Chemical and Environmental Engineering Department, University of California, Riverside, Riverside, CA 92507, USA.
Biotechnol Biofuels. 2011 Nov 15;4:52. doi: 10.1186/1754-6834-4-52.
Mixtures of prairie species (mixed prairie species; MPS) have been proposed to offer important advantages as a feedstock for sustainable production of fuels and chemicals. Therefore, understanding the performance in hydrothermal pretreatment and enzymatic hydrolysis of select species harvested from a mixed prairie is valuable in selecting these components for such applications. This study examined composition and sugar release from the most abundant components of a plot of MPS: a C3 grass (Poa pratensis), a C4 grass (Schizachyrium scoparium), and a legume (Lupinus perennis). Results from this study provide a platform to evaluate differences between grass and leguminous species, and the factors controlling their recalcitrance to pretreatment and enzymatic hydrolysis.
Significant differences were found between the grass and leguminous species, and between the individual anatomical components that influence the recalcitrance of MPS. We found that both grasses contained higher levels of sugars than did the legume, and also exhibited higher sugar yields as a percentage of the maximum possible from combined pretreatment and enzymatic hydrolysis. Furthermore, particle size, acid-insoluble residue (AcIR), and xylose removal were not found to have a direct significant effect on glucan digestibility for any of the species tested, whereas anatomical composition was a key factor in both grass and legume recalcitrance, with the stems consistently exhibiting higher recalcitrance than the other anatomical fractions.
The prairie species tested in this study responded well to hydrothermal pretreatment and enzymatic saccharification. Information from this study supports recommendations as to which plant types and species are more desirable for biological conversion in a mixture of prairie species, in addition to identifying fractions of the plants that would most benefit from genetic modification or targeted growth.
混合草原物种（混合草原物种；MPS）已被提议作为可持续生产燃料和化学品的原料具有重要优势。因此，了解从混合草原收获的选定物种在水热预处理和酶水解中的性能对于选择这些成分用于此类应用非常有价值。本研究考察了 MPS 中最丰富的成分的组成和糖释放：一种 C3 草（Poa pratensis），一种 C4 草（Schizachyrium scoparium）和一种豆科植物（Lupinus perennis）。本研究的结果为评估草和豆科物种之间的差异以及控制它们对预处理和酶水解的抗性的因素提供了一个平台。
在草和豆科物种之间以及影响 MPS 抗性的各个解剖成分之间发现了显著差异。我们发现两种草的糖含量均高于豆科植物，并且作为预处理和酶解联合产生的最大可能糖产量的百分比，也表现出更高的糖产量。此外，颗粒大小、酸不溶残留物（AcIR）和木糖去除率未发现对任何测试物种的葡聚糖消化率有直接显著影响，而解剖结构是草和豆科植物抗性的关键因素，茎始终比其他解剖部分表现出更高的抗性。
本研究中测试的草原物种对水热预处理和酶糖化反应反应良好。本研究提供的信息支持了有关在混合草原物种中哪些植物类型和物种更适合生物转化的建议，除了确定植物的哪些部分最需要遗传修饰或靶向生长。
