After that, theflasks were closed with butyl rubber seals and aluminum caps andincubated for 72 h in a shaker incubator at 45◦C and 120 rpm. Liq-uid samples were periodically taken at various times during thehydrolysis, and the supernatant was separated from the residualsolid materials by centrifugation (3000 rpm for 15 min) and storedat −20◦C before sugar content analysis.