Continuous Packed-bed Reactor Research Articles

Role of Glutaraldehyde in Imparting Stability to Immobilized β-Galactosidase Systems

ABSTRACT This review article highlights the role of glutaraldehyde as a matrix activator/stabilizer in imparting higher operational and thermal stability to β-galactosidase (βG) for biotechnological applications. Glutaraldehyde has been used extensively as a crosslinking agent as well as for functionalization of matrices to immobilize β-galactosidase. Immobilized β-galactosidase systems (IβGS) obtained as a result of glutaraldehyde treatment has been employed to hydrolyze whey and milk lactose in batch reactors, continuous packed-bed and fluidized bed reactors under various operational conditions. Moreover, these IβGS have also been utilized for the production of galactooligosaccharides in food, dairy and fermentation industries. It was observed that glutaraldehyde provided remarkable stability to immobilize βG against various physical/chemical denaturants, thus enhancing thermal/operational stability and rendering it more suitable for repeated utilization in industrial scale operations.

Polyaniline stabilization of magnetic particles and immobilization of α-amylase

Magnetic particles (MAG), obtained by standard procedure of coprecipitation of Fe2+and Fe3+ in an excess of ammonia, and polyaniline modified magnetic particles MAG-PANI were used as carriers for immobilization of ?-amylase from Bacillus licheniformis. The formation of a polyaniline layer (PANI) on MAG particles was achieved by chemical polymerization of aniline. Immobilization was carried out by adsorption, as a simple, inexpensive and fast method that allows retention of a large portion of the initial activity of the immobilized enzyme. FTIR spectroscopy was used to characterize the obtained particles and to confirm changes dueto formation of a PANI layer and conjugation of ?-amylase on the particle surfaces. Particle size distribution was bimodal and three-modal for MAG and MAG-PANI, respectively. Appearance of a fraction of smaller MAG-PANI particles than MAG particles could be attributed to the formation of PANI particles without the MAG core. Measured values of Zeta potential for MAG-PANI were higher as compared to MAG indicating stabilization of particles in the presence of PANI. Relevant kinetic parameters for immobilized enzyme were determined from the Hanes plot. The apparent Km constant was 1.91 and 1.48 g L?1 for MAG-A and MAG-PANI-A, respectively, while ??m was 0.19 g L?1 min?1 for MAG and 0.32 g L?1 min?1 for MAG-PANI. The obtained values of Km indicated that modification of MAG by PANI enhanced kinetic properties of the immobilized enzyme. Moreover, the modification of MAG by PANI showed the increase in both pH and thermal stabilities of the immobilized enzyme. Studies of the operational activity of the immobilized enzyme on MAG-PANI have shown that 98.8% of starch was hydrolyzed over 20.0 min. In the first cycle in the packed bed reactor operated in a recycling mode, but approximately five times longer period was required to hydrolyze 93.5 of starch in the fifth cycle. In the continuous packed bed reactor without recycling, the degree of starch hydrolysis was not changed significantly during 4 h and was 88.8?1.6%, whereas the half-life of the biocatalyst was 6.2 h. Although coating MAG particles with a polyaniline offers many advantages, the main disadvantage is possible appearance of residues of aniline monomers and dimmers. The potential toxicity of these residues requires precise composition analysis of the product of starch hydrolysis catalyzed by ?-amylase adsorbed onto MAG-PANI.

Biodiesel production in a continuous packed bed reactor with recycle: A modeling approach for an esterification system

The aim of this work is to propose and to validate a dynamical model for an esterification reaction that was carried out in a relatively new configuration for biodiesel production process: a packed bed reactor with input, output, and recycle. More specifically, the reagents of the esterification process were free fatty acids (FFA) contained in canola oil and low cost methanol (LCM), whereas a commercial cation exchange resin (Purolite CT725) was used as a solid-acid catalyst. The effects of both the LCM volumetric inflow rate and the inflow FFA molar fraction were investigated. The dynamical model was built considering the following assumptions: 1) the reactor was modeled as a CSTR due to the high ratio of recycling volumetric flow to reactor volumetric inflow and 2) the kinetic expression in the model is written in terms of activity coefficients in the light of the non-ideal behavior of the esterification reaction. A satisfactory agreement between the experimental data and the proposed model was obtained. Thus, the resulting model may be advised as a valuable tool for the analysis, control, and optimization of continuous packed bed reactors where the esterification of FFA in the presence of solid acid catalyst is carried out to produce biodiesel.

