Triglycerides are the majority lipid component of most biochemical mixtures and are virtually water insoluble. Lipid removal is desired prior to protein purification processing to decrease nonspecific fouling of downstream chromatographic matrices. Transgenic pig milk was used as a model system to study delipidation from therapeutic protein sources. The majority of triglycerides was extracted from stable lipid micelles and removed with a method that can be incorporated in downstream protein purification processing without denaturing the target protein. An efficient delipidation treatment used TNBP, a non-polar solvent, to extract lipid micelles and then phase transfer milk lipids into a TNBP-swelled dextran particulate. A batch incubation of a whey/TNBP mixture with pre-swollen Sephadex LH-20 or hydroxyalkoxypropyl dextran (HAPD) beads at 4 C for 24 hours removed 67 + 2 % (0.645 mg triglycerides/ml Sephadex LH-20) and 71 o + 1 % (0.628 mg triglycerides/ml HAPD) of the triglycerides present in the skimmed transgenic whey, respectively. Fully swollen beads removed 20% more triglycerides than beads which were wetted but not swollen in TNBP, indicating that a larger phase volume and internal adsorption of the lipids onto the Sephadex matrix dominates over surface adsorption. Polyclonal ELISAs indicated that 89 + 6% of the recombinant human Protein C was still present in the transgenic whey after this delipidation treatment, indicating this treatment did not denature or harm the target protein. / Master of Science

Yes / This study used sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis and a jar test apparatus to investigate the molecular weight (MW) and turbidity removal potential of Hibiscus seeds. Three Hibiscus species were assessed: okra crude extract (OCE), sabdariffa crude extract (SCE), and kenaf crude extract (KCE). Furthermore, purified versions of each [i.e., purified okra protein (POP), purified sabdariffa protein (PSP), and purified kenaf protein (PKP)] obtained from anionic exchange were evaluated. The results show that whereas the crude extracts had multiple proteins with MW sizes between 11 and 82 kDa, the purified samples consisted of a single coagulant protein band around 39 kDa. In each case, significant turbidity removal was recorded with the purified proteins; POP, PSP and PKP achieved approximately 98%, 94%, and 90% removal, respectively, at a reduced dosage of ≤0.6  mg/L. However, OCE and SCE achieved lower turbidity removal of 86% and 85% using 40-mg/L doses, respectively, whereas KCE recorded only 73% turbidity removal with a 60-mg/L dose. Sludge generation by crude and purified proteins was approximately 25% of sludge produced by aluminum sulfate and had the additional benefit of being biodegradable. Therefore, the coagulant protein in Hibiscus plant seeds has potential applications for improvements to accessing clean water in developing countries.

Yes / All neophyte contact lens wearers require training on how to handle contact lenses. Currently, almost no published information exists describing the most common approaches used by those involved in such training in soft contact lens wearers. This study aimed to gather information on the approaches taken by those conducting this training worldwide. An online survey was created in English and translated to Spanish and distributed internationally via social media, conference attendees, and professional contacts. The anonymous survey included information on workplace setting of respondents, information about the typical approaches used for application and removal of soft contact lenses, length of the appointment, and success rate with their approach. Survey responses were received between May 2021 and April 2022. A total of 511 individuals completed the survey and responses were received from 31 countries with 48.7% from the UK. The most common approach taught for application was to have the patient hold the upper eyelashes (84.7%) and to hold the lower eyelid with the same hand as the lens (89.4%). Lenses were applied directly to the cornea by 57.7% of the respondents. The most common approach taught for lens removal was to drag the lens inferiorly from the cornea prior to removal (49.3%). Most respondents did not use videos to aid the teaching appointment (62.0%); however, they felt that their approach was successful in most cases (90). Application and removal training sessions lasted a median of 30 min and contact lenses were typically dispensed after the instructor witnessing successful application and removal three times. Various methods are adopted globally for training of application and removal of soft contact lenses, with many advising a patient-specific approach is required for success. The results of this survey provide novel insights into soft contact lens handling training in clinical practice. / British & Irish University and College Contact Lens Educators (BUCCLE) receives sponsorship from CooperVision, Alcon, Bausch + Lomb and Johnson and Johnson. No specific grant was received for this study, and no sponsors had any input or involvement within this project. Nery Garcia-Porta is supported financially by a Maria Zambrano contract at USC under the grants call for the requalification of the Spanish university system 2021–2023, funded by the European Union—Next Generation EU.

