50 / 2019-12-07 12:50:54

Py-GC-MS analysis of fungal pretreated corn stover

fungal pretreatment；pyrolysis-gas chromatography mass spectrometry；delignification

To obtain a more detailed insight into the chemical modifications of the lignin structure after fungal pretreatment, the untreated and treated corn stovers were analyzed by pyrolysis-gas chromatography mass spectrometry (Py-GC/MS) [1, 2]. Fig1 shows the pyrograms of the untreated and fungal treated samples, which were dominated by peaks of phenolic compounds derived from the lignin moiety[3]. The identities and relative abundances of the lignin-derived compounds released are listed in Table 1. After fungal pretreatment, the total abundance of lignin-derived compounds decreased by 54.0 %, which means that fungal treatment led to a considerable degradation of lignin. In addition, the total peak area of H-, G- and S-type lignin derivatives was reduced by 44.0 %, 52.5 % and 60.1 % respectively, indicating that fungus preferentially degrades S-type units, followed by G-type units, and is least efficient at degrading H-type units. Compared with the raw sample, the treated sample contained less S-type lignin derivatives, which means that fungal delignification could have led to a substantial demethoxylation of lignin, and part of the G and H units in the treated sample might be derived from the fungal demethoxylation of S units [4]. The basic analysis of lignin structure using Py-GC/MS revealed that the selective white-rot fungus possesses strong demethoxylation properties and is a powerful tool for delignification. It may provide an efficient system for exploring new and effective delignification strategies.