-Superparamagnetic nanomaterials have attracted interest in many areas due to the high saturation magnetization and surface area. For enzyme immobilization, these properties favor the enzyme-support contact during the immobilization reaction and easy separation from the reaction mixture by use of low-cost magnetic processes. Iron oxide magnetic nanoparticles (Fe3O4, MNPs), produced by the co-precipitation method, functionalized with 3-aminopropyltriethoxysilane (APTES) and glutaraldehyde (GLU), were evaluated as a solid support for Candida antarctica lipase B (CALB) immobilization. The nanomagnetic derivative (11nm) obtained after CALB immobilization (MNPs/APTES/GLU/CALB) was evaluated as biocatalyst in isoniazide (INH) synthesis using ethyl isonicotinate (INE) and hydrazine hydrate (HID) as substrates, in 1,4-dioxane. The results showed that MNPs/APTES/CALB had a similar performance when compared to a commercial enzyme Novozym 435, showing significant advantages over other biocatalysts, such as Rhizhomucor miehei lipase (RML) and CALB immobilized on non-conventional, low-cost, chitosan-based supports.

BACKGROUND Novel magnetite‐lignin hybrid materials were synthesized using lignin from cashew apple bagasse (CAB) and iron oxide nanoparticles (magnetite, Fe3O4). The new material, termed MNs/Lig (magnetite conjugated with lignin), was used as a support for the immobilization of lipase B from Candida antarctica (CAL─B), aiming to obtain an active and stable biocatalyst that is easily recoverable from the reactional medium. RESULTS The magnetite/lignin composite showed a higher thermal stability than pure lignin, and it presented good magnetic properties, both before and after the immobilization procedure. The immobilization yield was higher using the unaltered MN/Lig as a support than when using the glutaraldehyde‐activated MNs/Lig (MNs/Lig_GA), with yields of 66.6% and 40.0%, respectively. The presence of Triton X‐100 did not influence the immobilization yield or the thermal stability of the biocatalyst when employing the unaltered MNs/Lig. However, it influenced the thermal stability of the lipase immobilized on MNs/Lig_GA, lowering the biocatalyst stability, which showed a half‐life 11‐fold lower than that of MNs/Lig_GA_CALB. The biocatalysts were tested with regards to the synthesis of ethyl oleate using oleic acid and ethanol as substrates, and 2‐ethylhexyl oleate (a biolubricant) using oleic acid and 2‐ethyl‐hexanol as substrate. The conversions obtained by MNs/Lig_Tri_CALB were 88.2% and 76.7% for ethyl oleate and 2‐ethylhexyl oleate, respectively. CONCLUSION The novel strategy presented in this work for obtaining a biocatalyst using synthesized hybrids (MNs/Lig) may be a promising route for lipase immobilization because it can be considered environmentally benign and it shows a strong potential use in several reactions of industrial interest. © 2021 Society of Chemical Industry (SCI).

The lignins resulting of pretreatment from cashew apple bagasse with alkaline hydrogen peroxide and acid/alkali were extracted and characterized. The extracted lignin's showed similar characteristics to those mentioned in the literature, becoming a product of great potential raw for production of different materials. The application of the obtained lignins as material shows a positive impact for the economy.

RESUMO -A Isoniazida (INH) ou hidrazida do ácido 4-piridinocarboxílico é um destacado fármaco usado no tratamento da tuberculose. INH é preparado, convencionalmente, partindo da hidrólise da 4-cianopiridina, processo que ocorre com grande dispêndio energético e conduzida com uso de substâncias nocivas como é o caso da 4-cianopiridina, que além de nociva é preparada a partir da 4-picolina, que tem um elevado custo. Recentemente, estudos mostraram que a INH pode ser produzida em processos catalisados por lipases, conduzidos em condições amenas. Neste trabalho, apresentamos a aplicação de lipase do tipo B de Candida antarctica (CALB) imobilizada em sistemas biocatalíticos magnéticos nanoparticulados (CALB-NPM) para a produção de INH. Conversões próximas à 18,0% e atividade de hidrazinólise igual à 0,16±0,03 Mol/mg.mL.h foram atingidas neste trabalho e apresentam-se como resultados promissores apontando para a viabilidade do uso de CALB-NPM como biocatalisador na produção de INH.