Bioremediation of petroleum hydrocarbon contaminated soil is studied using the slurry bioreactor. This method overcomes the limitations of the mass transfer rates and thereby improves the extent of degradation as compared to the... more
Bioremediation of petroleum hydrocarbon contaminated soil is studied using the slurry bioreactor. This method overcomes the limitations of the mass transfer rates and thereby improves the extent of degradation as compared to the conventional bioremediation techniques. Soil from crude oil producing well site was used for the study. Three different microorganisms were isolated and their bio-surfactant producing capacity was studied. The three best organisms were used for bioremediation using slurry bioreactor. The reduction in the Total Petroleum Hydrocarbon (TPH) for different microorganisms was studied over the period of 72 hours. The variation in other parameters such as Dissolved Oxygen (DO), pH and Colony Forming Units (CFU/ml) was studied. The criterion for selection of microorganism suitable for the bioremediation process using slurry reactor is proposed. The current work highlights the importance of the treatability studies in the bioremediation of contaminated soil for large scale applications of slurry reactor technology.
Manufacturing of cellular products for therapeutic purposes like stem cell or cancer therapy requires equipment with specific characteristics not always addressed by conventional technologies. A new integrated cell processing device is... more
Manufacturing of cellular products for therapeutic purposes like stem cell or cancer therapy requires equipment with specific characteristics not always addressed by conventional technologies. A new integrated cell processing device is presented that can handle all current technical requirements for manufacturing cellular products by automation of the complete process in a GMP-compliant single-use tubing set. Its capabilities are exemplified in the presented study by successful processing of adult stem cells, natural killer cells, and several cell lines. Multiple cell processing workflows can be automated in a functionally closed environment: from cell separation through cell culture to formulation of the final product.
Membrane bioreactor (MBR) is a reliable and promising technology for wastewater treatment and reclamation applications. In spite of more than a decade of significant advances in developing fouling mitigation methods, different physical... more
Membrane bioreactor (MBR) is a reliable and promising technology for wastewater treatment and reclamation applications. In spite of more than a decade of significant advances in developing fouling mitigation methods, different physical and cleaning protocols are still necessary to be developed to limit the membrane fouling. The use of scouring agents in MBR applications has been paid attention as a new approach as an energy-efficient way to control membrane fouling. Recently, mechanical cleaning by scouring agents is becoming as intense research area considering high efficiency of fouling reduction while requiring low energy consumption. In this review, fundamental and comprehensive assessments of the mechanical cleaning concepts and their applications with porous and nonporous scouring agents for MBR system are critically reviewed. The existing challenges and future research prospects on the mechanical cleaning technology associated with scouring agents for the MBR applications are also discussed.
The kinetics and biodegradation of both thiosulphate and methanol were studied under anaerobic condition using batch experiments, at ambient temperature and alkaline conditions. Mixed microbial consortia obtained from a previously... more
The kinetics and biodegradation of both thiosulphate and methanol were studied under anaerobic condition using batch experiments, at ambient temperature and alkaline conditions. Mixed microbial consortia obtained from a previously operated biotrickling filter (BTF) and fresh activated sludge was used as the biomass source. The growth of biomass during batch experiments correlated well with the accumulation of sulphate and sulphide. The production of sulphide and sulphate during the first few days of incubation was almost instantaneous due to the growth of biomass. The production of hydrogen sulphide declined after the sixth day of batch incubation due to the depletion of thiosulphate substrate. Thiosulphate degradation was fast (~8 days), leading to the formation of sulphide and sulphate species. Compared to the activity of BTF acclimated biomass, the biokinetic activity of activated sludge in the lag phase of the batch experiment was low. It required additional time to acclimatize itself to the new environment containing methanol and thiosulfate. The biomass growth rate (μ) observed in the batch experiment varied between 0.002 and 0.12 h-1. The degradation rate of thiosulphate in the batch reactor during 9 days of experiment time varied between 0.02 and 0.8 per day. However, the activities of the two biomass samples were different. A maximum thiosulphate degradation rate of 0.8 d-1 was achieved in batch experiments inoculated with biomass from the BTF reactor. A maximum biomass yield coefficient of 0.7 gbiomass gmethanol-1
A strategy for adaptive control and energetic optimization of aerobic fermentors was implemented, with both air flow and agitation speed as manipulated variables. This strategy is separable in its components: control, optimization,... more
A strategy for adaptive control and energetic optimization of aerobic fermentors was implemented, with both air flow and agitation speed as manipulated variables. This strategy is separable in its components: control, optimization, estimation. We optimized parameter’s estimation (from the usual KLa correlation) using sinusoidal excitation of air flow and agitation speed. We have implemented parameter’s estimation trough recursive least squares algorithm with forgetting factor. We carried separate essays on control, optimization and estimation algorithms. We carried our essays using an original computational simulation environment, with noise and delay generating facilities for data sampling and filtering.
