Potential of the new endophytic fungus Hormonema sp CECT-13092 for improving processes in lignocellulosic biorefineries: biofuel production and cellulosic pulp manufacture

BACKGROUND: The utility of the ascomycete Hormonema sp. CECT-13092, an endophytic fungal strain recently isolated and identified from an eucalyptus tree in Spain, was investigated in different biorefineries-industrial processes. The strain was used to improve the enzymatic saccharification and pulping of Eucalyptus globulus wood; and liquid culture of the strain enriched in laccase activity was used for E. globulus Kraft pulp biobleaching in the presence of acetosyringone as mediator. RESULTS: With regard to enzymatic saccharification, treatment with Hormonema sp. and autohydrolysis pretreatment boosted enzymatic hydrolysis (eight-fold increase in sugar yields compared with control without any pretreatment). This fungus provided 26.7% higher delignification than the control during Kraft pulping and a higher refining degree during mechanical pulping (69 degrees SR vs. 48 degrees SR control). Chemical and mechanical pulps from fungal pretreatment also showed better physical properties than control pulps (increases in tensile, tear and burst indexes of 28.4%, 15.6% and 43.9%, respectively). Regarding biobleaching, after the enzymatic treatment and a hydrogen peroxide stage, a brightness increase (2.3 points %ISO) was obtained. CONCLUSIONS: The potential of the endophytic fungal strain Hormonema sp. for biotechnological applications such as fermentable sugars production, biopulping and biobleaching has been demonstrated. In this sense, this is the first study on the use of an endophytic fungus for a biobleaching sequence. (C) 2016 Society of Chemical Industry