An improved steady-state method combining experiment and mathematical modelling has been developed to characterize the scalable convective heat transfer coefficient, hvol [W*m^(-3)*K^(-1)], of uncoated and catalyst-support coated aluminium foam monoliths. The values of hvol were recovered by parameter fitting its model values to experimental temperature data for steady-state air-cooled monoliths under a known heating flux. The model was built with experimentally recovered values of the monolith’s thermal conductivity and fluid permeability along with known values for other physical parameters. The volumetric heat transfer coefficients of 10, 20 and 40 pore-per-inch uncoated aluminium foams were determined to range between 2,700 and 20,000 W*m^(-3)*K^(-1) at channel Reynolds numbers between 85 and 1,700. The presence of a 76 micron thick anodized layer of catalyst support on monolith foams effected a small but significant reduction in the value of hvol. Coating with an anodized layer also reduced the permeabilities of the monoliths to air flow by 4-20%. Knowledge of the scalable parameter, hvol, was used to model a steady-state non-isothermal, non-isobaric heat-coupled methanol reformer. The model shows that changes to the convective transfer coefficient due to coating the monolith with catalyst support may have significant consequences for the thermal profile of the model reactor and for the product yield. / Thesis (Master, Chemical Engineering) -- Queen's University, 2011-12-12 20:11:18.046

A ciclodextrina glicosiltransferase (CGTase) é a única enzima capaz de catalisar a reação de ciclização a partir do amido e, assim, formar oligossacarídeos cíclicos conhecidos como ciclodextrinas (CDs). Através desta reação é produzida uma mistura de α-, β- e γ-CD que, respectivamente, contém 6, 7 e 8 resíduos de glicose. As CDs têm atraído enorme atenção devido ao seu grande potencial de aplicação em diversas áreas da indústria. Potencial este proporcionado por sua estrutura cônica, com interior hidrofóbico, capaz de encapsular sólidos, líquidos e gases, conferindo propriedades importantes e protegendo-os. Neste trabalho foi estudada a imobilização de uma CGTase em sílica mesoporosa de forma direcionada às cisteínas presentes em sua superfície, alterando a exposição do sítio ativo. A ligação via cisteínas nativas da proteína aumentou em quatro vezes a eficiência da imobilização, quando comparada a ligação via grupamento amino. Esta, no entanto, apresentou maior atividade enzimática em faixas mais amplas de temperatura e pH, além de maior estabilidade operacional, mantendo 100 % de sua atividade após 200 h de reação contínua a 60 °C e pH 4. Ainda que apresentando menor estabilidade da ligação, o derivado obtido por ligação dissulfeto manteve 40 % da atividade inicial durante 200 h e então, o suporte pôde ser recarregado e reutilizado por igual período. Os suportes desenvolvidos apresentaram estabilidade satisfatória, possibilitando o uso do derivado imobilizado em reator de leito fixo operado de forma contínua. Quando avaliado em relação a produção das três ciclodextrinas principais, o derivado cuja imobilização da enzima ocorreu via grupamento amino, evidenciou a possibilidade de modulação da produção apenas variando as condições de reação. α- e β-CD foram produzidas preferencialmente em pH 8,0 e 2 min (3,44 mg mL-1 e 3,51 mg mL-1, respectivamente), enquanto que pH mais ácido (4,0) e maior tempo de reação (141 min) favoreceram a formação de γ-CD (3,35 mg mL-1), com baixa formação α-CD (0,75 mg mL-1). Por fim, os resultados deste estudo evidenciam a importância da imobilização da CGTase para a estabilização de sua estrutura a fim de aplicá-la em sistemas contínuos de produção de CDs onde é possível modular o perfil dos produtos gerados em função das condições de reação, aumentando assim a produtividade do biocatalisador. / Cyclodextrin glycosyltransferase (CGTase) is the only enzyme capable of catalyzing the cyclization reaction from the starch and thus forming cyclic oligosaccharides known as cyclodextrins (CDs). Through this reaction, is produced a mixture of α-, β- and γ-CD containing, 6, 7 and 8 glucose residues respectively. Cyclodextrins (CD) have been attracting considerable attention because of its great potential for application in various areas of industry. This potential is provided by its conical structure with hydrophobic interior, capable of encapsulating solids, liquids and gases, changing important features and protecting them. In this work, the immobilization of CGTase in mesoporous silica was studied in a way directed to cysteines present on its surface, altering the exposure of the active site. The connection via native cysteine of the protein increased by four times the efficiency of immobilization compared to amino groups