Our results show the convergence and robustness of the estimation algorithm used, improved with use of both forgetting factor and KLa dead-band facilities. Control algorithm used in our work compares favorably with PID using the integrated area criteria for deviation between oxygen molarity and critical molarity (set point). Optimization algorithm clearly reduces energetic consumption, respecting critical molarity. Integration of control, optimization and adaptive algorithms was implemented, but future work is needed for stability. Methods were defined and implemented for stability improvement. We have implemented data acquisition and computer manipulation of air flow and agitation speed for actual fermentors.
The need for high biodegradation rates requires application of microorganisms in controlled environmental and nutritional conditions. Soil slurry bioremediation is a powerful alternative to conventional methods in resolving environmental... more
The need for high biodegradation rates requires application of microorganisms in controlled environmental and nutritional conditions. Soil slurry bioremediation is a powerful alternative to conventional methods in resolving environmental oil contamination problems. This work studied the technical viability of treating soil slurry biologically by stimulation of native microorganisms. Oil contaminated mangrove soil from Alakiri, Nigeria was mixed with water at 1:3 ratio and treated in three different ways (A, B and C). Statistical increase in microbial population and hydrocarbon removal efficiency were observed. In terms of total petroleum hydrocarbon degradation, removal efficiency of 55.31% was achieved in Slurry B (amended and stirred slurry), closely followed by 53.21% of Slurry A (unamended and stirred slurry) and 31.58% for slurry C (amended and unstirred slurry). The importance of mechanical mixing on the microbial population dynamics and on the biodegradation of the oil was ascertained. This study has shown that slurry bioreactor is effective in the bioremediation of soils containing oil-contaminants.
The current studies were aimed at to investigate role of pH, dissolved oxygen for production protease in bioreactor by alkalophilic bacterium and application of saw dust for its purification. The production of proteolytic enzyme by... more
The current studies were aimed at to investigate role of pH, dissolved oxygen for production protease in bioreactor by alkalophilic bacterium and application of saw dust for its purification. The production of proteolytic enzyme by Bacillus subtilis IC-5 started as pH of medium falls to 9 and reached to maximum at pH 7 i.e., 4400 Uml-1. Likewise dissolved oxygen decreased in the medium as the protease production progresses. Saw dust was successively utilized for partial purification of protease. The partial purification of protease increased the specific activity to5.3 fold. The optimum pH and temperature for purified activity was 11 and 70 0 C, respectively. The purified enzyme was stable up to pH 12 and 80 o C.
Shoot cultures of Bacopa monnieri L. (Brahmi) were cultivated in shake flask (1 L) and two bioreactor systems: Growtek® (1 L) and modified bench top air lift bioreactor (ALB) (5 L). Continuous immersion and aeration supported excellent... more
Shoot cultures of Bacopa monnieri L. (Brahmi) were cultivated in shake flask (1 L) and two bioreactor systems: Growtek® (1 L) and modified bench top air lift bioreactor (ALB) (5 L). Continuous immersion and aeration supported excellent growth and enhanced levels of bacoside (A 3 +A 2) production in ALB. Growth index (GI) in terms of dry wt was recorded maximum in the ALB (5.84), followed by Growtek® (4.22) and shake flasks (2.61) after 4 wk of incubation. ALB recorded the highest number of shoots (443.33), as compared to that in Growtek® (42.67) and shake flasks (23.33). Furthermore, bacoside production in shoot cultures of the ALB system was ~ 1.75-fold higher as compared to cultures in shake flask. Nutrient exhaustion in spent medium from the various systems was also measured. Present work reports the feasibility of shoot cultivation in liquid medium to develop a suitable bioreactor strategy.
