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The use of new materials in the field of biofuel production has been represented as a step in the development of remarkable catalysts. The use of lipases in the production of biodiesel is often seen as a cost-limiting step, as the operating expenses in recovering such catalysts can lead to unfeasible market expectations. In this study, hydroxyapatite (HAp) particles were evaluated as a support to immobilize commercial lipase, following application in ethyl ester synthesis. First, hydroxyapatite was synthesized through the co-precipitation method at constant pH and selected as a support to be used in enzyme immobilization. The characterization of the biocatalyst support materials produced was carried out using DRX, BET, FTIR, TGA, and SEM analysis. The lipase from Thermomyces lanuginosus was then immobilized in the matrices, and, subsequently, there was transesterification of the vegetable oil deodorization distillate (VODD). The biodiesel samples generated showed that they were within commercial standards, achieving ester conversion greater than 96.5%. Other properties such as density (0.87 g.cm−3) and viscosity (4.36 mm2.s−1) meet the specifications required by ASTM to be used as a biofuel. In the experiment planning technique, the results revealed an experimental trend and a defined behavior: a higher lipase loading in the immobilization and the use of temperatures in the range of 40–50 °C favor high conversions of ethyl esters. Thus, this confirms that the enzymatic chemical catalyst was able to form the main fatty acid esters even using a residual lipid raw material. [ABSTRACT FROM AUTHOR]

This study deals with lipase immobilization on micro- and mesoporous silica-based materials. The effects of the type of support (silica MCM-41, zeolite HZSM-5 (SAR 25), zeolite HZSM-5 (SAR 280), and the silica-aluminas Siral 10, Siral 20, and Siral 40) were investigated on the immobilization of lipase B from Candida antarctica (CALB) and lipase from Rhizomucor miehei (RML). The supports that allowed the highest immobilization efficiencies for the CALB were Siral 40 (91.4%), HZSM-5 (SAR 280) (90.6%), and MCM-41 (89.4%). Siral 20 allowed the highest immobilization efficiency for RML (97.6%), followed by HZSM-5 (SAR 25) (77.1%) and HZSM-5 (SAR 280) (62.7%). The effect of protein concentration on lipase immobilization was investigated, and the results adjusted well on the Langmuir isotherm model (R2 > 0.9). The maximum protein adsorption capacity of the support determined by the Langmuir model was equal to 10.64 and 20.97 mgprotein gsupport−1 for CALB and RML, respectively. The effects of pH (pH 7.0 and pH 11.0) and phosphate buffer solution concentration (5 and 100 mmol L−1) were also investigated on lipase immobilization. The immobilization efficiency for both lipases was similar for the different pH values. The use of 100 mmol L−1 phosphate buffer decreased the lipase immobilization efficiency. The biocatalysts (CALB-Siral 40 and RML-Siral 20) were tested in the ethyl oleate synthesis. The conversion of 61.7% was obtained at 60 °C in the reaction catalyzed by CALB-Siral 40. Both heterogeneous biocatalysts showed increased thermal stability compared with their free form. Finally, the reuse of the biocatalysts was studied. CALB-Siral 40 and RML-Siral 20 maintained about 30% of the initial conversion after 3 batches of ethyl oleate synthesis. Silica-aluminas (Siral 20 and 40) proved to be a support that allowed a high efficiency of immobilization of lipases and activity for esterification reaction. [ABSTRACT FROM AUTHOR]

High internal phase emulsions (HIPEs) can be applied as templates for synthesis of porous polymers, which can be used in several industrial areas as catalyst supports and column fillers. For this reason, the present work evaluated the use of HIPEs for synthesis of porous poly(styrene‐co‐divinylbenzene) (P[S‐co‐DVB]) particles through suspension polymerizations. Firstly, the effects of HIPE preparation conditions (surfactant concentration, stirring speed and the duration of the stirring step) on the properties of the obtained particles are investigated. As observed experimentally, the increase of the stirring speed, of the duration of the stirring step and of the surfactant concentration led to reduction of primary cavity dimensions and to higher number of interconnecting pores. Then, the effects of reaction parameters (DVB content, presence of a porogenic agent and the holdup of the organic phase) on the properties of obtained particles are also evaluated. It is observed that the addition of heptane as porogenic agent and the increase of the organic holdup led to increase of the specific area and porosity of the produced spherical polyHIPEs beads, which can exhibit specific area of 33 m².g−1, specific volume of pores of 0.25 cm³.g−1 and large pore diameters (ranging from 100–1100 Å). Thus, it is shown that the proposed technique can be used for manufacturing of new supports for enzyme immobilization. [ABSTRACT FROM AUTHOR]