connection. The binding of amino groups, however, showed greater enzymatic activity in wider ranges of temperature and pH, and higher operational stability, while maintaining 100 % of its activity after 200 h of continuous reaction at 60 °C and pH 4. Although showing less stable connection, the derivative obtained by disulfide bond retained 40 % of the initial activity for 200 h and then, the support could be reloaded and reused for the same period. Developed supports showed satisfactory stability, enabling the use of the derivative assets in a packed bed reactor and operated continuously. It was demonstrated the possibility of modulating the CDs production just varying the reaction conditions, using the derivative of which the enzyme immobilization occurred via amino group, to evaluate the production of three main cyclodextrins. α- and β-CD were produced preferentially at pH 8.0 and 2 min (3.44 mg mL-1 and 3.51 mg mL-1, respectively), whereas the more acid pH (4.0) and longer reaction (141 min) favored the formation of γ-CD (3.35 mg mL-1 and 0.75 mg mL-1 of α-CD). Finally, the results of this study show the importance of the immobilization of CGTase to the stabilization of its structure in order to apply it in continuous CD production systems, where it is possible to modulate the profile of the products generated as a function of the reaction conditions, thus increasing the productivity of the biocatalyst.

Biodiesel is the most successful drop-in biofuel used in transportation. It can reduce GHG emissions in transportation by 50 to 90% depending on the type of feedstock used. Waste cooking oils and fats containing free fatty acids (FFA) are less expensive feedstocks for biodiesel production than refined vegetable oils. The major issue that limits the use of these oils as feedstock is the interference of FFAs with widely used base catalyzed reaction processes. The FFAs consume base catalyst, produce water of neutralization and form soaps that create emulsions downstream in the process reducing process yields. There is an important need to develop technologies that reduce the FFA content in these oils to below 0.5 wt%; the accepted limit for a feedstock to be processed by the base catalysed reaction. Enzymes are an efficient and environmentally friendly catalyst for FFA esterification. However, they are prone to deactivation with methanol and also catalyze the hydrolysis of esters and triglycerides to FFA. Using them to pre-treat oils and fats remains a challenge: in the presence of water, enzymes can readily produce FFAs from lipids. The objective of this work was to investigate two enzymatic processes to pre-treat acidic oil below the FFA requirement of 0.5 wt%. In this study, two different continuous systems, a packed bed reactor (PBR) and membrane reactor (MR) were used in FFA enzymatic esterification to meet the 0.5 wt% requirement, improve the reusability of enzymes and reduce catalyst cost. The esterification in the PBR was carried out using CALB immobilized on a new 2D/3D nanoplatelet support (TAN). The enzyme was covalently bonded to the TAN using a hydrophobic epoxy ligand. Acidic oil containing canola oil and 2.5 wt% FFA was used as the feedstock for the esterification. It was found that the FFA concentration met the quality specification of <0.5 wt% using CALB-TAN, while it did not using the commercial Novozym 435. The surface fluid velocity was found to have an effect on the removal of water from the PBR reactor. When the velocity was too low, water was retained in the reactor and the FFA conversion was low, when it was too high the reaction time for esterification was not sufficient. It was found that feed velocity of 3 to 6 x 10-5 m/s met the 0.5 wt% requirement. In the PBR, the use of CALB-TAN successfully eliminated the hydrolysis of TG and achieved the continuous esterification of FFA for 42 days. In the MR, acidic oil containing canola oil and 10 wt% FFA was used as the feedstock for the esterification. The enzyme adsorbed on the surface of the polar phase containing glycerol and water and was successfully retained in the reactor by a 0.2-micron ceramic membrane. The addition of glycerol increased the polarity of the dispersed phase in the reactor, bounded water, and retained the liquid enzyme in the reactor. However, the added glycerol in the reactor increased the operating pressure of the reactor. The operating pressure was reduced by adding biodiesel to the feedstock prior to treatment. The lowest level of FFA from the 10 wt% FFA feedstock was 0.68 wt%. This would require a second polishing step to reach the required 0.5 wt%. The PBR and MR using CALB are technologies that limit the hydrolysis at low FFA concentrations and are promising for the pre-treatment of acidic feedstocks in base catalysed biodiesel processes.

