AbstractThe objective of this research was to study the changes in hardness and elastic modulus of wood cell walls treated with enzymes. Such changes greatly influence the properties of paper and wood composites. Two enzymes, hemicellulase and lipase, were selected for the treatment. Poplar samples (Populus euramevicana) were treated with hemicellulase, while samples of southern yellow pine (Pinus spp.) and Mongolia scotch pine (Pinus sylvestris L. var. mongolica Litv.) were treated with lipase. Mechanical properties of both treated samples were investigated by nanoindentation. The results showed some changes in the hardness and elastic modulus of the poplar cell wall treated by hemicellulase. Hardness and elastic modulus values of southern yellow pine and Mongolia scotch pine cell walls treated by lipase decreased with increasing amounts of the enzyme.