Kadam Kiran L, Chin Chim Y, Brown Lawrence W
PureVision Technology, Inc., 511 McKinley St., Ft Lupton, CO, 80621, USA.
J Ind Microbiol Biotechnol. 2008 May;35(5):331. doi: 10.1007/s10295-008-0322-0. Epub 2008 Feb 14.
A new biorefining process is presented that embodies green processing and sustainable development. In the spirit of a true biorefinery, the objective is to convert agricultural residues and other biomass feedstocks into value-added products such as fuel ethanol, dissolving pulp, and lignin for resin production. The continuous biomass fractionation process yields a liquid stream rich in hemicellulosic sugars, a lignin-rich liquid stream, and a solid cellulose stream. This paper generally discusses potential applications of the three streams and specifically provides results on the evaluation of the cellulose stream from corn stover as a source of fermentation sugars and specialty pulp. Enzymatic hydrolysis of this relatively pure cellulose stream requires significantly lower enzyme loadings because of minimal enzyme deactivation from nonspecific binding to lignin. A correlation was shown to exist between lignin removal efficiency and enzymatic digestibility. The cellulose produced was also demonstrated to be a suitable replacement for hardwood pulp, especially in the top ply of a linerboard. Also, the relatively pure nature of the cellulose renders it suitable as raw material for making dissolving pulp. This pulping approach has significantly smaller environmental footprint compared to the industry-standard kraft process because no sulfur- or chlorine-containing compounds are used. Although this option needs some minimal post-processing, it produces a higher value commodity than ethanol and, unlike ethanol, does not need extensive processing such as hydrolysis or fermentation. Potential use of low-molecular weight lignin as a raw material for wood adhesive production is discussed as well as its use as cement and feed binder. As a baseline application the hemicellulosic sugars captured in the hydrolyzate liquor can be used to produce ethanol, but potential utilization of xylose for xylitol fermentation is also feasible. Markets and values of these applications are juxtaposed with market penetration and saturation.
本文介绍了一种体现绿色加工和可持续发展的新型生物精炼工艺。本着真正生物精炼厂的精神，其目标是将农业残留物和其他生物质原料转化为增值产品，如燃料乙醇、溶解浆和用于树脂生产的木质素。连续生物质分馏工艺可产生富含半纤维素糖的液流、富含木质素的液流和固体纤维素流。本文总体讨论了这三种物流的潜在应用，并特别给出了以玉米秸秆纤维素流作为发酵糖源和特种纸浆的评估结果。由于与木质素的非特异性结合导致的酶失活最小，这种相对纯净的纤维素流的酶水解所需的酶负载量显著降低。结果表明木质素去除效率与酶消化率之间存在相关性。所生产的纤维素还被证明是硬木浆的合适替代品，特别是在挂面纸板的顶层。此外，纤维素相对纯净的性质使其适合作为制造溶解浆的原料。与行业标准的硫酸盐制浆工艺相比，这种制浆方法的环境足迹显著更小，因为不使用含硫或含氯化合物。虽然这种方法需要一些最少的后处理，但它生产的商品价值高于乙醇，而且与乙醇不同，它不需要水解或发酵等广泛的加工过程。本文还讨论了低分子量木质素作为木材胶粘剂生产原料的潜在用途及其作为水泥和饲料粘合剂的用途。作为基准应用，水解液中捕获的半纤维素糖可用于生产乙醇，但木糖用于木糖醇发酵的潜在利用也是可行的。这些应用的市场和价值与市场渗透率和饱和度并列呈现。