The effects of temperature and mean cell residence time (MCRT) on processes involved in biological nitrogen and phosphorus removal were investigated by operating pilot-scale continuous-flow reactors over a range of temperatures and MCRITs. Two systems were operated as high-rate University of Cape Town (UCT) biological nutrient removal (BNR) processes. A third system was operated as a conventional, fully aerobic activated sludge system for comparison. Less aerobic volume was needed to achieve complete nitrification in the BNR system than in the conventional system when temperature and MCRT conditions were suitable for complete nitrification. This occurred at 15 d MCRT and temperatures from 10 to 20 °C., and at 5 d MCRT and 20 °C. However, the BNR system was more susceptible to nitrifier washout at 5 d MCRT and temperatures of 10 and 15 °C. Although less volume was needed for complete nitrification in the BNR system, specific nitrification rates and the degree of nitrification were equal in the two systems when compared on the basis of aerobic MCRT. This phenomenon occurred because the MLVSS concentrations were higher in the aerobic zone of the BNR system than in the conventional system for the same organic loading and total MCRT. Nitrification and denitrification rates were a function of MCRT and temperature, with temperature having a greater effect at lower MCRTs. Batch experiments showed that anoxic uptake of phosphorus occurred, although at a much lower rate than aerobic uptake. Biological phosphorus removal was adversely affected by colder temperatures. Operation of the BNR process at the lowest MCRT which provided complete nitrification prevented washout of phosphorus removal organisms, and provided the best combined nitrogen and phosphorus removal when phosphorus removal was COD-limited. Higher MCRIs were optimal under P-limiting conditions. Anaerobic stabilization ranging from 8% to 27% was measured in the BNR system, and was a function of temperature at a 15 d MCRI. A mechanism for anaerobic stabilization was proposed. Yield coefficients for the BNR and the conventional system were equal and were 0.41 mgVSS/mgCOD. The decay rate in the BNR system, 0.063 d⁻¹, was lower than the decay rate in the conventional system, 0.110 d⁻¹. This resulted in higher MLVSS concentrations in the BNR system. / Ph. D.

The role of metal cations in enhanced biological phosphorus removal (EBPR) from wastewater by activated sludge was investigated. Potassium and magnesium were simultaneously required for efficient EBPR. Neither potassium nor magnesium could induce enhanced phosphorus uptake on its own. Cations were co-transported with phosphorus during anaerobic release and aerobic uptake. With every mole of phosphorus, between 0.23 and 0.43 moles of potassium and between 0.25 and 0.36 moles of magnesium were co-transported. Calcium appeared to be involved in EBPR to a limited extent, and did not seem to chemically co-precipitate with phosphorus. For every gram of chemical oxygen demand (COD) consumed by the sludge in the anaerobic zone of the experimental systems, 0.22 grams of phosphorus were released at a 15 d mean cell residence time and 20°C. Approximately 20 mgCOD/L were taken up by the sludge before any phosphorus was released. Phosphorus release could be described by first order kinetics. Phosphorus uptake under aerobic conditions could also be described by first order kinetics. The total phosphorus uptake in the anoxic and aerobic zones of the experimental systems was proportional to the total phosphorus release in the anaerobic zone. For every gram of phosphorus released, between 1.1 and 1.2 grams of phosphorus were taken up by the sludge regardless of the operating conditions. Phosphorus uptake by the sludge in the aerobic phase was hindered by the presence of acetate in solution. Uptake commenced only after all of the available acetate was first consumed by the sludge. Distilled water, 0.85 percent sodium chloride, and 5 mM and 50 mM ethylene diamine tetra-acetic acid were used to extract chemically precipitated phosphorus from EBPR sludge. Each of the washing media seemed to cause some cell lysis, suggested by the extraction of non-reactive phosphorus. The duration of wash seemed to affect the extent of cell lysis. Phosphorus fractionation extracts were assayed for deoxyribonucleic acid to determine whether cell lysis occurred. The assay was apparently not affected by the contents of the sludge supernatant. / Ph. D.