Gas phase synthesis of isopropyl chloride from isopropanol and HCl over alumina and flexible 3-D carbon foam supported catalysts

Isopropyl chloride synthesis from isopropanol and HCl in gas phase over ZnCl2 catalysts supported on Al2O3 as well as flexible carbon foam was studied in a continuous reactor. A series of catalytic materials were synthesised and characterised by BET, XPS, SEM, TEM, XRD and NH3-TPD methods. Catalytic activity tests (product selectivity and conversion of reactants) were performed for all materials and optimal reaction conditions (temperature and feedstock flow rates) were found. The results indicate that the highest yield of isopropyl chloride was obtained over 5wt.% ZnCl2 on commercial Al2O3 (No. II) (95.3%). Determination of product mixture compositions and by-product identification were done using a GC-MS method. Carbon foam variant catalyst, 5wt.% ZnCl2/C, was found to perform best out of the carbon-supported materials, achieving ∼75% yield of isopropyl chloride. The kinetic model describing the process in a continuous packed bed reactor was proposed and kinetic parameters were calculated. The activation energy for the formation of isopropyl chloride reaction directly from isopropanol and HCl was found to be ∼58kJ/mol.

Treatment of wastewater by mixed bacterial consortium in continuous reactors packed with solid waste

Phenol is one of the priority pollutants as declared by EPA (USA). Very few comparative studies have been carried out with continuous packed bed reactors (PBR) for bacterial degradation of phenol and applying the result in real time situation. The present study compared the performance of a co-current and a counter-current continuous PBR in degrading phenol by a mixed consortium of bacteria isolated from the East Calcutta Wetlands based on both rate of phenol degradation and phenol removal efficiency. Different process parameters like air flow rate, hydraulic retention time and temperature were varied for both the systems. Performance of the co-current continuous PBR was found to be more efficient. To validate the performance of this system in actual application in industry a real time phenolic industrial effluent was fed to this system. Phenol degradation rate was 1.43mg/lmin and the phenol removal efficiency of this co-current continuous PBR was 72.85%.

Removal of phenol from oil/gas produced water using supercritical water treatment with TiO2 supported MnO2 ctalyst

MnO2 catalyst supported on TiO2 was synthesized and evaluated for removal of phenol in supercritical water. Synthesized catalysts were characterized using temperature programmed reduction, pulse chemisorption, and X-ray powder diffraction. Catalyst activity for phenol conversion was evaluated in a continuous packed bed reactor at supercritical water conditions by analyzing gaseous and liquid products. Process variables evaluated include O2 stream concentration and Mn catalyst loading. Both variables had positive effects on phenol conversion. The process achieved complete conversion of phenol at oxygen ratio of 5 based on complete phenol combustion stoichiometry. Increasing catalyst Mn loading increased its active site concentration, enhancing the contribution of heterogeneous reaction kinetics for supercritical water oxidation (SCWO) of the phenol. A phenol conversion of 70% was reached at 12% (w/w) Mn in the catalyst with oxygen ratio of 1.