A ciclodextrina glicosiltransferase (CGTase) é a única enzima capaz de catalisar a reação de ciclização a partir do amido e, assim, formar oligossacarídeos cíclicos conhecidos como ciclodextrinas (CDs). Através desta reação é produzida uma mistura de α-, β- e γ-CD que, respectivamente, contém 6, 7 e 8 resíduos de glicose. As CDs têm atraído enorme atenção devido ao seu grande potencial de aplicação em diversas áreas da indústria. Potencial este proporcionado por sua estrutura cônica, com interior hidrofóbico, capaz de encapsular sólidos, líquidos e gases, conferindo propriedades importantes e protegendo-os. Neste trabalho foi estudada a imobilização de uma CGTase em sílica mesoporosa de forma direcionada às cisteínas presentes em sua superfície, alterando a exposição do sítio ativo. A ligação via cisteínas nativas da proteína aumentou em quatro vezes a eficiência da imobilização, quando comparada a ligação via grupamento amino. Esta, no entanto, apresentou maior atividade enzimática em faixas mais amplas de temperatura e pH, além de maior estabilidade operacional, mantendo 100 % de sua atividade após 200 h de reação contínua a 60 °C e pH 4. Ainda que apresentando menor estabilidade da ligação, o derivado obtido por ligação dissulfeto manteve 40 % da atividade inicial durante 200 h e então, o suporte pôde ser recarregado e reutilizado por igual período. Os suportes desenvolvidos apresentaram estabilidade satisfatória, possibilitando o uso do derivado imobilizado em reator de leito fixo operado de forma contínua. Quando avaliado em relação a produção das três ciclodextrinas principais, o derivado cuja imobilização da enzima ocorreu via grupamento amino, evidenciou a possibilidade de modulação da produção apenas variando as condições de reação. α- e β-CD foram produzidas preferencialmente em pH 8,0 e 2 min (3,44 mg mL-1 e 3,51 mg mL-1, respectivamente), enquanto que pH mais ácido (4,0) e maior tempo de reação (141 min) favoreceram a formação de γ-CD (3,35 mg mL-1), com baixa formação α-CD (0,75 mg mL-1). Por fim, os resultados deste estudo evidenciam a importância da imobilização da CGTase para a estabilização de sua estrutura a fim de aplicá-la em sistemas contínuos de produção de CDs onde é possível modular o perfil dos produtos gerados em função das condições de reação, aumentando assim a produtividade do biocatalisador. / Cyclodextrin glycosyltransferase (CGTase) is the only enzyme capable of catalyzing the cyclization reaction from the starch and thus forming cyclic oligosaccharides known as cyclodextrins (CDs). Through this reaction, is produced a mixture of α-, β- and γ-CD containing, 6, 7 and 8 glucose residues respectively. Cyclodextrins (CD) have been attracting considerable attention because of its great potential for application in various areas of industry. This potential is provided by its conical structure with hydrophobic interior, capable of encapsulating solids, liquids and gases, changing important features and protecting them. In this work, the immobilization of CGTase in mesoporous silica was studied in a way directed to cysteines present on its surface, altering the exposure of the active site. The connection via native cysteine of the protein increased by four times the efficiency of immobilization compared to amino groups connection. The binding of amino groups, however, showed greater enzymatic activity in wider ranges of temperature and pH, and higher operational stability, while maintaining 100 % of its activity after 200 h of continuous reaction at 60 °C and pH 4. Although showing less stable connection, the derivative obtained by disulfide bond retained 40 % of the initial activity for 200 h and then, the support could be reloaded and reused for the same period. Developed supports showed satisfactory stability, enabling the use of the derivative assets in a packed