Laccase functionalized cellulose acetate for the removal of toxic combustion products

Paper waste extracted α-cellulose fibers super-magnetized and chitosan-functionalized for covalent laccase immobilization

Enormous disposal of paper wastes (PW) causing number of environmental problems. PW is efficiently used to extract multifunctional α-cellulose fibers (αCFs). Thus, αCFs extraction from PW, and functionalization with Fe₃O₄ and chitosan were successfully performed for immobilization of laccase. Therefore, in this investigation, PW extracted αCFs were tuned with supermagnetic Fe₃O₄ (M) and functionalized with chitosan (CTA) (M-PW-αCF-CTA). Furthermore, M-PW-αCF-CTA was glutaraldehyde cross-linked for covalent laccase immobilization. The synthesized materials were characterized by FT-IR, TGA, FE-SEM, FE-HR-TEM and VSM analyzes. M-PW-αCF-CTA exhibited magnetic saturation value of 14.72 emu/g. Laccase immobilized on M-PW-αCF-CTA (M-PW-αCF-CTA-Lac) gave 92% of activity recovery and loading capacity of 73.30 mg/g. M-PW-αCF-CTA-Lac showed excellent pH, temperature, and storage stabilities with the exceptional reusability potential. Moreover, M-PW-αCF-CTA-Lac was applied for repeated removal of carcinogenic Direct Red 28 (DR28). Therefore, M-PW-αCF-CTA-Lac is green and economical biocatalyst with extraordinary separation potential can be enforced for environmental pollutants reclamation.

Preparation and Characterization of Cellulose Triacetate as Support for Lecitase Ultra Immobilization

The use of polymers as supports for enzyme immobilization is a strategy that enables to remove the enzymes from a chemical reaction and improve their efficiency in catalytic processes. In this work, cellulose triacetate (CTA) was used for physical adsorption of phospholipase Lecitase ultra (LU). CTA is more hydrophobic than cellulose, shows good performance in the lipases immobilization being a good candidate for immobilization of phospholipases. We investigated the immobilization of LU in CTA, the stability of the immobilized enzyme (CTA-LU) and the performance of CTA-LU using soybean oil as a substrate. LU was efficiently immobilized in CTA reaching 97.1% in 60 min of contact with an enzymatic activity of 975.8 U·g^-1. The CTA-LU system presents good thermal stability, being superior of the free enzyme and increase of the catalytic activity in the whole range of pH values. The difference observed for immobilized enzyme compared to free one occurs because of the interaction between the enzyme and the polymer, which stabilizes the enzyme. The CTA-LU system was used in the transesterification of soybean oil with methanol, with the production of fatty acid methyl esters. The results showed that CTA-LU is a promising system for enzymatic reactions.