the treatment of nitrogen-rich wastewaters.
TL;DR: Rocking-motion-type bioreactors may provide an interesting alternative to standard cultivation in bioreacts for cultivation of bacteria and recombinant protein production and internal substrate delivery systems such as EnBase® Flo provide an opportunity for adopting simple to use fed-batch-type strategies to shaken cultures.
Abstract: Single-use rocking-motion-type bag bioreactors provide advantages compared to standard stirred tank bioreactors by decreased contamination risks, reduction of cleaning and sterilization time, lower investment costs, and simple and cheaper validation. Currently, they are widely used for cell cultures although their use for small and medium scale production of recombinant proteins with microbial hosts might be very attractive. However, the utilization of rocking- or wave-induced motion-type bioreactors for fast growing aerobic microbes is limited because of their lower oxygen mass transfer rate. A conventional approach to reduce the oxygen demand of a culture is the fed-batch technology. New developments, such as the BIOSTAT® CultiBag RM system pave the way for applying advanced fed-batch control strategies also in rocking-motion-type bioreactors. Alternatively, internal substrate delivery systems such as EnBase® Flo provide an opportunity for adopting simple to use fed-batch-type strategies to shaken cultures. Here, we investigate the possibilities which both strategies offer in view of high cell density cultivation of E. coli and recombinant protein production. Cultivation of E. coli in the BIOSTAT® CultiBag RM system in a conventional batch mode without control yielded an optical density (OD600) of 3 to 4 which is comparable to shake flasks. The culture runs into oxygen limitation. In a glucose limited fed-batch culture with an exponential feed and oxygen pulsing, the culture grew fully aerobically to an OD600 of 60 (20 g L-1 cell dry weight). By the use of an internal controlled glucose delivery system, EnBase® Flo, OD600 of 30 (10 g L-1 cell dry weight) is obtained without the demand of computer controlled external nutrient supply. EnBase® Flo also worked well in the CultiBag RM system with a recombinant E. coli RB791 strain expressing a heterologous alcohol dehydrogenase (ADH) to very high levels, indicating that the enzyme based feed supply strategy functions well for recombinant protein production also in a rocking-motion-type bioreactor. Rocking-motion-type bioreactors may provide an interesting alternative to standard cultivation in bioreactors for cultivation of bacteria and recombinant protein production. The BIOSTAT® Cultibag RM system with the single-use sensors and advanced control system paves the way for the fed-batch technology also to rocking-motion-type bioreactors. It is possible to reach cell densities which are far above shake flasks and typical for stirred tank reactors with the improved oxygen transfer rate. For more simple applications the EnBase® Flo method offers an easy and robust solution for rocking-motion-systems which do not have such advanced control possibilities.
TL;DR: Based on batch assays, hydrazine oxidoreductase expression and concentrations of the 16S-23S rRNA intergenic spacer region (ISR) were good quantitative biomarkers of oxygen- and nitrite-mediated inhibition and both molecular biomarkers show promise as monitoring tools for "predicting" reactor performance.
Abstract: Anaerobic ammonium oxidation (anammox) requires 60% less oxygen and no external organic carbon compared to conventional biological nitrogen removal (BNR) Nevertheless, full-scale installations of anammox are uncommon, primarily owing to the lack of well-established process monitoring and control strategies that result in stable anammox reactor performance The overarching goal of this study was to develop and apply molecular biomarkers that link microbial community structure and activity to anammox process performance in a bioreactor fed with actual anaerobic digestion centrate from a full-scale operational wastewater treatment facility Over long-term operation, Candidatus "Brocadia sp 40" emerged as the dominant anammox population present in the reactor There was good correspondence between reactor nitrogen removal performance and anammox bacterial concentrations During the period of reactor operation, there was also a marked shift in biomass morphology from discrete cells to granular aggregates, which was paralleled by a shift also to more stable nitrogen removal and the succession and establishment of bacteria related to the Chlorobi/Bacteroidetes superfamily Based on batch assays, hydrazine oxidoreductase (hzo) expression and concentrations of the 16S-23S rRNA intergenic spacer region (ISR) were good quantitative biomarkers of oxygen- and nitrite-mediated inhibition When applied to a continuous anammox reactor, both molecular biomarkers show promise as monitoring tools for "predicting" reactor performance
TL;DR: The submerged anaerobic membrane biological reactor (KSAMBR) as mentioned in this paper was developed in the last decade and successfully applied in a number of full-scale food and beverage industries.
