Synthesis of hexyl butyrate (apple and citrus aroma) by Candida rugosa lipase immobilized on Diaion HP-20 using the Box-Behnken design.

This study aims at the synthesis of hexyl butyrate by Candida rugosa lipase (CRL) immobilized on Diaion HP 20. The lipase load used was 28.7 ± 2.1 mg/g (mg of lipase/g of support), whose hydrolytic activity was 132.0 ± 2.5 U/g. To obtain the maximum production of hexyl butyrate, the Box-Behnken design statistical planning was used, having as independent variables; biocatalyst concentration, temperature and acid:alcohol molar ratio and ester conversion as a dependent variable at 60, 180 and 480 min. For 60 min, 90.8% conversion was obtained at 47.25 ºC, 1:1.4 molar ratio and 17.65% of biocatalyst; 180 min, 94.5% conversion at 59.5 ºC, 1:2 molar ratio and 15.8% biocatalyst; 480 min, 95.01% conversion at 47.0 ºC, 1:2 molar ratio and 16.9% biocatalyst. CRL-Diaion HP 20 retained 60% of its initial activity after ten cycles of reactions showing potential for industrial use. The ester produced was identified by gas chromatography analyses. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01200-1.

Application of a constrained mixture design for lipase production by Penicillium roqueforti ATCC 10110 under solid-state fermentation and using agro-industrial wastes as substrate.

Solid state fermentation (SSF) simulates the natural conditions fungal growth, where the amount of water in the reaction medium must be restricted, thus limiting the use of liquid substrate. An analytical strategy to deal with this limitation is the design of blending with constraints. Thus, the objective of the work was to optimize two constrained waste mixtures for the production of lipase by Penicillium roqueforti ATCC 10110 under SSF, using different substrates that combine solid and liquid waste. For this, the best fermentation time was determined through a fermentative profile, afterwards a restricted-mix design with lower and upper limits of the components of mixture I (cocoa residue, solid palm oil residue and liquid palm oil residue) and II (cocoa residue, mango residue and palm oil residue liquid palm) was applied. By means of Pareto and contour graphs, the maximum production points of lipase in mixtures I (6.67 ± 0.34 U g-1) and II (6.87 ± 0.35 U g-1) were obtained. The restricted mixture design proved to be a promising tool in the production of lipase by P. roqueforti ATCC 10110 under SSF since the use of restrictions is useful when intending to combine solid and liquid residues in fermentation processes.

Candida rugosa lipase immobilized on hydrophobic support Accurel MP 1000 in the synthesis of emollient esters.

OBJECTIVES: To immobilize Candida rugosa lipase in Accurel MP 1000 (CRL-AMP) by physical adsorption in organic medium and apply in the synthesis of wax esters dodecanoyl octadecanoate 1 and hexadecanoyl octadecanoate 2 in a heptane medium, as well as evaluating the stability and recyclability of CRL-AMP in six reaction cycles. RESULTS: The specific activity (Asp) for CRL-AMP was 200 ± 20 U mg-1. Its catalytic activity was 1300 ± 100 U g-1. CRL-AMP was used in the synthesis of esters in heptane medium with a 1:1 acid:alcohol molar ratio at 45 °C and 200 rpm. In synthesis 1, conversion was 62.5 ± 3.9% in 30 min at 10% m v-1 and 56.9 ± 2.8% in 54 min at 5% m v-1; while in synthesis 2, conversion was 79.0 ± 3.9% in 24 min at 10% m v-1, and 46.0 ± 2.4% in 54 min at 5% m v-1. Reuse tests after six consecutive cycles of reaction showed that the biocatalyst retained approximately 50% of its original activity for both reaction systems. CONCLUSIONS: CRL-AMP showed a high potential in the production of wax esters, since it started from low enzymatic load and high specific activities and conversions were obtained, in addition to allowing an increase in stability and recyclability of the prepared biocatalyst.

High-throughput screening for distinguishing nitrilases from nitrile hydratases in Aspergillus and application of a Box-Behnken design for the optimization of nitrilase.

Nitrilases and nitrile hydratases/amidases hydrolyze nitriles into carboxylic acids and/or amides, which are used in industrial chemical processes. In the present study, 26 microorganisms, including yeasts and filamentous fungi, in a minimum solid mineral medium supplemented with glucose and phenylacetonitrile were screened to evaluate their biocatalytic potential. Of these microorganisms, five fungi of the genus Aspergillus were selected and subjected to colorimetry studies to evaluate the production and distinction of nitrilase and nitrile hydratase/amidase enzymes. Aspergillus parasiticus Speare 7967 and A. niger Tiegh. 8285 produced nitrilases and nitrile hydratase, respectively. Nitrilase optimization was performed using a Box-Behnken design (BBD) and fungus A. parasiticus Speare 7967 with phenylacetonitrile volume (µl), pH, and carbohydrate source (starch:glucose; g/g) as independent variables and nitrilase activity (U ml-1 ) as dependent variable. Maximum activity (2.97 × 10-3  U ml-1 ) was obtained at pH 5.5, 80 µl of phenylacetonitrile, and 15 g of glucose. A. parasiticus Speare 7967 showed promise in the biotransformation of nitriles to carboxylic acids.

Optimization of lipase production by Penicillium roqueforti ATCC 10110 through solid-state fermentation using agro-industrial residue based on a univariate analysis.

Lipases (triacylglycerol hydrolases, EC 3.1.1.3) are a class of enzymes with high industrial importance. An option for the production of this enzyme is through fungal growth via solid-state fermentation (SSF). Thus, this research presents a study of lipase production by Penicillium roqueforti ATCC 10110 through SSF using cocoa bran residues (Theobroma cacao) as a substrate. To achieve maximum lipase production, fermentation time (0 to 120 h) and palm oil (PO) percentage (0 to 50%) were optimized through analysis of one factor at a time (OFAT), with lipase activity as the response. The amount of cocoa was fixed (5 g), the incubation temperature was maintained at 27 °C, and the moisture content was established at 70%. For a 72 h incubation, the highest enzyme activity achieved using SSF without adding PO was 14.67 ± 1.47 U g-1, whereas with PO (30%), it was 33.33 ± 3.33 U g-1, thus demonstrating a 44% increase in enzyme activity. Through the OFAT methodology, it was possible to confirm that supplementation with palm residue was efficient and maximized the lipase of P. roqueforti ATCC 10110.

Development of procedure for sample preparation of cashew nuts using mixture design and evaluation of nutrient profiles by Kohonen neural network.

A procedure using ICP OES for sample preparation for the determination of copper, iron and manganese in cashew nuts was developed. Constrained simplex-centroid design was applied in the optimization of the digestion in microwave oven procedure, and the results evaluated from topological maps of the Kohonen network. The best proportion evaluated for the digestion of the sample with HNO3, H2O2 and H2O was 10:45:45 (%). With optimized conditions, the detection limits were 0.63, 4.3 and 0.37 mg kg-1, and quantification 2.1, 14 and 1.2 mg kg-1 for Cu, Fe and Mg, respectively. The precision (% RSD) was 1.84, 2.31 and 2.73, for Cu, Fe and Mg, respectively. The procedure proposed had the accuracy confirmed using NIST 1568b (at 95% reliability) and was applied in the samples obtaining concentrations in the range of 10.7-19.4, 44.3-67.2 and 11.0-21.4 mg kg-1 for Cu, Fe and Mg, respectively.