bed reactor and operated continuously. It was demonstrated the possibility of modulating the CDs production just varying the reaction conditions, using the derivative of which the enzyme immobilization occurred via amino group, to evaluate the production of three main cyclodextrins. α- and β-CD were produced preferentially at pH 8.0 and 2 min (3.44 mg mL-1 and 3.51 mg mL-1, respectively), whereas the more acid pH (4.0) and longer reaction (141 min) favored the formation of γ-CD (3.35 mg mL-1 and 0.75 mg mL-1 of α-CD). Finally, the results of this study show the importance of the immobilization of CGTase to the stabilization of its structure in order to apply it in continuous CD production systems, where it is possible to modulate the profile of the products generated as a function of the reaction conditions, thus increasing the productivity of the biocatalyst.

Please read the abstract in the dissertation. Copyright / Dissertation (MEng)--University of Pretoria, 2011. / Chemical Engineering / unrestricted

Modelos matemáticos oferecem grandes benefícios para a compreensão dos mecanismos envolvidos nos processos de tratamento de águas residuárias uma vez que fornecem interpretações e possibilitam previsões de desempenho, comparações de alternativas de tratamento, otimização de futuras plantas ou o aprimoramento das existentes, podendo subsidiar a elaboração de projetos em escala real. Em virtude disto, nesta pesquisa visou-se o desenvolvimento de um modelo bioquímico-matemático para descrever o processo de degradação da glicose em um reator anaeróbio de leito fixo com fluxo ascendente, com a resultante produção biológica de hidrogênio por meio do processo de fermentação. O desenvolvimento do modelo foi baseado em estudos sobre a cinética bioquímica e as características hidrodinâmicas do sistema. Os parâmetros de ajuste do modelo aos dados experimentais foram as constantes de velocidade das reações bioquímicas envolvidas na produção de hidrogênio. A calibração foi realizada manualmente buscando minimizar o desvio global. Para a determinação dos parâmetros foi utilizada a técnica de geração de números aleatórios com distribuição de freqüência uniforme e em seguida, o método de inversão de matrizes. O modelo matemático se revelou bastante adequado para a previsão do perfil de concentrações ao longo do reator, e possibilitou a representação das rotas de utilização da matéria orgânica. A reação de oxidação do ácido propiônico pelas bactérias acidogênicas produtoras de hidrogênio constitui a principal via de produção de \'H IND.2\' no sistema. / Mathematical models bring benefits to the understanding of mechanisms involved on wastewater treatment processes because they provide interpretations and make possible performance predictions, evaluation of design alternatives, optimization of future plants or the improvement to existing systems. Therefore, in this work a mathematical model to describe the glucose degradation process, with hydrogen production through the fermentation, in an upflow anaerobic packed-bed reactor is developed. The model equations were based on studies of biochemical kinetics and hydrodynamics features of the system. The parameters considered were the rates of the biochemical reactions involved in the hydrogen production. The calibration was made through the minimization of the global deviation. The parameters determination was obtained with the use of a technique of generation of aleatory numbers, and after that, the method of matrices inversion for the solution of the system of linear equations. The mathematical model developed showed to be adequate for the concentrations prediction along the reactor, and it made possible the representation of the routes of organic material utilization. The oxidation reaction of propionic acid is the main hydrogen production route in the reactor.

