This study deals with pretreatment of wheat straw with lignin‐degrading fungi and its effect on chemical pulping. Ceriporiopsis subvermispora strains, which preferentially attack the lignin, were used for biochemical pulping of bagasse. Treatment of depithed bagasse with different strains of C. subvermispora reduced the κ number by 10–15% and increased unbleached pulp brightness by 1.1–2.0 ISO points on chemical pulping at the same alkali charge. Bleaching of biopulps at the same chemical charge increased final brightness by 4.7–5.6 ISO points and whiteness by 10.2–11.4 ISO points. Fungal treatment did not result in any adverse effect on the strength properties of pulp.