TL;DR: This work describes for the first time the use of bubbleless bioreactors for the production of these lipopeptides by B. subtilis ATCC 21332 with aeration by a hollow fiber membrane air–liquid contactor to prevent foam formation.
Abstract: Surfactin and fengycin are lipopeptide biosurfactants produced by Bacillus subtilis. This work describes for the first time the use of bubbleless bioreactors for the production of these lipopeptides by B. subtilis ATCC 21332 with aeration by a hollow fiber membrane air–liquid contactor to prevent foam formation. Three different configurations were tested: external aeration module made from either polyethersulfone (reactor BB1) or polypropylene (reactor BB2) and a submerged module in polypropylene (reactor BB3). Bacterial growth, glucose consumption, lipopeptide production, and oxygen uptake rate were monitored during the culture in the bioreactors. For all the tested membranes, the bioreactors were of satisfactory bacterial growth and lipopeptide production. In the three configurations, surfactin production related to the culture volume was in the same range: 242, 230, and 188 mg l−1 for BB1, BB2, and BB3, respectively. Interestingly, high differences were observed for fengycin production: 47 mg l−1 for BB1, 207 mg l−1 for BB2, and 393 mg l−1 for BB3. A significant proportion of surfactin was adsorbed on the membranes and reduced the volumetric oxygen mass transfer coefficient. The degree of adsorption depended on both the material and the structure of the membrane and was higher with the submerged polypropylene membrane.
TL;DR: This study proved that photosynthetic bacteria could transform complex wastewater that contains recalcitrant organic compounds with a resultant recovery of useful products.
Abstract: A suspended growth photobioreactor was utilized to treat pharmaceutical wastewater by a wild strain purple non-sulfur photosynthetic bacterium isolated from the soil. The strain was named Z08 and identified as Rhodobacter-sphaeroides by 16SrDN. The photobioreactor was illuminated externally with two (40 W) fluorescent compact light sources on both sides. Its operation pH and temperature were between 6.8 - 7.0 and 20 - 30 oC, respectively. Optimum growth of the isolate was obtained after enrichment of the pharmaceutical wastewater with 0.5 % ammonium sulfate and 0.1 % yeast extract under microaerobic optimum light (6000 lx) condition at 5d retention. Using these optimum conditions, the maximum dry cell weight and chemical oxygen demand percentage removal were 880 mg/L and 80 %. Chemical analysis of the culture after treatment of the enriched and non-enriched wastewater showed the crude protein content of the biomass to be 54.6 % and 38.0 %, respectively. This study proved that photosynthetic bacteria could transform complex wastewater that contains recalcitrant organic compounds with a resultant recovery of useful products.
TL;DR: Low pH and presence of calcium may induce low stability that resist erosion in the MBRs, while on the other hand, these conditions may induce the formation of an elastic and viscous EPS layer fouling the ultrafiltration (UF) membrane.
Abstract: Extracellular polymeric substances (EPS) comprising the microbial biofilms in membrane bioreactor (MBR) systems are considered the most significant factor affecting sludge viscoelastic properties as well as membrane fouling. Understanding the water chemistry effects on EPS viscoelastic, conformational, and adherence properties are critical for defining the microbial biofilm’s propensity of fouling the membrane surface. In this study, EPS extracted from a hybrid growth membrane bioreactor (HG-MBR) were analyzed for their adherence, viscoelastic properties and size distribution using quartz crystal microbalance with dissipation monitoring (QCM-D) and dynamic light scattering (DLS), respectively. Also, adsorption characteristics of EPS extracted from different locations in the HG-MBR (bioreactor liquor, fluidized carriers, and membrane surface) were defined and linked to the extent of the total polysaccharide content in the EPS. In accordance with the Derjaguin−Landau−Verwey−Overbeek (DLVO) theory, more EPS ...