O hidrogênio é estudado como alternativa ao uso de combustíveis fósseis para geração de energia, uma vez que é um combustível renovável, apresenta alta concentração de energia por unidade de massa e não gera gases causadores do efeito estufa. Entre os processos de produção de hidrogênio destaca-se o processo fermentativo, pois é um processo de baixo custo quando comparado com outros processos e possibilita unir tratamento de efluente e geração de energia. Neste sentido, este trabalho teve como proposta estudar parâmetros envolvidos no processo de produção fermentativo do \'H IND.2\'. O trabalho envolveu três etapas. Na primeira etapa, foi estudada a produção de hidrogênio a partir de sacarose empregando reatores anaeróbios de leito fixo de fluxo ascendente. Na primeira fase, comparou-se o desempenho de diferentes matérias suportes (argila, carvão vegetal e polietileno) e tempos de detenção hidráulica (TDH) (0,5 e 2h). Na segunda fase, testaram-se diferentes porosidades (50, 75 e 91%) do leito de polietileno TDH de 0,5 h. Os resultados mostraram que TDHs menores e maiores porosidades promovem maiores e contínuas produções de \'H IND.2\'. Na segunda fase, avaliou-se a produção de \'H IND.2\' a partir de quatro inóculos: metanogênico tratamento termicamente e três provenientes de biomassa aderidas aos materiais suportes empregados na primeira etapa. Todos inóculos produziram \'H IND.2\'. Na terceira etapa, avaliou-se a viabilidade de produzir \'H IND.2\' a partir de diferentes águas residuárias (sacarose, esgoto sanitário, vinhaça e glicerina). Houve conversão de hidrogênio a partir de todas as águas residuárias e a vinhaça mostrou ser o efluente mais promissor para esta finalidade. As análises biológicas mostraram baixa diversidade de fungos e bactérias, porém todos associados com o processo de formação de \'H IND.2\'. A varredura dos parâmetros estudados neste trabalho proporcionou o entendimento do processo, assim como, o mapeamento das variáveis adequadas para o projeto e viabilidade da aplicação de reatores desenvolvidos para geração de hidrogênio. / The hydrogen obtained by fermentative production is studied as an alternative process to provide energy instead of fossil fuel application. Moreover, hydrogen is a renewable fuel, has high energy content per unit weight (122 kJ/g), generates clean energy without pollution and produces no greenhouse gases. The fermentative process has low cost when it is compared with traditional process and photosynthetic process, because hydrogen can be produced from wastewater by anaerobic treatment process. For that reason, the aim of this research was to study some parameters involved in the hydrogen production by fermentative process. Three steps were developed. In the first step, it was studied the hydrogen production from sucrose using up-flow anaerobic packed-bed reactor, this step was divide in two phases. In the first phase three support materials (clay beads, vegetal coal and polyethylene) and two hydraulic retention times (0.5 and 2 h) were tested. In the second phase three porosities (50, 75 and 91%) of polyethylene bed were tested. The results demonstrated that the low HRT and high porosities provided high hydrogen production, although, the support materials did not show significant difference in the hydrogen production and in the biomass developed. In the second phase, four inocula were used in order to produce hydrogen: thermal pre-treated methanogenic sludge; and the others three came from the reactors used in the first phase. All inocula were able to produce hydrogen. In the third step hydrogen production was obtained from three wastewaters (domestic wastewater, vinasse and glycerol) and a control (sucrose) in batch reactors. The wastewaters and control produced hydrogen and the vinasse showed the highest production. This research makes available the comprehension on the influence of the different parameters in processes projected for hydrogen production and it makes viable to apply in full-scale.

