Alternative heterologous expression of L-Arabinose Isomerase from Enterococcus faecium DBFIQ E36 by residual whey lactose induction

DE SOUZA, TICIANE C; CASEMIRO OLIVEIRA, RAVENA; DE SANTIAGO BEZERRA, SAULO G. ; MANZO, RICARDO M.; MAMMARELLA, ENRIQUE J.; HISSA, DENISE C.; ROCHA BARRO GONÇALVES, LUCIANA

MOLECULAR BIOTECHNOLOGY

HUMANA PRESS INC

Lugar: Oregon; Año: 2021

1073-6085

This study reports an alternative strategyfor the expression of a recombinant L-AI from Enterococcus faecium DBFIQ E36 by auto-induction using glucose andglycerol as carbon sources and residual whey lactose as inducer agent. Commerciallactose and isopropyl β-D-1-thiogalactopyranoside (IPTG) were also evaluated asinducers for comparison of enzyme expression levels. The enzymatic extracts werepurified by affinity chromatography, characterized and applied in the bioconversionof D-galactose into D-tagatose. L-AI presented a catalytic activity of 1.67 ±0.14 U.mL-1, 1.52 ± 0.01 U.mL-1 and 0.7 ± 0.04 U.mL-1,when expressed using commercial lactose, lactose from whey and IPTG,respectively. Higher activities could be obtained by changing the protocol ofenzyme extraction and, for instance, the enzymatic extract produced with wheypresented a catalytic activity of 3.8 U.mL-1. The specific activityof the enzyme extracts produced using lactose (commercial or residual whey)after enzyme purification was also higher when compared to the enzyme expressedwith IPTG. Best results were achieved when enzyme expression was conductedusing 4g.L-1 of residual whey lactose for 11h. Theseresults proved the efficacy of an alternative and economic protocol for theeffective expression of a recombinant L-AI aiming its high scale production.