Continuous Packed Bed Reactor with Immobilized β-Galactosidase for Production of Galactooligosaccharides (GOS)

The β-galactosidase from Bacillus circulans was covalently attached to aldehyde-activated (glyoxal) agarose beads and assayed for the continuous production of galactooligosaccharides (GOS) in a packed-bed reactor (PBR). The immobilization was fast (1 h) and the activity of the resulting biocatalyst was 97.4 U/g measured with o-nitrophenyl-β-d-galactopyranoside (ONPG). The biocatalyst showed excellent operational stability in 14 successive 20 min reaction cycles at 45 °C in a batch reactor. A continuous process for GOS synthesis was operated for 213 h at 0.2 mL/min and 45 °C using 100 g/L of lactose as a feed solution. The efficiency of the PBR slightly decreased with time; however, the maximum GOS concentration (24.2 g/L) was obtained after 48 h of operation, which corresponded to 48.6% lactose conversion and thus to maximum transgalactosylation activity. HPAEC-PAD analysis showed that the two major GOS were the trisaccharide Gal-β(1→4)-Gal-β(1→4)-Glc and the tetrasaccharide Gal-β(1→4)-Gal-β(1→4)-Gal-β(1→4)-Glc. The PBR was also assessed in the production of GOS from milk as a feed solution. The stability of the bioreactor was satisfactory during the first 8 h of operation; after that, a decrease in the flow rate was observed, probably due to partial clogging of the column. This work represents a step forward in the continuous production of GOS employing fixed-bed reactors with immobilized β-galactosidases.

Aspergillus oryzae Lipase‐Catalyzed Synthesis of Dioleoyl; Palmitoyl‐Rich Triacylglycerols in Two Reactors

AbstractDioleoyl; palmitoyl‐rich triacylglycerols (OPO‐rich TAG) were synthesized through Aspergillus oryzae lipase (AOL)‐catalyzed acidolysis of palm stearin with commercial oleic acid by a one‐step process in a stirred tank reactor and continuous packed bed reactor to evaluate the feasibility of using immobilized AOL. AOL was found to be valuable for the synthesis of OPO‐rich TAG when compared with commercial lipase from Thermomyces lanuginose (Lipozyme® TL IM; Novozymes A/S, Bagsvaerd, Denmark). The C52 (triglycerides with a carbon number of 52, stands for OPO, OPL, LPL and their isomers) content of AOL was higher (45.65 %), and the intensity of treatment (IOT: lipase amount × reaction time/TAG amount) of AOL was just 6.25 % of that of Lipozyme® TL IM under similar reaction conditions in the stirred tank reactor. Response surface methodology were used to optimize the reaction conditions of the AOL‐catalyzed acidolysis is reaction in the packed bed reactor. The optimal point for the set of experimental conditions generated were as follows: residence time 3.0 h; temperature 62.09 °C; substrate molar ratio 7.13 mol/mol. The highest C52 content obtained was 48.60 ± 2.36 %, with 57.46 ± 1.72 % total palmitic acid at the sn‐2 position and 74.21 ± 2.45 % oleic acid at the sn‐1,3 positions. The half‐life of AOL was 24 h in the stirred tank reactor and 140 h in the packed bed reactor. The immobilized AOL achieved similar conversion and selectivity to commercial lipases for the catalyzed synthesis of OPO‐rich TAG and may offer a cheaper alternative.

Biodiesel production by methanolysis of waste lard from piglet roasting over quicklime

Waste lard from piglet roasting and quicklime (basically CaO) as a priceless fatty feedstock and a cheap solid catalyst, respectively were tested for the biodiesel production by methanolysis in a batch stirred reactor at moderate reaction temperatures (40–60°C) for the kinetic study. For comparison, unheated and heated pork lards, as well as pure CaO, were also included in this study. The mass transfer limitation was observed in the initial period of all methanolysis reactions. The kinetic model combining the changing- and first-order reaction rate laws with respect to triacylglycerols and fatty acid methyl esters (FAMEs), respectively was verified for all three lardy feedstocks and both catalysts. The catalytic activity of quicklime was the same as that of pure CaO. The activation energy was demonstrated to be independent of the feedstock and the catalyst (59.1±0.6kJ/mol), but the waste lard reacted faster than the unheated and heated pork lards. At the methanol-to-lard molar ratio of 6:1, the catalyst amount of 5% (based on the lard weight) and the reaction temperature of 60°C, a high FAME concentration in the final ester products (97.5%) within 60min were achieved with the waste lard and quicklime in two consecutive batches. The same kinetic model was applicable in a continuous packed-bed tubular reactor filled with quicklime bits (2.0–3.15mm) at the methanol-to-waste lard molar ratio of 6:1, the reaction temperature of 60°C and the residence time of 1h. Under these conditions, the biodiesel yield was 97.6%, while the FAME concentration in the biodiesel product was 96.5%.