Naphthenic acids (NAs) comprise a complex mixture of alkyl-substituted acyclic and cycloaliphatic carboxylic acids. NAs are present in wastewaters at petroleum refineries and in the process waters of oil sands extraction plants where they are primarily retained in large tailing ponds in the Athabasca region of Northern Alberta. The toxicity of these waters, primarily caused by NAs, dictates the need for their treatment.Bioremediation is considered as one of the most cost-effective approaches for the treatment of these wastewaters. Ex-situ bioremediation conducted in a bioreactor optimizes the microbial growth and activity by controlling environmental conditions resulting in efficient conversion of the contaminants to less harmful compounds. In this work, a circulating packed bed bioreactor (CPBB), with improved mixing, mass transfer and biomass hold-up has been used to study biodegradation of several model NA compounds: namely trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA), a mixture of cis- and trans- 4-methyl-cyclohexane acetic acid (4MCHAA), and octanoic acid as well co-biodegradation of these naphthenic acids with octanoic acid, using a mixed culture developed in our laboratory. The biodegradation rates achieved for trans-4MCHCA in the CPBB are far greater than those reported previously in the literatures. The maximum biodegradation rate of trans-4MCHCA observed during batch operation was 43.5 mg/L-h, while a rate of 209 mg/L-h was achieved during continuous operation. Although cis-4MCHAA is more resistant to biodegradation when compared with trans-4MCHCA, the experimental results obtained from this study indicated both isomers were effectively biodegraded in the CPBB, with the maximum biodegradation rates being as high as 2.25 mg/L-h (cis-4MCHAA) and 4.17 mg/L-h (trans-4MCHAA) during batch operations and 4.17 mg/L-h(cis-4MCHAA) and 7.80 mg/L-h (trans-4MCHAA) during the continuous operation. Optimum temperature for biodegradation of 4MCHAA was determined as 25 aC. Furthermore, the biodegradation rate of single ring NAs (trans-4MCHCA and 4MCHAA) were found to be significantly improved through utilization of octanoic acid as a co-substrate. For example, the maximum biodegradation rate of trans-4MCHCA obtained during batch operation with the presence of octanoic acid was 112 mg/L-h, which was 2.6 times faster than the maximum value of 43.5 mg/L-h when trans-4MCHCA was used as a sole substrate. Similarly, the highest biodegradation rates of cis-4MCHAA and trans-4MCHAA were 16.7 and 28.4 mg/L-h in the presence of octanoic acid, which were 7.4 and 6.8 times higher than the maximum rates of 2.25 and 4.17 mg/L-h in the absence of octanoic acid.

Naphthenic acids (NAs) comprise a complex mixture of alkyl-substituted acyclic and cycloaliphatic carboxylic acids. NAs are present in wastewaters at petroleum refineries and in the process waters of oil sands extraction plants where they are primarily retained in large tailing ponds in the Athabasca region of Northern Alberta. The toxicity of these waters, primarily caused by NAs, dictates the need for their treatment.Bioremediation is considered as one of the most cost-effective approaches for the treatment of these wastewaters. Ex-situ bioremediation conducted in a bioreactor optimizes the microbial growth and activity by controlling environmental conditions resulting in efficient conversion of the contaminants to less harmful compounds. In this work, a circulating packed bed bioreactor (CPBB), with improved mixing, mass transfer and biomass hold-up has been used to study biodegradation of several model NA compounds: namely trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA), a mixture of cis- and trans- 4-methyl-cyclohexane acetic acid (4MCHAA), and octanoic acid as well co-biodegradation of these naphthenic acids with octanoic acid, using a mixed culture developed in our laboratory. The biodegradation rates achieved for trans-4MCHCA in the CPBB are far greater than those reported previously in the literatures. The maximum biodegradation rate of trans-4MCHCA observed during batch operation was 43.5 mg/L-h, while a rate of 209 mg/L-h was achieved during continuous operation. Although cis-4MCHAA is more resistant to biodegradation when compared with trans-4MCHCA, the experimental results obtained from this study indicated both isomers were effectively biodegraded in the CPBB, with the maximum biodegradation rates being as high as 2.25 mg/L-h (cis-4MCHAA) and 4.17 mg/L-h (trans-4MCHAA) during batch operations and 4.17 mg/L-h(cis-4MCHAA) and 7.80 mg/L-h (trans-4MCHAA) during the continuous operation. Optimum temperature for biodegradation of 4MCHAA was determined as 25 aC. Furthermore, the biodegradation rate of single ring NAs (trans-4MCHCA and 4MCHAA) were found to be significantly improved through utilization of octanoic acid as a co-substrate. For example, the maximum biodegradation rate of trans-4MCHCA obtained during batch operation with the presence of octanoic acid was 112 mg/L-h, which was 2.6 times faster than the maximum value of 43.5 mg/L-h when trans-4MCHCA was used as a sole substrate. Similarly, the highest biodegradation rates of cis-4MCHAA and trans-4MCHAA were 16.7 and 28.4 mg/L-h in the presence of octanoic acid, which were 7.4 and 6.8 times higher than the maximum rates of 2.25 and 4.17 mg/L-h in the absence of octanoic acid.

