Direct, high-yield conversion of cellulose into biofuel
Direct, high-yield conversion of cellulose into biofuel
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DOI：
10.1002/anie.200801594
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发表时间：
2008-01-01
影响因子：
16.6
通讯作者：
Nikitin, Edward B.
中科院分区：
文献类型：
--
作者：
Mascal, Mark;Nikitin, Edward B.
这是在生物能源研究领域的巨大激励的日子。当然，其中的利害关系是经济独立于政治不稳定的石油出口国，纠正大气中的温室气体水平及其对气候的潜在影响，以及减轻我们即将达到石油峰值点的经济后果，特别是考虑到亚洲新兴经济超级大国的工业化步伐。可以说，全球能源问题的最终答案将最有可能在于基于氢和太阳能的超清洁技术。[1]然而，很少有人会否认碳基燃料的更近的未来，鉴于基于内燃机的汽车基础设施，以及化学工业将始终需要用于生产有机材料和化学品的原料的事实，而无论用于能源的是什么。[2]新的碳基燃料经济性面临的挑战是双重的：首先，碳源最终必须是大气中的二氧化碳，这是最实际的收获，通过光合作用生产纤维素，半纤维素，淀粉和单糖，其次，这些碳水化合物必须有效地转化为分子，这些分子是低挥发性和高能量含量的环境温度液体。在某种程度上，上述挑战目前正在通过从淀粉衍生的葡萄糖或蔗糖生产乙醇来应对，但这在很大程度上是一个权宜之计的问题，利用了在能源成为问题之前很久就建立的成熟技术（农业和酿酒厂/酿酒厂），现在许多人认为这种方法是过渡性的。[3]由于纤维素是光合作用固定碳的主要形式，因此可以认为它应该是任何新兴碳燃料技术的主要焦点。从乙醇生产的角度来看，困难在于可发酵糖不易从这种材料中释放出来。目前的纤维素利用模型涉及用固定化酶糖化，但尽管最近取得了进展，这仍然是一个缓慢和昂贵的过程。我们自己在这一领域的兴趣与纤维素水解问题关系不大，而与贫碳问题关系不大。
These are days of great incentive in the field of bioenergy research. The stakes, of course, are immense—economic independence from politically unstable, petroleum-exporting countries, the remediation of greenhouse gas levels in the atmosphere and their potential effect on the climate, and mitigation of the economic consequences of our imminent arrival at the Peak Oil point, particularly in light of the pace of industrialization of emerging economic superpowers in Asia. It may be said that the final answer to the global energy issue will lie most credibly in ultraclean technologies based on hydrogen and solar energy.[1] However, few would deny a more immediate future to carbon-based fuels, in view of the prevailing automotive infrastructure based on the internal combustion engine, as well as the fact that the chemical industry will always require feedstocks for the production of organic materials and chemicals, regardless of what is being used for energy.[2]The challenge to a new carbon-based fuel economy, as it emerges, is twofold: First, the carbon source must ultimately be atmospheric carbon dioxide, which is most practically harvested by the photosynthetic production of cellulose, hemicellulose, starch, and simple sugars, and second, these saccharides must be efficiently converted into molecules which are ambient temperature liquids of low volatility and high energy content. To some extent, the above challenge is currently being met by the production of ethanol from either starch-derived glucose or cane sugar, but this has largely been an issue of expediency, making use of mature technologies (agriculture and brewery/distillery) that were established long before energy became an issue, and the approach is now considered by many to be transitional.[3] Since cellulose is by far the major form of photosynthetically fixed carbon, it can be argued that it should be the principal focus of any emerging carbon-fuel technology. The difficulty, from the point of view of ethanol production, is that fermentable sugars are not easily liberated from this material. The current model for cellulose utilization involves saccharification with immobilized enzymes, but despite recent advancements, this remains a slow and expensive process. Our own interest in this area had less to do with the problems of cellulose hydrolysis than the poor carbon