Pinus pinaster or Eucalyptus globulus wood samples were subjected to chemical processing (alkaline extraction or delignification-swelling treatments) under selected conditions and the solid residues produced used as substrates for the enzymic hydrolysis of their polysaccharide fractions. The sugar solutions obtained were supplemented with nutrients and used as fermentation media for lactic acid production with Lactobacillus delbrueckii NRRL B-445. The kinetics of the bioconversion stage were modelled, and the suitability of hydrolysates for fermentation purposes were discussed.