TL;DR: It is demonstrated that the SimCell™ platform operated under fed‐batch conditions could support viable cell concentrations up to at least 12 × 106 cells/mL and both intra‐MB (MB to MB) as well as intra‐MBA (MBA to MBA) culture performance was found to be highly reproducible.
Abstract: With increasing timeline pressures to get therapeutic and vaccine candidates into the clinic, resource intensive approaches such as the use of shake flasks and bench-top bioreactors may limit the design space for experimentation to yield highly productive processes. The need to conduct large numbers of experiments has resulted in the use of miniaturized high-throughput (HT) technology for process development. One such high-throughput system is the SimCell™ platform, a robotically driven, cell culture bioreactor system developed by BioProcessors Corp. This study describes the use of the SimCell™ micro-bioreactor technology for fed-batch cultivation of a GS-CHO transfectant expressing a model IgG4 monoclonal antibody. Cultivations were conducted in gas-permeable chambers based on a micro-fluidic design, with six micro-bioreactors (MBs) per micro-bioreactor array (MBA). Online, non-invasive measurement of total cell density, pH and dissolved oxygen (DO) was performed. One hundred fourteen parallel MBs (19 MBAs) were employed to examine process reproducibility and scalability at shake flask, 3- and 100-L bioreactor scales. The results of the study demonstrate that the SimCell™ platform operated under fed-batch conditions could support viable cell concentrations up to least 12 × 106 cells/mL. In addition, both intra-MB (MB to MB) as well as intra-MBA (MBA to MBA) culture performance was found to be highly reproducible. The intra-MB and -MBA variability was calculated for each measurement as the coefficient of variation defined as CV (%) = (standard deviation/mean) × 100. The % CV values for most intra-MB and intra-MBA measurements were generally under 10% and the intra-MBA values were slightly lower than those for intra-MB. Cell growth, process parameters, metabolic and protein titer profiles were also compared to those from shake flask, bench-top, and pilot scale bioreactor cultivations and found to be within ±20% of the historical averages. Biotechnol. Bioeng. 2010; 106: 57–67. © 2010 Wiley Periodicals, Inc.
TL;DR: Results show that the bioreactor chambers can increase or maintain cell viability and function when the flow rates are below 500 µL/min, corresponding to wall shear stresses of 10−5 Pa or less at the cell culture surface.
Abstract: A generic "system on a plate" modular multicompartmental bioreactor array which enables microwell protocols to be transferred directly to the bioreactor modules, without redesign of cell culture experiments or protocols is described. The modular bioreactors are simple to assemble and use and can be easily compared with standard controls since cell numbers and medium volumes are quite similar. Starting from fluid dynamic and mass transport considerations, a modular bioreactor chamber was first modeled and then fabricated using "milli-molding," a technique adapted from soft lithography. After confirming that the shear stress was extremely low in the system in the range of useful flow rates, the bioreactor chambers were tested using hepatocytes. The results show that the bioreactor chambers can increase or maintain cell viability and function when the flow rates are below 500 microL/min, corresponding to wall shear stresses of 10(-5) Pa or less at the cell culture surface.
TL;DR: The encapsulated systems consistently showed improved performance over the nonencapsulated cells, indicating that the protection conferred by the alginate matrix plays a relevant role in maintaining the hepatocyte functionalities in vitro.