The objective is to conclude the modelling study of different process modes for retroviral production in a fixed bed reactor (FBR), by means of a modelling and experimental study of the different process modes for retroviral production in... more
The objective is to conclude the modelling study of different process modes for retroviral production in a fixed bed reactor (FBR), by means of a modelling and experimental study of the different process modes for retroviral production in FBR, in order to obtain and adjusted a mathematical model suitable for this process.
Mesenchymal stem cells (MSCs) are considered as primary candidates for cell-based therapies due to their multiple effects in regenerative medicine. Pre-conditioning of MSCs under physiological conditions—such as hypoxia, three-dimensional... more
Mesenchymal stem cells (MSCs) are considered as primary candidates for cell-based therapies due to their multiple effects in regenerative medicine. Pre-conditioning of MSCs under physiological conditions—such as hypoxia, three-dimensional environments, and dynamic cultivation—prior to transplantation proved to optimize their therapeutic efficiency. When cultivated as three-dimensional aggregates or spheroids, MSCs display increased angiogenic, anti-inflammatory, and immunomodulatory effects as well as improved stemness and survival rates after transplantation, and cultivation under dynamic conditions can increase their viability, proliferation, and paracrine effects, alike. Only few studies reported to date, however, have utilized dynamic conditions for three-dimensional aggregate cultivation of MSCs. Still, the integration of dynamic bioreactor systems, such as spinner flasks or stirred tank reactors might pave the way for a robust, scalable bulk expansion of MSC aggregates or MSC-derived extracellular vesicles. This review summarizes recent insights into the therapeutic potential of MSC aggregate cultivation and focuses on dynamic generation and cultivation techniques of MSC aggregates.
The three dimensional (3D) cultivation of stem cells in dynamic bioreactor systems is essential in the context of regenerative medicine. Still, there is a lack of bioreactor systems that allow the cultivation of multiple independent... more
The three dimensional (3D) cultivation of stem cells in dynamic bioreactor systems is essential in the context of regenerative medicine. Still, there is a lack of bioreactor systems that allow the cultivation of multiple independent samples under different conditions while ensuring comprehensive control over the mechanical environment. Therefore, we developed a miniaturized, parallelizable perfusion bioreactor system with two different bioreactor chambers. Pressure sensors were also implemented to determine the permeability of biomaterials which allows us to approximate the shear stress conditions. To characterize the flow velocity and shear stress profile of a porous scaffold in both bioreactor chambers, a computational fluid dynamics analysis was performed. Furthermore, the mixing behavior was characterized by acquisition of the residence time distributions. Finally, the effects of the different flow and shear stress profiles of the bioreactor chambers on osteogenic differentiation of human mesenchymal stem cells were evaluated in a proof of concept study. In conclusion, the data from computational fluid dynamics and shear stress calculations were found to be predictable for relative comparison of the bioreactor geometries, but not for final determination of the optimal flow rate. However, we suggest that the system is beneficial for parallel dynamic cultivation of multiple samples for 3D cell culture processes.
During the last years an increasing number of in vitro models have been developed for drug screening and toxicity testing. Primary cultures of hepatocytes are, by far, the model of choice for those high-throughput studies but their... more
During the last years an increasing number of in vitro models have been developed for drug screening and toxicity testing. Primary cultures of hepatocytes are, by far, the model of choice for those high-throughput studies but their spontaneous dedifferentiation after some time in culture hinders long-term studies. Thus, novel cell culture systems allowing extended hepatocyte maintenance and more predictive long term in vitro studies are required.It has been shown that hepatocytes functionality can be improved and extended in time when cultured as 3D-cell aggregates in environmental controlled stirred bioreactors. In this work, aiming at further improving hepatocytes functionality in such 3D cellular structures, co-cultures with fibroblasts were performed. An inoculum concentration of 1.2 × 105 cell/mL and a 1:2 hepatocyte:mouse embryonic fibroblast ratio allowed to improve significantly the albumin secretion rate and both ECOD (phase I) and UGT (phase II) enzymatic activities in 3D co-cultures, as compared to the routinely used 2D hepatocyte monocultures. Significant improvements were also observed in relation to 3D monocultures of hepatocytes. Furthermore, hepatocytes were able to respond to the addition of beta-Naphtoflavone by increasing ECOD activity showing CYP1A inducibility. The dependence of CYP activity on oxygen concentration was also observed. In summary, the improved hepatocyte specific functions during long term incubation of 3D co-cultures of hepatocytes with fibroblasts indicate that this system is a promising in vitro model for long term toxicological studies.