Continuous enzymatic biodiesel production from coconut oil in two-stage packed-bed reactor incorporating an extracting column to remove glycerol formed as by-product.

The transesterification of coconut oil with ethanol catalyzed by Burkholderia cepacia lipase immobilized on polysiloxane-polyvinyl alcohol was performed in a continuous flow. The experimental design consisted of a two-stage packed-bed reactor incorporating a column with cationic resin (Lewatit GF 202) to remove the glycerol formed as by-product and the reactor performance was quantified for three different flow rates corresponding to space-times from 10 to 14h. The influence of space-time on the ethyl ester (FAEE) concentrations, yields and productivities was determined. The reactor operation was demonstrated for space-time of 14h attaining FAEE concentrations of 58.5±0.87wt%, FAEE yields of 97.3±1.9% and productivities of 41.6 ±1.0mgesterg medium (-1) h(-1). Biodiesel purified samples showed average kinematic viscosity values of 5.5±0.3mm(2)s(-1) that meet the criteria established by the American National Standard ASTM (D6751). The immobilized lipase was found to be stable regarding its morphological and catalytic characteristics, showing half-life time (t 1/2) around 1540h. The continuous packed-bed reactor connected in series with simultaneous glycerol removal has a great potential to attain high level of transesterification yields, raising biodiesel productivity.

Chitosan beads from microbial and animal sources as enzyme supports for wine application

Chitosan beads from a microbial source, i.e. Aspergillus niger (An), were produced by precipitation method for the first time and compared with supports prepared from an animal source, i.e. shellfish derived chitosan with three different molecular weights (low (LMW), medium (MMW) and high (HMW)). The produced beads were used as enzyme carriers to be applied in a continuous packed-bed reactor (PBR) for white wine protein stabilization.For this purpose, the beads were crosslinked with glutaraldehyde (GDH) and stem bromelain was immobilized on the carrier surface as a model enzyme, following two different procedures (i.e., crosslinking with glutaraldehyde (GDH) and direct linkage (DL)).Drop-like beads with an average diameter of 3.0–3.5 mm and a moisture content of 86–94% were obtained. The morphology of the produced beads in dried state, in terms of shape and surface, was studied by means of a scanning electron microscope (SEM), evidencing the obtainment of nearly spherical or oval particles. The efficacy of the crosslinking procedure and of bromelain immobilization was demonstrated by means of SEM investigation and infrared spectroscopy (FT-IR) analysis, revealing a rougher surface. Various initial protein concentrations ranging between 0.45 and 18.00 mgBSAeq mL−1 were tested in order to identify the optimal amount and to evaluate the influence of the initial concentration on the total protein loading.Stem bromelain proved to be more active when immobilized by DL on An beads and was efficient in reducing white wine hazing potential continuously, as verified with a laboratory bench-scale PBR.

Assessment of methods of detection of water estrogenicity for their use as monitoring tools in a process of estrogenicity removal

