Evaluation of Biological Pretreatment of Rubberwood with White Rot Fungi for Enzymatic Hydrolysis

Abstract

e effects of biological pretreatment on the rubberwood (<i>Hevea brasiliensis</i>), was evaluated after cultivation of white rot fungi <i>Ceriporiopsis subvermispora</i>, <i>Trametes versicolor</i>, and a mixed culture of <i>C. subvermispora</i> and <i>T. versicolor</i>. The analysis of chemical compositions indicated that <i>C. subvermispora</i> had greater selectivity for lignin degradation with the highest lignin and hemicellulose loss at 45.06% and 42.08%, respectively, and lowest cellulose loss (9.50%) after 90 days among the tested samples. X-ray analysis showed that pretreated samples had a higher crystallinity than untreated samples. The sample pretreated by <i>C. subvermispora</i> presented the highest crystallinity of all the samples which might be caused by the selective degradation of amorphous components. Fourier transform infrared (FT-IR) spectroscopy demonstrated that the content of lignin and hemicellulose decreased during the biological pretreatment process. A study on hydrolysis of rubberwood treated with <i>C. subvermispora</i>, <i>T. versicolor</i>, and mixed culture for 90 days resulted in an increased sugar yield of about 27.67%, 16.23%, and 14.20%, respectively, as compared with untreated rubberwood (2.88%). The results obtained demonstrate that rubberwood is a potential raw material for industrial applications and white rot fungus <i>C. subevermispora</i> provides an effective method for improving the enzymatic hydrolysis of rubberwood.