Shoot cultures of Bacopa monnieri L. (Brahmi) were cultivated in shake flask (1 L) and two bioreactor systems: Growtek® (1 L) and modified bench top air lift bioreactor (ALB) (5 L). Continuous immersion and aeration supported excellent... more
Shoot cultures of Bacopa monnieri L. (Brahmi) were cultivated in shake flask (1 L) and two bioreactor systems: Growtek® (1 L) and modified bench top air lift bioreactor (ALB) (5 L). Continuous immersion and aeration supported excellent growth and enhanced levels of bacoside (A3+A2) production in ALB. Growth index (GI) in terms of dry wt was recorded maximum in the ALB (5.84), followed by Growtek® (4.22) and shake flasks (2.61) after 4 wk of incubation. ALB recorded the highest number of shoots (443.33), as compared to that in Growtek® (42.67) and shake flasks (23.33). Furthermore, bacoside production in shoot cultures of the ALB system was ~ 1.75-fold higher as compared to cultures in shake flask. Nutrient exhaustion in spent medium from the various systems was also measured. Present work reports the feasibility of shoot cultivation in liquid medium to develop a suitable bioreactor strategy.
This research was aimed at designing an industrial process for the production of Ogi from the fermentation of maize, using a powdered substrate. This was achieved by reviewing the traditional process and introducing a revised process. The... more
This research was aimed at designing an industrial process for the production of Ogi from the fermentation of maize, using a powdered substrate. This was achieved by reviewing the traditional process and introducing a revised process. The steps involved in the revised process included grinding, sieving, fermenting (under anaerobic conditions) and drying. Analysis of varying fermented samples to overall composition of substrate (2-10%), varying moisture content (83-152%), varying temperature (30-50℃) and time (4-84 hours); and their effect on the growth rate of the active microorganisms was carried out. Also, microbiology tests are carried out using the traditional process and the revised process and the observations recorded. A controlled environment is proven to be created by introducing anaerobic conditions to the process. The model is obtained from this analysis and the optimal values for the target acidity value of 2.9 is given. It is concluded from the results obtained that the revised process adopted in this research is suitable for industrial production of Ogi.
The aim of this study was to demonstrate that differences in the local composition of bi-zonal fibrocartilaginous tissues result in different local biomechanical properties in compression and tension. Bovine articular chondrocytes were... more
The aim of this study was to demonstrate that differences in the local composition of bi-zonal fibrocartilaginous tissues result in different local biomechanical properties in compression and tension. Bovine articular chondrocytes were loaded into hyaluronan-based meshes (HYAFF®-11) and cultured for 4 weeks in mixed flask, a rotary Cell Culture System (RCCS), or statically. Resulting tissues were assessed histologically, immunohistochemically, by scanning electron microscopy and mechanically in different regions. Local mechanical analyses in compression and tension were performed by indentation-type scanning force microscopy and by tensile tests on punched out concentric rings, respectively. Tissues cultured in mixed flask or RCCS displayed an outer region positively stained for versican and type I collagen, and an inner region positively stained for glycosaminoglycans and types I and II collagen. The outer fibrocartilaginous capsule included bundles (up to 2 μm diameter) of collagen fibers and was stiffer in tension (up to 3.6-fold higher elastic modulus), whereas the inner region was stiffer in compression (up to 3.8-fold higher elastic modulus). Instead, molecule distribution and mechanical properties were similar in the outer and inner regions of statically grown tissues. In conclusion, exposure of articular chondrocyte-based constructs to hydrodynamic flow generated tissues with locally different composition and mechanical properties, resembling some aspects of the complex structure and function of the outer and inner zones of native meniscus.
