High-level coproduction, purification and characterisation of laccase and exopolysaccharides by Coriolus versicolor

•A two-stage pH-shift strategy was developed for coproduction of laccase and EPS.•Highest laccase and EPS production can reach 7680Ul−1 and 8.2gl−1, respectively.•Higher substrate conversion to metabolites rather than to biomass was obtained.•The MW and pI of laccase is 64kDa and 4.2, and it has α-helical content of 68%.•The protein-bound EPS (MW: 1.8×106Da) mainly consists of galactose, mannose and xylose. In this study, a two-stage pH-shift fermentation process was developed for the coproduction of laccase and exopolysaccharides (EPS) by Coriolus versicolor. At the same time, laccase and EPS were purified and characterised in detail. The results showed that the highest laccase and EPS production reached 7680Ul−1 and 8.2gl−1. Furthermore, the flow behaviour of fermentation broth was Newtonian and the maximum μap was 2.7×10−3Pas. The MW of laccase was 64kDa and it showed a pI value of 4.2. The CD analysis showed that laccase had a high α-helical content (68%). The MW of the purified EPS was determined to be 1.8×106Da, consisting of carbohydrates (87.6%) and proteins (12.4%). The EPS consisted of 17 amino acids, mainly serine (11.3%), glutamic acid (12.60%), leucine (13.3%) and phenylalanine (9.4%) in protein moiety, and three monosaccharides (galactose, mannose and xylose).