To examine the utilization of cellulose and hemicellulose of corncob by M. thermophila, mature conidia were inoculated in 100 mL 1×VMM medium with 2% (w/v) corncob as carbon source. The cultures (25 mL) were harvested by filtering at different time-points and then washed with distilled water to obtain the total solids. For measuring the hemicellulose content, the solids were dried at 80 °C for 24 h, degraded in 1.5 mL 72% (w/w) H2SO4 at 30 °C for 1 h, after which 21.5 mL distilled water was added and the samples were incubated at 121 °C for 1 h. The final sample volume was adjusted to 25 mL. The xylose content in the acid hydrolysis samples was measured using high-performance liquid chromatography (HPLC) and used for calculating hemicellulose content. The xylose in the mycelia was ignored because it was present at low levels. Before measuring the cellulose content, 15 mL acid hydrolysis solution (acetic acid:nitric acid:H2O = 8:1:1) was added and the solution was vortexed and boiled for 1 h to eliminate mycelia and hemicellulose.
The solution was centrifuged and the precipitate was dried at 80 °C for 24 h. The dried samples were degraded as described above. The glucose content in the acid hydrolysis sample was measured for calculating cellulose content. The residual cellulose and hemicellulose contents (g/L) in the medium were calculated as follows: glucose content (g/L)/180.15 (g/mol) × (180.15 − 18.02) (g/mol); xylose content (g/L)/150.13 (g/mol) × (150.13 − 18.02) (g/mol).
The solution was centrifuged and the precipitate was dried at 80 °C for 24 h. The dried samples were degraded as described above. The glucose content in the acid hydrolysis sample was measured for calculating cellulose content. The residual cellulose and hemicellulose contents (g/L) in the medium were calculated as follows: glucose content (g/L)/180.15 (g/mol) × (180.15 − 18.02) (g/mol); xylose content (g/L)/150.13 (g/mol) × (150.13 − 18.02) (g/mol).