This thesis explores landscape's framing role in memorialization through a discussion of southeastern United States mill villages. This paper moves the preservation discussion from the architectural realm of an isolated textile mill building to the scale of the landscape encompassing the entire infrastructure of mill life. The beginning of the 20th century witnessed the transformation of the piedmont region of South Carolina from a farmland of sharecroppers to the cotton textile center of the nation. This rapid industrialization altered rolling landscape and winding creeks into a series of mill villages and dammed waterways connecting larger cities of neighborhood mills. The beginning of the 21st century is witnessing another transformation, the shuttering of those mills because of globalization and a trend toward adaptive reuse into luxury apartments. While this form of preservation rescues a portion of the deteriorating memory infrastructure, it threatens to distort or erase the unique relationship between mill and mill village by romanticizing mill life and brushing over the complex history of labor present in those spaces. The landscape reveals that the mills channeled not only human labor, but also the work force of nature through dams regulating waterways. Like the social restructuring of the mills, this restructuring of nature had impacts: disturbed ecologies, toxic sedimentation, and altered waterways. Investigation proceeds through a research and design process. Research includes creating a spatial data set of the mills in the South Carolina piedmont region from a list in the 1930 edition of Clark's directory of southern textile mills. This mapping along with watershed analysis determines a specific mill site for intervention along a waterway where dams have impaired the natural ecology. The design explores the potential of revising or removing the mill dam, a piece of memory infrastructure, and wrestles with the balance of preservation and ecological restoration. / Master of Landscape Architecture / Many old textile mills in the southeastern United States have been adapted into high-end condos. This project questions that practice. Because of this practice the difficult labor history of the mills is slowly being erased, and there is a separation between the high-end housing of the mill and the low-end mill village housing. This project looks at the broader area around the mills and creates a landscape that tells some of the mill history, while providing affordable housing. The project explores how the same decision making that made working life difficult in the mills also polluted the environment. Changing the former dam and constructing a new one creates a public park and an amenity to the new affordable housing. The solution helps remember the cultural and natural history of the mill past and creates a space for people while improving the environment.

L'estimation des abondances de population est essentielle pour comprendre les dynamiques de population, les interactions entre espèces et estimer les risques de transmission d'agents pathogènes dans les populations. Plusieurs méthodes d'échantillonnages, basées sur des hypothèses spécifiques permettent d'estimer ces abondances : les méthodes par comptages uniques, par « distance sampling », par échantillonnages successifs ou par capture marquage recapture. Nous nous sommes intéressés à l'abondance des tiques Ixodes ricinus, vecteurs de nombreux agents pathogènes. Cette abondance est classiquement estimée par le nombre de tiques capturées lors d'échantillonnages uniques réalisés sur différentes unités d'observation. Cependant, de nombreuses études remettent en cause cette hypothèse forte et suggèrent que le taux d'échantillonnage est variable selon les conditions d'échantillonnage (type de végétation,…) mais ne prennent pas en compte ce taux d'échantillonnage pour autant. A partir d'une méthode d'échantillonnage par « removal sampling » (RS), (i) nous avons montré que les conditions environnementales influençaient le taux