Abstract: The maintenance of differentiated hepatocyte phenotype in vitro depends on several factors-in particular, on extracellular matrix interactions, for example, with three-dimensional (3D) matrices. Alginate hydrogel provides the cells with a good extracellular matrix due to the formation of a massive capsule with semi-permeable properties that allows for diffusion of the medium components into the cells as well as efficient waste product elimination. Simultaneously, alginate protects the cells from shear stress caused by the hydrodynamics when cultured in stirred systems such as bioreactors. We have previously developed a hepatocyte aggregate 3D culture system in a bioreactor where improved hepatocyte functionality could be maintained over longer periods (21 days). In this work, ultra-high-viscosity alginate was used for hepatocyte aggregates entrapment. Hepatocyte biotransformation (phase I and II enzymes), CYP450 inducibility, and secretory capacity (albumin and urea production) were monitored. The analyses were performed in both spinner vessels and bioreactors to test the effect of the pO(2) control, unavailable in the spinners. Performance of alginate-encapsulated hepatocyte aggregates in culture was compared with nonencapsulated aggregate cultures in both bioreactor (controlled environment) and spinner vessels. For both culture systems, hepatocytes' metabolic and biotransformation capacities were maintained for up to 1 month, and encapsulated cells in bioreactors showed the best performance. In particular, albumin production rate increased 2- and 1.5-fold in encapsulated aggregates compared with nonencapsulated aggregates in bioreactor and spinner vessels, respectively. Urea production rate increased twofold in encapsulated cultures compared with nonencapsulated cells, in both bioreactor and spinner vessels. Similarly, in both the bioreactor and the spinner system, cell encapsulation resulted in a 1.5- and 2.8-fold improvement of hepatocyte 7-ethoxycoumarin and uridine diphosphate glucuronosyltransferases (UGT) activities, respectively. For all parameters, but for UGT activity, the bioreactor system resulted better than the spinner vessels; for UGT activity no difference was observed between the two. Furthermore, both encapsulated and nonencapsulated 3D culture systems were inducible by 3-methylcholanthrene and dexamethasone. The encapsulated systems consistently showed improved performance over the nonencapsulated cells, indicating that the protection conferred by the alginate matrix plays a relevant role in maintaining the hepatocyte functionalities in vitro.
TL;DR: This study evaluated the potential biodegradability of the endogenous residue in activated sludge subjected to batch digestion under either non-aerated or alternating aerated and non- aerated conditions.
TL;DR: Anaerobic pre-treatment is not feasible and an aerobic system is preferred for the treatment of greywater, which resulted in a COD removal significantly higher than 51% removal by anaerobic treatment.
Abstract: Greywater consists of household wastewater excluding toilet discharges. Three systems were compared for the biological treatment of greywater at a similar hydraulic retention time of approximately 12–13 hours. These systems were aerobic treatment in a sequencing batch reactor, anaerobic treatment in an up-flow anaerobic blanket reactor and combined anaerobic-aerobic treatment (up-flow anaerobic blanket reactor + sequencing batch reactor). Aerobic conditions resulted in a COD removal of 90%, which was significantly higher than 51% removal by anaerobic treatment. The low removal in the anaerobic reactor may have been caused by high concentration of anionic surfactants in the influent (43.5 mg/L) and a poor removal of the colloidal fraction of the COD in up-flow anaerobic sludge blanket reactors. Combined aerobic-anaerobic treatment accomplished a COD removal of 89%, similar to the aerobic treatment alone. Greywater methanization was 32% for the anaerobic system and 25% for the anaerobic-aerobic system, yielding a small amount of energy. Therefore, anaerobic pre-treatment is not feasible and an aerobic system is preferred for the treatment of greywater.
TL;DR: Application of aerobic granule can improve sludge filtering properties and delay the process of membrane fouling, as a result of better morphological structure and lower EPS content.
TL;DR: The results indicate that compared to conventional wastewater treatment systems, longer solids retention times should be considered in phototrophic bioreactors for complete nitrification and nitrogen removal.
