BACKGROUND The objective of this research was to compare the efficiency of pepsin immobilization by adsorption and covalent binding on biochar obtained from pupunha palm processing residue, and to use the immobilized enzyme in the hydrolysis of bovine casein. RESULTS The surface modification of biochar with glutaraldehyde was effective, as shown by Fourier transform infrared analyses and the texture properties of the carbons. Both activated and functionalized biochar showed high immobilization efficiency (>95%) and high enzyme‐support binding capacity (>96 mg g–1). During the activity assays, the functionalized carbon showed a higher casein hydrolysis rate when compared to the enzyme immobilized by adsorption, with values of 39.17 U and 32.67 U, respectively, and c. 95% of the activity of the free enzyme, after 60 min. CONCLUSION The functionalization of the biochar led to a surface modification of biochar by the insertion of amine‐aldehyde groups, which was responsible for the formation of strong interactions between the support material and the enzyme, thus providing a greater proteolytic activity when compared to immobilization by adsorption. The immobilized enzymes were able to maintain their proteolytic activity for more than seven cycles of reuse. © 2019 Society of Chemical Industry

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Agro‐industrial wastes are used as carbon precursors in the production of activated carbon because they are rich in lignocellulosic materials. This study aimed to investigate the relationship between the main characteristics of precursor materials and activated carbons by multivariate analysis. After characterization of the precursor materials and their respective carbons, the principal component analysis and canonical correlation analysis were performed. Materials with cellulose/lignin ratio > 3.0 led to the production of carbons with a higher pore diameter, while materials with a cellulose/lignin ratio ≤ 1.0 led to a low pore volume. Using the mathematical models obtained, it is possible to predict the carbon characteristics using only the composition data of the lignocellulosic materials.

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BACKGROUND: Biotechnology has revolutionized the use of enzymes for application in industrial processes. The present work evaluated the effect of functionalizing activated carbon with metallic nanoparticles obtained from corn cob residue on lipase immobilization. The aim was to improve the enzymatic activity of the immobilized enzyme and subsequent application of derivatives in the synthesis of isoamyl acetate ester (banana flavor). RESULTS:The activated carbon (CCAC) had a mesoporous structure and specific surface area of 1135 m 2 g −1 , characteristic of supports from precursor material with a high cellulose content, which was reduced in metalized carbon (CCACM) due to the insertion of metallic particles (760 m 2 g −1 ). CCACM showed a slightly higher lipase absorptive capacity than CCAC (280.72 ± 0.27 mg g −1 and 276.46 ± 0.03 mg g −1 , respectively). Furthermore, for derivatives the optimal reaction medium conditions were pH 7.0 and 30 °C, confirming the advantage associated with lipase immobilization, obtaining activity values of 84.0 ± 2.12 U, 72.3 ± 1.7 U and 31.4 ± 1.9 U, for lipase immobilized on CCACM, CCAC and native form, respectively. The derivatives showed potential application in the synthesis of isoamyl acetate ester, with conversions above 90% and stability during five cycles of use. CONCLUSION:The activated carbon metallization process showed an increase in lipase immobilization efficiency and proved to be a promising support, since there was an increase in its enzymatic activity and the derivatives obtained showed potential application in aroma synthesis, reaching conversion above 90%.