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

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 7680 U l(-1) and 8.2 g l(-1). Furthermore, the flow behaviour of fermentation broth was Newtonian and the maximum μ(ap) was 2.7×10(-3) Pa s. The MW of laccase was 64 kDa 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 1.8×10(6) Da, 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).