Effective and economically supported conversion of lignocellulosic biomass is not only related to high sugar yields but also to simple, environmentally friendly and sustainable technological solutions. Commercialization of the biofuel and biogas production technologies from lignocellulose is of high interest in many countries, however, costs and various yield affecting factors are still not fully understood. The aim of this research was to evaluate and define a mild-hydrolysis technique, involving the combination of simple physical, thermal and enzymatic methods. Use of medium-fine biomass (< 0.5 cm) wetted in purified (nanofiltrated) water, boiled to remove indigenous biomass microorganisms and enzymatically hydrolysed for 24 h at 30 °C was enough to obtain similar sugar yields than with sulphuric acid hydrolysis.