Evaluation of biological pretreatment with white rot fungi for the enzymatic hydrolysis of bamboo culms

Abstract

Biological pretreatment with white rot fungi has shown potential for improving enzymatic hydrolysis of wood and grass. In this study, 34 isolates of white rot fungi were screened for the biological pretreatment of bamboo culms (Phyllostachys pubescence). Echinodontium taxodii 2538 and Trametes versicolor G20 were selected for further evaluation of pretreatment because they caused high lignin loss (>20%) and high selectivity value of lignin degradation (>2) after the 4-week biodegradation. Fermentable sugar yield of bamboo culms pretreated with these two fungi through enzymatic hydrolysis increased with increasing pretreatment time. Sugar yield of bamboo culms pretreated with T. versicolor G20 and E. taxodii 2538 increased 5.15-fold and 8.76-fold, respectively, after 120-day pretreatment. FTIR analysis showed that E. taxodii 2538 preferentially degraded the lignin of bamboo culms. The pretreated bamboo culms showed significant increase of initial adsorption capacity to cellulase (4.20-fold and 6.66-fold for T. versicolor G20 and E. taxodii 2538, respectively, after 120 days) and decrease of lignin content (12.00% and 29.14% for T. versicolor G20 and E. taxodii 2538, respectively, after 120 days) with increasing pretreatment time. Initial adsorption capacity and lignin content of bamboo culms were correlated to fermentable sugar yield. Scientific relevance This paper focused on the biodegradation and pretreatment of bamboo culms with white rot fungi. Bamboo culms pretreatment with white rot fungi was evaluated firstly for energy convention of lignocellulose. This paper studied effects of lignin content and initial adsorption capacity on enzymatic hydrolysis also.