Production of lactobionic acid from lactose using the cellobiose dehydrogenase-3-HAA-laccase system from Pycnoporus...

The aim of this study was to produce lactobionic acid from lactose by a new Pycnoporus sp. SYBC-L10 strain. Recently, studies on enzymatic production of lactobionic acid mostly focus on cellobiose dehydrogenase from Sclerotium rolfsii CBS 191·62 and laccase from Trametes pubescens MB 89 oxidize lactose to lactobionic acid with redox mediators. In this study, we converted lactose to lactobionic acid by shaking flask fermentation without exogenous mediator in the reaction mixture. In this bioconversion process, lactose is efficiently converted into lactobionic acid with a specific productivity of up to 3·1 g l^-1  h^-1 and 96% yield. 3-Hydroxyanthranilic acid added externally to the reaction mixture can obviously accelerate the conversion of lactose to lactobionic acid. The results showed that 3-hydroxyanthranilic acid produced by the fungus itself is an important influencing factor in this bioconversion process. This study presents the first attempt to efficiently produce lactobionic acid by white-rot fungi, suggesting definite potential for Pycnoporus to produce lactobionic acid. SIGNIFICANCE AND IMPACT OF THE STUDY: Lactobionic acid has been applied to a wide range of applications in pharmaceutical, food, nanotechnology and chemical industries. Here, an attempt was done to produce lactobionic acid from lactose using the cellobiose dehydrogenase-3-HAA-laccase system in a fermentation system. After a survey of other methods to produce lactobionic acid by cellobiose dehydrogenase, this study explores a new and significant perspective for the production of lactobionic acid.