d'échantillonnage et l'indicateur d'abondance usuel i.e. le nombre de tiques capturées lors d'un seul échantillonnage (ii) nous avons proposé une méthode pour détecter l'indicateur d'abondance, basés sur le nombre cumulé de capture, le moins soumis aux variations du taux ; (iii) par une approche Bayésienne hiérarchique, nous avons estimé simultanément l'abondance de tiques des unités d'observation et la valeur du taux d'échantillonnage en fonction du type de végétation et de l'heure d'échantillonnage. Nous avons montré que le taux d'échantillonnage sur des arbustes (entre 33,9 % et 47,4%) était significativement inférieur au taux d'échantillonnage sur des feuilles mortes (entre 53,6 % et 66,7%). De plus, nous avons montré que le modèle RS tend vers un modèle de Poisson iid lorsque la taille de la population N0 tend vers l'infini ce qui pose des problèmes d'indétermination pour estimer les paramètres N0 et τ, le taux d'échantillonnage. Nous avons également montré que (i) les estimateurs Bayésiens divergent lorsque les lois a priori sont des lois vagues ; (ii) les lois a priori β(a, b) avec a > 2 sur τ conduisaient à des estimateurs Bayésien convergents. Enfin, nous avons proposé des recommandations quant au choix des lois a priori pour τ afin d'obtenir de bonnes estimations pour N0 ou pour τ. Nous discutons de la pertinence des méthodes RS pour les tiques et des perspectives envisageables pour (i) estimer le risque acarologique représenté par la population de tiques potentiellement actives sur une unité d'observation, (ii) estimer un risque à l'échelle d'une parcelle, à savoir comment répartir l'effort d'échantillonnage entre le nombre d'unités d'observation et le nombre d'échantillonnages successifs par unités d'observation. / The estimation of animal abundance is essential to understand population dynamics, species interactions and disease patterns in populations and to estimate the risk of pathogens transmission. Several sampling methods such as single counts, distance sampling, removal sampling or capture mark recapture could be used to estimate abundance. In this study, we are investigated the abundance of Ixodes ricinus ticks, which are involved in the transmission of many pathogens. Tick abundance is commonly estimated by the number of nymphs captured during a single observation (a cloth dragged on a given surface). In this case, analyses of abundance patterns assumes that the probability of detecting a tick, hence the sampling rate, remains constant across the observations. In practice, however, this assumption is often not satisfied as the sampling rate may fluctuate between observation plots. The variation of sampling rate is never taken into account in estimations of tick abundance. Using a removal sampling design (RS), (i) we showed that the sampling rate and the usual abundance indicator (based on a single drag observation per spot) were both influenced by environmental conditions ; (ii) we proposed a method to determine the abundance indicator the least influenced by sampling rate variations ; (iii) using a hierarchical Bayesian model, we estimated simultaneously the abundance and the sampling rate according the type of vegetation, and the time of sampling. The sampling rate varied between 33,9 % and 47,4 % for shrubs and 53,6 % and 66,7 % for dead leaves. In addition, we show that the RS model tends to Poisson iid model when the population size N0 tends to infinite. This result conduct to infinite estimations for N0. We show that (i) Bayesian estimators were divergent for vague prior ; (ii) β(a, b) prior for a > 2 on τ conduct to convergent estimators. Then, we proposed recommendations for prior choice for τ parameter to give good estimations of N0 or τ. We discuss the relevance of RS for ticks and the possible perspectives to (i) estimate the acarologic risk associated to all potential active ticks for given spot, (ii) estimate the risk at the larger scale, i.e. how to distribute the sampling effort between number of spot and number of consecutive sampling by spot.