ABSTRACTMethods of monitoring of estrogenicity in water were gathered, compared, and tested within the context of their practical use as measurement and design tools, in the development of a process of degradation of estrogenic endocrine disruptors. In this work, the focus was put on in vitro assays, with the use of analytical techniques as additional analysis when possible. Practically, from a literature review, four methods that seemed most suitable to practical use required in a process development were tested: the Yeast Estrogen Screen assay, the Lyticase-assisted Yeast Estrogen Screen assay (LYES), the MMV-LUC assay and the HPLC-UV analytical method. Dose–response curves in response to estrogenic standard 17β-estradiol were compared. Bisphenol A estrogenicity was measured by the methods as well. The model for the calculation of estradiol equivalents as measurements units was adapted. The methods were assessed in terms of ranges of detection, time of experiment, cost, ease of the experiment, reproducibility, etc. Based on that assessment, the LYES assay was selected and successfully applied to the monitoring of estrogenicity removal from 17β-estradiol and bisphenol A. More precisely, the bioassay allowed the acquisition of kinetic curves for a laboratory-scaled process of estrogenicity removal by immobilized enzymes in a continuous packed-bed reactor. The LYES assay was found to have a real methodological potential for scale-up and design of a treatment process. The HPLC-UV method showed good complementarity with the LYES assay for the monitoring of bisphenol A concentrations in parallel with estrogenicity, reporting no significant estrogenicity from degradation byproducts, among others.

Different reaction behaviours of the light and heavy components of bio-oil during the hydrotreatment in a continuous pack-bed reactor

This study aims to investigate the hydrotreatment of bio-oil in a continuous packed-bed reactor at around 375°C and 70bar. The bio-oil was produced from the grinding pyrolysis of mallee wood in a grinding pyrolysis pilot plant. Our results indicate that the lighter and heavier components in the same bio-oil could behave very differently. Their behaviour can be affected very significantly by the overall bio-oil liquid hourly space velocity. While the residence time of the light species that evaporate instantly could be very short, the residence time of heavy species passing through the catalyst bed in the form of liquid could be very long. When a commercial pre-sulphided NiMo/Al2O3 catalyst came into contact with the heavy bio-oil species, significant exothermic reactions would take place, which result in the deactivation of hyperactive sites in the catalyst. The NiMo/Al2O3 catalyst used was less active in hydrotreating the heavier bio-oil species than in hydrotreating the lighter bio-oil species. However, even at very low extents of hydrotreatment, the bio-oil structure and properties, e.g. coking propensity, could be drastically improved.

Lignocellulosic ethanol production employing immobilized Saccharomyces cerevisiae in packed bed reactor

Most of ethanol production processes are limited by lower ethanol production rate and recyclability problem of ethanologenic organism. In the present study, immobilized co-fermenting Saccharomyces cerevisiae GSE1618 was employed for ethanol fermentation using rice straw enzymatic hydrolysate in a packed bed reactor (PBR). The immobilization of S. cerevisiae was performed by entrapment in Ca-alginate for optimization of ethanol production by varying alginic acid concentration, bead size, glucose concentration, temperature and hardening time. Remarkably, extra hardened beads (EHB) immobilized with S. cerevisiae could be used up to repeated 40 fermentation batches. In continuous PBR, maximum 81.82 g L−1 ethanol was obtained with 29.95 g L−1 h−1 productivity with initial glucose concentration of 180 g L−1 in feed at dilution rate of 0.37 h−1. However, maximum ethanol concentration of 40.33 g L−1 (99% yield) with 24.61 g L−1 h−1 productivity was attained at 0.61 h−1 dilution rate in fermentation of un-detoxified rice straw enzymatic hydrolysate (REH). At commercial scale, EHB has great potential for continuous ethanol production with high productivity using lignocellulosic hydrolysate in PBR.

Preparation of Diacylglycerol-enriched Rice Bran Oil by Lipase-catalyzed Deacidification in Packed-bed Reactors by Continuous Dehydration.

