Acrylic fabric and nanomaterials to enhance α-amylase-based biocatalytic immobilized systems for industrial food applications

An innovative approach for immobilizing alpha-amylase was used in this investigation. The acrylic fabric was first treated with hexamethylene diamine (HMDA) and then coated with copper ions that were later reduced to copper nanoparticles (CuNPs). The corresponding materials obtained, Cu(II)@HMDA-TA and CuNPs@HMDA-TA, were employed as carriers for alpha-amylase, respectively. The structural and morphological characteristics of the produced support matrices before and after immobilization were assessed using various techniques, including FTIR, SEM, EDX, TG/DTG, DSC, and zeta potential. The immobilized alpha-amylase exhibited the highest level of activity at pH 7.0, with immobilization yields observed for CuNPs@HMDA-TA (81.7 %) (60 unit/g support) followed by Cu(II)@HMDA-TA (71.7 %) (49 unit/g support) and 75 % and 61 % of activity yields, and 91.7 % and 85 % of immobilization efficiency, respectively. Meanwhile, biochemical characterizations of the activity of the soluble and immobilized enzymes were carried out and compared. Optimal temperature, pH, kinetics, storage stability, and reusability parameters were optimized for immobilized enzyme activity. The optimal pH and temperature were recorded as 6.0 and 50 degrees C for soluble alpha-amylase while the two forms of immobilized alpha-amylase exhibit a broad pH of 6.0-7.0 and optimal temperature at 60 degrees C. After recycling 15 times, the immobilized alpha-amylase on CuNPs@HMDA-TA and Cu(II)@HMDA-TA preserved 63 % and 52 % of their activities, respec-tively. The two forms of immobilized alpha-amylase displayed high stability when stored for 6 weeks and preserved 85 % and 76 % of their activities, respectively. Km values were calculated as 1.22, 1.39, and 1.84 mg/mL for soluble, immobilized enzymes on CuNPs@HMDA-TA, and Cu(II)@HMDA-TA, and Vmax values were calculated as 36.25, 29.68, and 21.57 mu mol/mL/min, respectively. The total phenolic contents of maize kernels improved 1.4 +/- 0.01 fold after treatment by two immobilized alpha-amylases.

Automated summary

An innovative method for immobilizing alpha-amylase was developed by treating acrylic fabric with hexamethylene diamine (HMDA) and then coating it with copper ions that were reduced to copper nanoparticles (CuNPs). The immobilized alpha-amylase showed the highest activity at pH 7.0, with CuNPs@HMDA-TA exhibiting the highest immobilization yield of 81.7%. The immobilized enzymes also displayed high stability and retained a significant percentage of their activity after recycling and storage. The immobilized alpha-amylases also improved the total phenolic content of maize kernels by 1.4-fold.