The treatment of deep carious lesions (DCLs) represents a challenge for dentists, as these lesions require removal of dentin in proximity to the pulp that represents a higher risk of ending in pulp exposure. There is increasing evidence supporting minimally invasive caries removal methods, such as stepwise excavation procedure (SWP), instead of non-selective (complete) dentin caries removal for the treatment of DCLs. However, recent research has indicated that dentists have not completely adopted less invasive caries removal methods for the management of DCLs. These studies have been primarily conducted in Europe or South America; thus, few studies have been conducted in the United States to understand dentists’ management options of deep carious lesions in permanent teeth. Additionally, the proportion of dentists who would be willing to adopt less invasive carious tissue removal is unknown, especially in the United States. This dissertation consists of three studies that analyzed the effectiveness of SWP, the factors associated with success, an assessment of its costs and the acceptability of this treatment among U.S dentists. Study I assessed the patient factors predicting a successful SWP by retrospectively investigating a sample from the University of Iowa College of Dentistry from January 2004 through December 2012. Study I showed that SWPs showed a 75% success rate when evaluated within 36 months of the initial treatment. Patients who had a successful SWP treatment were slightly younger than patients whose SWP treatment was not successful. Study II performed a cost-effectiveness analysis by comparing SWP vs. the standard caries treatment (complete caries removal). Study II showed that SWP significantly reduced cost, resulting in an average savings of 64% compared to TCR over a 5-year period. Study III consisted of a statewide survey that contacted 1,434 Iowa dentists with the aim of identifying the most important factors that influence dentists’ decisions for DCLs treatment using conjoint analysis. From the total, 36.4% (n=522) clinicians answered the survey. One of the main study findings was that among the three factors (hardness of dentin, depth of the lesion and patient age) depth of the lesion was the most important factor influencing dentists’s decision when selecting a less invasive caries removal method. Study III did not find any significant association between years of practicing dentistry, type of practice and practice setting regarding being willing to select a less invasive caries removal method. In conclusion, this dissertation has demonstrated that the stepwise caries removal is a cost-saving and highly successful treatment for the management of deep caries lesions. Studies I and II have shown that this method has a high clinical success rate and less long-term treatment costs. Regarding the acceptability of SWP among clinicians, this dissertation has shown that most dentists in Iowa would consider less invasive caries methods for a DCL; however, these techniques have not been completely adopted and accepted among American dentists. Thus, dentists should be trained in less invasive caries methods, given instruction about which criteria they should use to assess a DCL, and provide them with the best evidence-based strategies for managing deep lesions. The findings of this dissertation should engage stakeholders to provide dentists with professional incentives for using these techniques. Specifically, our results support the idea that SWP minimizes costs while providing the appropriate patient care.

<p>The mass transfer of ethanol and toluene from air stream to liquid phase, and bioremediation of contaminated air streams containing either ethanol or toluene have been investigated using a stirred tank bioreactor. This investigation was conducted in six phases: </p> 1) mass transfer experiments involving the transport of toluene and ethanol from contaminated air streams into the liquid phase,</p> 2) study of air stripping effects of ethanol and toluene out of the liquid phase,</p> 3) batch growth experiments to determine growth kinetic models and model parameters,</p> 4) bioremediation of ethanol or toluene as the sole substrate to determine the capacity of Pseudomonas putida (P. putida) (ATCC 23973) growth on these substrates,</p> 5) toluene removal from contaminated air streams using ethanol and benzyl alcohol as co-substrates, and</p> 6) modelling the above studies using metabolic pathways to better understand the bioremediation process.