The objective of this work was to develop a novel enzyme immobilization scheme for supported lipase sol-gels and to evaluate the potential of the immobilized biocatalyst for the production of biodiesel in a packed bed reactor. Two sources of lipase (EC 3.1.1.3 triacylglycerol hydrolase) were used in this study and the transesterification of methanol and triolein to produce glycerol and methyl oleate was used as a model reaction of biodiesel production. A commercially available form of immobilized lipase, Novozym® 435, was used as a basis for comparison to the literature. Upon establishing a lipase sol-gel formulation technique, the experimental methodology for the transesterification reaction using Novozyme® 435 was developed. Subsequently, a series of inert materials were considered based on their suitability as supports for immobilized lipase sol-gels and the synthesis of methyl oleate. The value of a supported lipase sol-gel is to improve the activity and stability of the enzyme and develop an immobilized biocatalyst that is practical for use under packed bed reactor conditions. Of the six support materials considered (6-12 mesh silica gel, Celite® R633, Celite® R632, Celite® R647, anion exchange resin, and Quartzel® felt), the diatomaceous earth supports (Celite® R633, R632 and R647) exhibited high enzymatic activity, were thermally stable, and possessed high sol-gel adhesion. From the three types of diatomaceous earth considered, Celite® R632 supported lipase sol-gels were identified as the most promising supported lipase sol-gels for methyl oleate production via transesterification. Upon further evaluation, the Celite® R632 lipase sol-gels were found to achieve high methyl oleate percent conversions, glycerol-water absorption was only significant at glycerol levels higher than 75%, and the immobilized lipase had high stability upon storage at 4°C for 1.5 years. To determine the effects of methanol and glycerol inhibition as well as temperature on the reaction kinetics, a ping-pong bi-bi kinetic model was developed and validated over a range of methanol concentrations and temperatures. The optimal methanol concentration for the conditions tested was in the range of 1.3 M to 2.0 M, and increased with increasing temperature. The model developed was consistent with the experimental data and confirmed that glycerol inhibition and the presence of products had significant effects on the reaction kinetics. The methyl oleate production capabilities of the Celite® supported lipase sol-gel were investigated using a packed bed reactor and compared with Novozym® 435 under similar operating conditions. A kinetic and mass transfer based model was developed for the reactor system using a novel efficiency correlation to account for the effect of glycerol on the enzymatic activity. Increasing the flow rate (1.4 mL/min to 20 mL/min) increased the reaction rate, presumably due to the reduction of the glycerol inhibition effect on the immobilized biocatalyst. The Celite® supported lipase sol-gel was found to have superior performance over Novozym® 435 both under batch stirred tank reaction conditions and in a packed bed reactor (83% conversion for Celite® sol-gel vs. 59% conversion for Novozym® 435 at 20 mL/min in the packed bed reactor). Based on the results obtained, Celite® supported lipase sol-gels exhibited good performance for the transesterification of triolein with methanol to produce methyl oleate in both batch and packed bed reactors, and warrant further exploration for the enzymatic production of biodiesel.