Loblolly pine residue prepared with and without zeolite ZSM-5 was pyrolyzed at 600℃ and the pyrolysis oil was hydrogenated using formic acid as a hydrogen source, in the presence of a Ru/activated carbon catalyst. As indicated by the pyrolysis yield, addition of the zeolite ZSM-5 increased the yield of light oil but decreased the yield of heavy oil. The pyrolysis oils were analyzed by ¹³C-, ³¹P-, ¹⁹F-nuclear magnetic resonance (NMR), and heteronuclear single quantum coherence or heteronuclear single quantum correlation nuclear magnetic resonance (HSQC-NMR), demonstrating that the zeolite ZSM-5 can efficiently induce decarboxylation reactions and decrease the content of aliphatic hydroxyl groups in the heavy oil by 57%. After hydrogenation of the pyrolysis oil, the aromatic carbon content decreased by 78%, with a significant increase in the aliphatic carbon content.

In this study, cellulose and xylan were in vitro fermented by pig fecal bacteria. Rapid fermentation (40 h) and extended fermentation (eight weeks) were performed. The properties and ultra-structure changes of post-fermented solid residues were studied. In the end effluent, acetic acid, propionic acid, and butyric acid were observed to be the principal short-chain fatty acids (SCFAs) produced by anaerobic fermentation. Xylan was more accessible to bacteria than cellulose, leading to higher SCFA and lactic acid production. In addition, the crystalline structure of cellulose changed, leading to 16.3% and 42.1% increases in crystallinity index for rapid and extended fermentation, respectively. Through this research, a systematic and advanced method to study the degradation chemistry of cellulose and xylan during fermentation was developed.