</p> <p>Preliminary oxygen mass transfer studies showed that the presence of ethanol in the liquid phase enhances the overall oxygen mass transfer coefficients. Increasing the ethanol concentration from 0 to 8 g/L caused the oxygen mass transfer coefficients to increase from 0.015 to 0.049 s-1, and from 0.017 to 0.076 s-1, for impeller speeds of 450 and 600 rpm, respectively. Mass transfer studies using ethanol vapor in the air stream demonstrated complete absorption into the aqueous phase of the bioreactor at all operating conditions investigated (air flowrates up to 2.0 L/min and inlet concentrations up to 95.0 mg/L) and therefore mass transfer coefficients for ethanol absorption could not be determined. On the other hand, toluene mass transfer coefficients could be measured and were found to be 8.3x10-4, 8.8x10-4 and 1.0x10-3 s-1 at agitation speeds of 300, 450 and 600 rpm, respectively. The ethanol air stripping parameters (b values) were determined (at initial ethanol liquid concentration of 8.6 g/L) to be 0.002 and 0.007 h-1 for air flow rates of 0.4 L/min (0.3 vvm) and 1.4 L/min (1 vvm), respectively. The toluene air stripping rates, at initial liquid toluene concentration of 440 mg/L, were found to be 1.9, 5.3, 10.4, and 12.6 h-1 for air flow rates of 0.4, 0.9, 1.4, 2.1 L/min, respectively, which is much higher than those of ethanol at the same air flow rates and stirring speed of 450 rpm. It was also observed that benzyl alcohol was not stripped to any detectable level at any of the operating conditions used in this study.</p> <p>The growth of <i>P. putida</i> using toluene as sole substrate was carried out at several operating conditions by varying the dilution rates (D) from 0.01 to 0.1 h-1, the toluene air inlet concentration from 4.5 to 23.0 mg/L and air flow rates of 0.25 to 0.37 L/min (resulting in inlet toluene loadings from 70 to 386 mg/L-h). Steady state operation could not be achieved with toluene as the sole substrate. Ethanol and benzyl alcohol were therefore used as co-substrates for the toluene removal process. In order to understand the kinetics of P. putida growing on ethanol or benzyl alcohol, batch growth experiments were carried out at different initial substrate concentrations. The specific growth rates determined from the batch runs showed that ethanol had no inhibition effect on the growth of P. putida. The growth on ethanol followed the Monod equation with the maximum growth rate of 0.56 h-1 and yield of 0.59. The results from the batch growth experiments on benzyl alcohol showed that benzyl alcohol inhibits the growth of P. putida when the initial concentration of benzyl alcohol in the growth media is increased. The maximum growth rate was 0.42 h-1 in the inhibition model and the yield value was 0.45. </p><p>By operating the bioreactor in continuous mode using a pure strain of <i>P. putida</i>, it was possible to continuously convert ethanol into biomass without any losses to the gas phase or accumulation in the bioreactor at inlet ethanol concentrations of 15.9 and 19.5 mg/L. With ethanol as a co-substrate, toluene was efficiently captured in the bioreactor and readily degraded by the same strain of P. putida. A toluene removal efficiency of 89% was achieved with an ethanol inlet concentration of 15.9 mg/L and a toluene inlet concentration of 4.5 mg/L. With the introduction of benzyl alcohol as co-substrate at a feed rate of 0.12 g/h, the toluene removal efficiency reached 97% at toluene inlet concentrations up to 5.7 mg/L. All the experimental results at steady state were obtained when the bioreactor operated in a continuous mode at a dilution rate of 0.1 h-1, an air flowrate of 0.4 L/min, an agitation speed of 450 rpm and a reactor temperature of 25.0oC. The results of this study indicate that the well-mixed bioreactor is a suitable technology for the removal of VOCs with both high and low water solubility from polluted air streams. The results were achieved at higher inlet pollutant concentrations compared to existing biofilter treatments.</p><p>A metabolic model has been developed to simulate the bioremediation of ethanol, benzyl alcohol and toluene. For continuous steady state operations, ethanol as a sole substrate required less maintenance for biomass growth (0.010 C-mol/C-mol-h) than bioremediations in the presence of toluene, as seen with the ethanol/toluene mixture (0.027 C-mol/C-mol-h), and the benzyl alcohol/toluene mixture (0.069 C-mol/C-mol-h).</p>

