Structural and Chemical Characterization of Hardwood from Tree Species with Applications as Bioenergy Feedstocks

Eucalypt species are a group of flowering trees widely used in pulp production for paper manufacture. For several decades, the wood pulp industry has focused research and development efforts on improving yields, growth rates and pulp quality through breeding and the genetic improvement of key tree species. Recently, this focus has shifted from the production of high quality pulps to the investigation of the use of eucalypts as feedstocks for biofuel production. Here the structure and chemical composition of the heartwood and sapwood of Eucalyptus dunnii, E. globulus, E. pillularis, E. urophylla, an E. urophylla-E. grandis cross, Corymbia citriodora ssp. variegata, and Acacia mangium were compared using nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD) and biochemical composition analysis. Some trends relating to these compositions were also identified by Fourier transform near infrared (FT-NIR) spectroscopy. These results will serve as a foundation for a more comprehensive database of wood properties that will help develop criteria for the selection of tree species for use as biorefinery feedstocks.

桉属树种是一类广泛应用于造纸制浆领域的开花乔木。数十年来，木材制浆产业始终将研发重心置于通过育种与关键树种的遗传改良，提升制浆产量、生长速率及纸浆品质。近年来，该产业的研究重心已从高品质纸浆生产，转向探索以桉树作为生物燃料生产原料的应用潜力。本研究采用核磁共振波谱法（nuclear magnetic resonance spectroscopy, NMR）、X射线衍射法（X-ray diffraction, XRD）以及生化成分分析，对比了邓恩桉（Eucalyptus dunnii）、蓝桉（E. globulus）、球枝桉（E. pillularis）、尾叶桉（E. urophylla）、尾叶桉×巨桉杂交种（E. urophylla-E. grandis cross）、柠檬杯果木斑叶亚种（Corymbia citriodora ssp. variegata）以及马占相思（Acacia mangium）的心材与边材的结构及化学组成；此外，研究还通过傅里叶变换近红外光谱（Fourier transform near infrared, FT-NIR）分析，识别出了与这些木材成分相关的部分变化规律。本研究结果将为构建更全面的木材特性数据库奠定基础，助力开发用于筛选生物炼制原料树种的评价标准。