Diacylglycerol-enriched rice bran oil (RBO-DAG) was produced by deacidification of high-acid rice bran oil (RBO) with glycerol (Gly) using Lipozyme RM IM by continuous dehydration by combination of two enzyme columns (column 1 and 3, used for deacidification) with one molecular sieves column (column 2, used for dehydration). The conditions for three columns were respectively optimized. Response surface methodology (RSM) was used to optimize the conditions of column 1. The content of DAG and conversion of free fatty acid (FFA) were used as indicators and the effects of the enzyme load (8-12 g), flow rate (0.3-0.6 mL/min), substrate molar ratio (4-6) and reaction temperature (55-75°C) were investigated. The content of DAG and conversion of FFA were significantly correlated to the flow rate and substrate molar ratio. Most desirable conditions of the reaction with respect to the maximal DAG content and FFA conversion was attained under the residence time of 40 min, substrate molar ratio of 5.52 (Gly: RBO) and temperature of 66°C. The conditions for column 2 were investigated by varying molecular sieves load and flow rate, and the maximal dehydration rate of 85.22% was obtained under the optimal conditions. For column 3, the optimum conditions were obtained as: flow rate, 0.2mL/min; temperature, 65°C, and the content of DAG and FFA were 38.99% and 3.04%, respectively under these conditions. The catalytic activity of the lipase was stable in twelve continuous operations with 83.22% of its original ability, demonstrating its potential in the continuous packed-bed reactors (PBRs) system. These results showed that packed-bed reactors combined with continuous deacidification and dehydration in one system had great value in industrial production for high-acid RBO with the improved conversion rate.

High-yield production of enantiopure 2-hydroxy-2-(2′-chlorophenyl) acetic acid by long-term operation of a continuous packed bed reactor

We recently described the development of a versatile and efficient esterase (rPPE01W187H) for the preparation of enantiopure 2-hydroxy acids. Herein, a primary amino-functionalized resin (ESR-1) was selected for immobilizing rPPE01W187H, and the resulting immobilized enzyme, rPPE01W187H@ESR-1, exhibited notably enhanced stability. No obvious inactivation was observed for rPPE01W187H@ESR-1 following its incubation at 30°C for 1440h, whereas the half-life of the free enzyme was only 50.2h under the same conditions. A continuous process was subsequently developed using rPPE01W187H@ESR-1 in a packed bed reactor, which allowed for the immobilized enzyme to be conveniently recycled. The space-time yield for biocatalytic resolution of 2-acetoxy-2-(2′-chlorophenyl)acetate in this packed bed reactor reached as high as 3.34 kgL−1d−1 following the optimization of the critical process parameters, including the initial pH, H:D ratio and flow direction. Further investigation of the operational stability indicated that the enzymatic process could be continuously operated for at least 42d with approximately 50% conversion and nearly perfect optical purity, giving an outstanding total turnover number of 1.13×107 for rPPE01W187H. The continuous, long-term and high-performance manufacturing process developed in this study therefore highlights the potential feasibility of using rPPE01W187H for the large-scale production of optically pure chiral 2-hydroxy acids.

Immobilised native plant cysteine proteases: packed-bed reactor for white wine protein stabilisation.

This research presents a feasibility study of using a continuous packed-bed reactor (PBR), containing immobilised native plant cysteine proteases, as a specific and mild alternative technique relative to the usual bentonite fining for white wine protein stabilisation. The operational parameters for a PBR containing immobilised bromelain (PBR-br) or immobilised papain (PBR-pa) were optimised using model wine fortified with synthetic substrate (Bz-Phe-Val-Arg-pNA). The effectiveness of PBR-br, both in terms of hazing potential and total protein decrease, was significantly higher than PBR-pa, in all the seven unfined, white wines used. Among the wines tested, Sauvignon Blanc, given its total protein content as well as its very high intrinsic instability, was selected as a control wine to evaluate the effect of the treatment on wine as to its soluble protein profile, phenolic composition, mineral component, and sensory properties. The treatment in a PBR containing immobilised bromelain appeared effective in decreasing both wine hazing potential and total protein amount, while it did not significantly affect the phenol compounds, the mineral component nor the sensory quality of wine. The enzymatic treatment in PBR was shown to be a specific and mild technique for use as an alternative to bentonite fining for white wine protein stabilisation.