<p>The mass transfer of ethanol and toluene from air stream to liquid phase, and bioremediation of contaminated air streams containing either ethanol or toluene have been investigated using a stirred tank bioreactor. This investigation was conducted in six phases: </p> 1) mass transfer experiments involving the transport of toluene and ethanol from contaminated air streams into the liquid phase,</p> 2) study of air stripping effects of ethanol and toluene out of the liquid phase,</p> 3) batch growth experiments to determine growth kinetic models and model parameters,</p> 4) bioremediation of ethanol or toluene as the sole substrate to determine the capacity of Pseudomonas putida (P. putida) (ATCC 23973) growth on these substrates,</p> 5) toluene removal from contaminated air streams using ethanol and benzyl alcohol as co-substrates, and</p> 6) modelling the above studies using metabolic pathways to better understand the bioremediation process.</p> <p>Preliminary oxygen mass transfer studies showed that the presence of ethanol in the liquid phase enhances the overall oxygen mass transfer coefficients. Increasing the ethanol concentration from 0 to 8 g/L caused the oxygen mass transfer coefficients to increase from 0.015 to 0.049 s-1, and from 0.017 to 0.076 s-1, for impeller speeds of 450 and 600 rpm, respectively. Mass transfer studies using ethanol vapor in the air stream demonstrated complete absorption into the aqueous phase of the bioreactor at all operating conditions investigated (air flowrates up to 2.0 L/min and inlet concentrations up to 95.0 mg/L) and therefore mass transfer coefficients for ethanol absorption could not be determined. On the other hand, toluene mass transfer coefficients could be measured and were found to be 8.3x10-4, 8.8x10-4 and 1.0x10-3 s-1 at agitation speeds of 300, 450 and 600 rpm, respectively. The ethanol air stripping parameters (b values) were determined (at initial ethanol liquid concentration of 8.6 g/L) to be 0.002 and 0.007 h-1 for air flow rates of 0.4 L/min (0.3 vvm) and 1.4 L/min (1 vvm), respectively. The toluene air stripping rates, at initial liquid toluene concentration of 440 mg/L, were found to be 1.9, 5.3, 10.4, and 12.6 h-1 for air flow rates of 0.4, 0.9, 1.4, 2.1 L/min, respectively, which is much higher than those of ethanol at the same air flow rates and stirring speed of 450 rpm. It was also observed that benzyl alcohol was not stripped to any detectable level at any of the operating conditions used in this study.</p> <p>The growth of <i>P. putida</i> using toluene as sole substrate was carried out at several operating conditions by varying the dilution rates (D) from 0.01 to 0.1 h-1, the toluene air inlet concentration from 4.5 to 23.0 mg/L and air flow rates of 0.25 to 0.37 L/min (resulting in inlet toluene loadings from 70 to 386 mg/L-h). Steady state operation could not be achieved with toluene as the sole substrate. Ethanol and benzyl alcohol were therefore used as co-substrates for the toluene removal process. In order to understand the kinetics of P. putida growing on ethanol or benzyl alcohol, batch growth experiments were carried out at different initial substrate concentrations. The specific growth rates determined from the batch runs showed that ethanol had no inhibition effect on the growth of P. putida. The growth on ethanol followed the Monod equation with the maximum growth rate of 0.56 h-1 and yield of 0.59. The results from the batch growth experiments on benzyl alcohol showed that benzyl alcohol inhibits the growth of P. putida when the initial concentration of benzyl alcohol in the growth media is increased. The maximum growth rate was 0.42 h-1 in the inhibition model and the yield value was 0.45. </p><p>By operating the bioreactor in continuous mode using a pure strain of <i>P. putida</i>, it was possible to continuously convert ethanol into biomass without any losses to the gas phase or accumulation in the bioreactor at inlet ethanol concentrations of 15.9 and 19.5 mg/L. With ethanol as a co-substrate, toluene was efficiently captured in the bioreactor and readily degraded by the same strain of P. putida. A toluene removal efficiency of 89% was achieved with an ethanol inlet concentration of 15.9 mg/L and a toluene inlet concentration of 4.5 mg/L. With the introduction of benzyl alcohol as co-substrate at a feed rate of 0.12 g/h, the toluene removal efficiency reached 97% at toluene inlet concentrations up to 5.7 mg/L. All the experimental results at steady state were obtained when the bioreactor operated in a continuous mode at a dilution rate of 0.1 h-1, an air flowrate of 0.4 L/min, an agitation speed of 450 rpm and a reactor temperature of 25.0oC. The results of this study indicate that the well-mixed bioreactor is a suitable technology for the removal of VOCs with both high and low water solubility from polluted air streams. The results were achieved at higher inlet pollutant concentrations compared to existing biofilter treatments.</p><p>A metabolic model has been developed to simulate the bioremediation of ethanol, benzyl alcohol and toluene. For continuous steady state operations, ethanol as a sole substrate required less maintenance for biomass growth (0.010 C-mol/C-mol-h) than bioremediations in the presence of toluene, as seen with the ethanol/toluene mixture (0.027 C-mol/C-mol-h), and the benzyl alcohol/toluene mixture (0.069 C-mol/C-mol-h).</p>