Mechanistic analysis of thermal stability in a novel thermophilic polygalacturonase MlPG28B derived from the marine fungus Mucor lusitanicus

In this study, heterologous MlPG28B expression was obtained by cloning the Mucor lusitanicus gene screened from a marine environment. The enzyme activity of MlPG28B was maximum at 60 °C, 30 % of the enzyme activity was retained after incubation at 100 °C for 30 min, and enzyme activity was still present after 60 min incubation, one of the best thermostable polygalacturonases characterized until now. The high-purity oligosaccharide standards (DP2-DP7) were prepared with polygalacturonic acid as a substrate. Kinetic parameters showed that MlPG28B at the optimum temperature has a low K