Abstract: Nitrifying bacteria, cyanobacteria, and algae are important microorganisms in open pond wastewater treatment systems. Nitrification involving the sequential oxidation of ammonia to nitrite and nitrate, mainly due to autotrophic nitrifying bacteria, is essential to biological nitrogen removal in wastewater and global nitrogen cycling. A continuous flow autotrophic bioreactor was initially designed for nitrifying bacterial growth only. In the presence of cyanobacteria and algae, we monitored both the microbial activity by measuring specific oxygen production rate (SOPR) for microalgae and cyanobacteria and specific oxygen uptake rate (SOUR) for nitrifying bacteria. The growth of cyanobacteria and algae inhibited the maximum nitrification rate by a factor of 4 although the ammonium nitrogen fed to the reactor was almost completely removed. Terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that the community structures of nitrifying bacteria remained unchanged, containing the dominant Nitrosospira, Nitrospira, and Nitrobacter species. PCR amplification coupled with cloning and sequencing analysis resulted in identifying Chlorella emersonii and an uncultured cyanobacterium as the dominant species in the autotrophic bioreactor. Notwithstanding their fast growth rate and their toxicity to nitrifiers, microalgae and cyanobacteria were more easily lost in effluent than nitrifying bacteria because of their poor settling characteristics. The microorganisms were able to grow together in the bioreactor with constant individual biomass fractions because of the uncoupled solids retention times for algae/cyanobacteria and nitrifiers. The results indicate that compared to conventional wastewater treatment systems, longer solids retention times (e.g., by a factor of 4) should be considered in phototrophic bioreactors for complete nitrification and nitrogen removal.
TL;DR: Anaerobic oxidation of methane coupled to sulphate reduction (SR-AOM) prevents oceanic methane emissions and is considered as a major environmental process in the deep-sea sediments and there was an inhibitory effect observed after 2 days, probably due to the accumulation of sulphide and the increase of pH.
TL;DR: It is demonstrated that this adsorption-photocatalysis hybrid technology can be used as a feasible alternative treatment process for wastewater reclamation.
TL;DR: The results suggest that the SAnMBR is a promising technology for energy recovery from kraft evaporator condensate and Bubbling of recycled biogas was effective for in‐situ membrane cleaning, depending on theBiogas sparging rate used.
Abstract: Submerged anaerobic membrane bioreactor (SAnMBR) technology was studied for kraft evaporator condensate treatment at 37 ± 1°C over a period of 9 months. Under tested organic loading rates of 1–24 kg COD/m3/day, a chemical oxygen demand (COD) removal efficiency of 93–99% was achieved with a methane production rate of 0.35 ± 0.05 L methane/g COD removed and a methane content of 80–90% in produced biogas. Bubbling of recycled biogas was effective for in‐situ membrane cleaning, depending on the biogas sparging rate used. The membrane critical flux increased and the membrane fouling rate decreased with an increase in the biogas sparging rate. The scanning electron microscopy images showed membrane pore clogging was not significant and sludge cake formation on the membrane surface was the dominant mechanism of membrane fouling. The results suggest that the SAnMBR is a promising technology for energy recovery from kraft evaporator condensate.
TL;DR: This paper examined the performance of five North American bioreactor landfills and found that gas collection increases at bioreactors when the water content reaches 40% of the leachates were commingled from cells operating as a bio-actor.
Abstract: The objective of this research was to examine the performance of five North American bioreactor landfills. This paper represents the second of a two-part series and addresses biological and chemical aspects of bioreactor performance including gas production and management, and leachate chemistry. The data support accelerated methane generation at several landfills ( k=0.08–0.21 1/year ) relative to the AP-42 default decay rate ( k=0.04 1/year ) . While the data indicate that gas collection increases at bioreactor landfills, a general relationship between decay rate and moisture added or wet weight water content could not be identified. There was no indication that gas collection increases appreciably when the water content reaches 40%. Most of the leachates at the landfills in this study were commingled from cells operating as a bioreactor and conventionally. Nevertheless, trends in pH and BOD:COD in the bioreactor leachates were consistent with the impacts of enhanced biological activity. Ammonia concent...