Many studies describe the advantages of using hydrophobic particles on lipase immobilisation. However, many of these works neglect the effect of other variables of the supports, such as specific area and porosity, on the biocatalyst performance, and do not evaluate the influence of the hydrophobicity level of the particles on the biocatalysts' activity as a single variable. Thus, the focus of the present work was to evaluate the effect of the hydrophobicity degree of polymeric particles on the biocatalysts' activities, mitigating the influence of other variables. The study was divided into two steps. Firstly, distinct particles, exhibiting different composition and hydrophobicity levels, were used for the immobilization of a commercial lipase B from Candida antarctica (CAL-B). Then, distinct core-shell polymeric particles presenting different functional compounds on the surface were produced, using as comonomers styrene, divinylbenzene, 1-octene, vinylbenzoate and cardanol. Such particles were subsequently used for CAL-B immobilisation and the performance of the biocatalysts was evaluated on hydrolysis (using p-nitrophenyl laurate, as substrate) and esterification (using ethanol and oleic acid, as substrate) reactions. Based on the screening step, it was observed that for non-porous particles the correlation coefficients between the hydrophobicity level of the supports and the biocatalysts performance, for both hydrolysis and esterification reactions, were very low (0.32 and 0.45, respectively). It highlights that there was no significant correlation between these variables and that, probably, the chemical composition of the polymeric chains affects more significantly the biocatalyst performance. Then, analysing the subsequent stage, it was observed that small changes in the surface composition of the core-shell particles result in significant changes on the textural properties of the supports (specific area ranging from 1.2 m2.g−1 to 18.3 m2.g−1; and contact angles ranging from 71° (hydrophilic particles) to 92° (hydrophobic supports) when polymer films were put in contact with water). Such particles were also employed on CAL-B immobilization and it was noticed that higher correlation coefficients were achieved for hydrolysis (ρ = 0.53) and esterification (ρ = 0.74) reactions. Therefore, it is shown that the hydrophobicity degree of such supports starts to affect more effectively the biocatalysts performance when other textural features of the supports become more significant, such as specific area and porosity. [ABSTRACT FROM AUTHOR]

New nanoparticles are synthesized through emulsion polymerization, using distinct comonomers (styrene, divinylbenzene, glycidyl methacrylate and pentafluorostyrene). Then, for the first time, two strategies are adopted to functionalize such nanoparticles using benzylamine and thiophenol: (i) after the manufacture of the nanoparticles; and (ii) in situ during the polymerization reaction. Afterwards, the functionalized nanoparticles are used as nanosupports for immobilization of lipase B from Candida antarctica and the performance of the novel nanobiocatalysts are evaluated. It is shown that the nanoparticles exhibit different properties (specific areas ranging from 34 m2 g−1 to 324 m2 g−1; and contact angles ranging from 29° to 126°), indicating that both procedures can be used to adjust the properties of the polymer supports. Moreover, the nanobiocatalysts are applied successfully in hydrolysis and esterification reactions, exhibiting higher activities than the non‐functionalized biocatalysts. It is also observed that more hydrophilic supports result in more active biocatalysts in hydrolysis (27 ± 1 U g−1) and intermediate hydrophobic matrices conduct to more active biocatalysts in esterification reactions (1564 ± 50 U g−1). It is shown that highly hydrophobic surfaces may cause a significant decrease in the activity of such biocatalysts, probably due to distortions on the enzyme active center and to more intense chemical partitioning effects. [ABSTRACT FROM AUTHOR]

BACKGROUND This study investigated the use of core–shell biocatalysts, synthesized using recombinant lipase B from Candida antarctica (CALB), for the production of isopropyl palmitate and the optimization of this biocatalytic route. RESULTS: Initially, three distinct core–shell biocatalysts, were evaluated for the production of isopropyl palmitate and the CALB‐P(S‐co‐DVB)/P(S‐co‐DVB) biocatalyst (biocatalyst made of polystyrene‐co‐divinylbenzene core–shell particles) was the most suitable biocatalyst for this purpose. The effect of organic solvents – n‐hexane, isooctane, n‐heptane and cyclohexane – in the ester conversion was evaluated, and the most suitable solvent was the isooctane. The optimal reaction conditions were pursued conducting an optimization statistical analysis. The most suitable reaction conditions were identified: reaction temperature, 55°C; substrate molar ratio, 1:1.42 (palmitic acid: isopropyl alcohol); biocatalyst content, 24% w/w. Finally, the reuse of the biocatalyst was evaluated and the relative enzymatic activity remained up to 50% after the fourth cycle. CONCLUSION: Results were compared with commercial biocatalyst and the home‐made enzymatic biocatalyst (CALB‐P(S‐co‐DVB/PS‐co‐DVB) showed promise for application in the synthesis of isopropyl palmitate. The optimization study improved reaction conversion from 30% to 78%. The home‐made biocatalysts exhibited better performance for the synthesis of isopropyl palmitate compared with the commercial Novozym 435, using the same enzymatic activity. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The oleaginous yeast Moniliella spathulata R25L270 was the first yeast able to grow and produce extracellular lipase using Macaúba (Acrocomia aculeate) cake as substrate. The novel lipase was recently identified, and presented promising features for biotechnological applications. The M. spathulata R25L270 lipase efficiently hydrolyzed vegetable and animal oils, and showed selectivity for generating cis-5,8,11,15,17-eicosapentaenoic acid from sardine oil. The enzyme can act in a wide range of temperatures (25-48 °C) and pH (6.5-8.4). The present study deals with the immobilization of M. spathulata R25L270 lipase on hydrophobic, covalent and ionic supports to select the most active biocatalyst capable to obtain omega-3 fatty acids (PUFA) from sardine oil. Nine immobilized agarose derivatives were prepared and biochemically characterized for thermostability, pH stability and catalytic properties (KM and Vmax). Ionic supports improved the enzyme-substrate affinity; however, it was not an effective strategy to increase the M. spathulata R25L270 lipase stability against pH and temperature. Covalent support resulted in a biocatalyst with decreased activity, but high thermostability. The enzyme was most stabilized when immobilized on hydrophobic supports, especially Octyl-Sepharose. Compared with the free enzyme, the half-life of the Octyl-Sepharose derivative at 60 °C increased 10-fold, and lipase stability under acidic conditions was achieved. The Octyl-Sepharose derivative was selected to obtain omega-3 fatty acids from sardine oil, and the maximal enzyme selectivity was achieved at pH 5.0. [ABSTRACT FROM AUTHOR]