Laccase-based catalytic microreactor for BPA biotransformation

Abstract

A laccase-based catalytic reactor was developed into a polydimethylsiloxane (PDMS) microfluidic device, allowing the degradation of different concentrations of the emergent pollutant, Bisphenol-A (BPA), at a rate similar to free enzyme. Among the immobilizing agents used, 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) was capable of immobilizing a more significant amount of the laccase enzyme in comparison to glutaraldehyde (GA), and the passive method (2989, 1537, and 1905 U/mL, respectively). The immobilized enzyme inside the microfluidic device could degrade 55 ppm of BPA at a reaction rate of 0.5309 U/mL*min with a contaminant initial concentration of 100 ppm at room temperature. In conclusion, the design of a microfluidic device and the immobilization of the laccase enzyme successfully allowed a high capacity of BPA degradation.

Keywords: Biocatalytic reactor; Bisphenol a; Immobilization; Laccase; Microfluidic device.

Graphical abstract

Fig. 1

AutoCAD design for PMMA pre-recorded sheet. A - Sheet length 75 mm, B - Sheet width 25 mm, C - In and out diameters 2 mm, D - Horizontal trajectory 4 mm, E − Vertical trajectory 12 mm. The design has a total linear trajectory of 292 mm and a channel width of 1 mm.

Fig. 2

A) Standard curve obtained for the Bisphenol A quantification. B) Enzyme immobilization through the different cross-linking agents EDC, and GA contrasted with passive immobilization method (PA).

Fig. 3

ABTS oxidation in the biocatalytic reactor of enzymes immobilized with EDC.

Fig. 4

Final bisphenol A (BPA) transformation percentage at retention times of 1, 10, and 100 min with an initial concentration of A) 100 ppm., and B) 20 ppm. Bisphenol A (BPA) transformation at 1, 10, and 100 min retention times with an initial concentration of C) 100 ppm., and D) 20 ppm.