Simultaneous Continuous Removal of Cr(VI) and Phenol from Binary Synthetic Simulated Waste Water in Tea Waste Packed Bed Column: Kinetic Modeling

In this study, simultaneous co-adsorption of Cr(VI) and phenol was carried out in a continuous packed-bed reactor packed with tea waste biomass. The experiments were carried out using binary synthetic simulated solution containing 100 mg/L of Cr(VI) and 50 mg/L of phenol. The binary synthetic solution was passed through the packed-bed reactor at different flow rates (5.46, 8.19, and 16.3 mL/min) and bed height (36, 54, 72, and 93 cm). The pH of the binary synthetic solution was 5 as the maximum simultaneous percentage removal of Cr(VI) and phenol was obtained at this pH reported in our previous study.[1] The effects of flow rate and bed depth onto the simultaneous percentage removal of Cr(VI) and phenol were investigated. According to the average percentage error (ϵ%) and average relative error (ARE %) calculated for various kinetic models reveal that Yoon–Nelson model for Cr(VI) and Thomas model for phenol best describes the experimental data. The maximum adsorption capacity of tea waste biomass in a packed-bed reactor for Cr(VI) and phenol was 57.04 and 27.96 mg/g, respectively. The packed bed of the column was regenerated using 2 N NaOH.

Robust kinetic modeling of heterogeneously catalyzed free fatty acids esterification in monophasic liquid/solid packed bed reactor: rival model discrimination

Biodiesel production could be economically sustainable if raw oils, i.e., waste cooking oil or oils with a high acid content, are used for its production. However, the high content of free fatty acid (FFA) of these oils makes necessary a pretreatment before the transesterification step. Esterification using methanol and a heterogeneous catalyst should be very convenient because this reaction permits to decrease FFA content by producing simultaneously methyl esters, i.e., biodiesel. This technology was applied in a continuous packed bed reactor for the deacidification of sunflower oil, using Amberlyst 46 as heterogeneous acid catalyst at pressure of 6 bar and temperature in the range of 54–95 °C. An amount of methanol five times greater than the stoichiometric was added to sunflower oil, in order to shift the reaction equilibrium but avoiding the formation of a double liquid phase. Two different kinetic models were considered: a pseudo-homogeneous and an adsorption based, which accounts for the different affinities toward the polymeric matrix of all the species involved in the reaction and the solvent (triglycerides). For both the models, either the ideal or non-ideal behavior of the mixture was considered, and the results were compared. The kinetic parameters of the esterification of free fatty acid were regressed using a robust mathematical model and using equilibrated resins, i.e., all the experiments started only after having let the catalyst adsorb reactants and products at the operative conditions.

Performance of whole-cells lipase derived from Mucor circinelloides as a catalyst in the ethanolysis of non-edible vegetable oils under batch and continuous run conditions

The catalytic performance of whole Mucor circinelloides URM 4182 cells immobilized in polyurethane foam particles was assessed for the ethanolysis of different vegetable oils, including andiroba (Carapa guianensis), coconut (Cocos nucifera), jatropha (Jatropha curcas), macaw palm (Acronomia aculeata), and palm tree (Elaeis guineensis). In a typical batch run, the immobilized cells were added at a vegetable oil-to-ethanol molar ratio of 1:8 using tert-butanol as the solvent. Under these conditions, the biocatalyst showed consistent selectivity by producing the corresponding ester from each fatty acid. The highest yield was achieved in the ethanolysis of coconut (97%) and macaw palm (95%) oils whose fatty acid profiles showed predominant concentrations of lauric acid. These results suggested high specificity of intracellular lipases to convert saturated fatty acids into their respective ethyl esters. The ethanolysis activity of the immobilized cells was also assessed at different space times (60–80h) in a continuous packed-bed reactor using coconut oil as the feedstock. Better reactor performance was found at space time of 80h. In this condition, 92.7±1.5% of the fatty acids present in the coconut oil were converted into the corresponding ethyl esters. The average volumetric productivity was 3.5±0.7mgesterg−1biocatalysth−1 with no significant reduction in the reactor efficiency during 25 days.