Lactobionic acid production via mutant cellobiose dehydrogenase/laccase continuous enzymatic regeneration of electron acceptors

Abstract

Lactobionic acid (LBA) has diverse number of applications in pharmaceutical, food, chemical and nanotechnology fields. Bioproduction of LBA by bi-enzymatic cellobiose dehydrogenase (CDH)/laccase (LAC) is a system where CDH catalyses oxidation of lactose to LBA, whilst LAC has, at the same time, ability to regenerate the redox mediator as electron acceptor for CDH. In this study, CDH mutants derived from Phanerochaete chrysosporium produced in Pichia pastoris were used to determine LBA production rate with varying number of redox mediators. The highest specific productivity was observed for triple mutant CDH (tmCDH) for all redox mediators used in this study. The notable redox mediator was hydroquinone where specific productivity was 29.14 g L−1 kU−1 for tmCDH while specific productivity with DCIP was 27.2 g L−1 kU−1, with ABTS showed 19.1 g L−1 kU−1.