New tools for the realization of cost-effective liquid biofuels from plant biomass (revised costs)

从植物生物质中实现具有成本效益的液体生物燃料的新工具（修订成本）

• 批准号: BB/G016208/1
• 负责人: Simon Cragg
• 金额: $ 56.03万
• 依托单位: University of Portsmouth
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FG016208%2F1
• 关键词: New; tools; realization; cost; effective

The production of liquid biofuels from lignocellulosic biomass offers the potential to provide liquid transportation fuels in an environmentally benign manner without compromising food security. Lignocellulose is largely composed of polysaccharides that can be converted into simple sugars and used to produce alcohols such as ethanol and butanol by microbial fermentation. Production of such liquid biofuels from plant biomass is currently hampered by the cost of converting lignocellulose into fermentable sugars (saccharification). There is a clear need for new and better enzymes for lignocellulose saccharification. A number of animals such as termites can survive on a diet of lignocellulose, suggesting they have overcome the problem of obtaining sugars from this recalcitrant substrate. These organisms generally rely on a population of bacteria and protists in their digestive tract that help to digest the lignocellulose. An exception to this rule is found in the Limnoriidae (also known as gribble), small crustacean wood borers from the marine environment. These animals can survive on a diet of lignocellulose and are unusual in having an effectively sterile digestive tract. This suggests that not only can Limnoria digest lignocellulose with their own enzymes, but that conditions within the digestive tract, associated with lignocellulose digestion, prevent microbes from becoming established. The unusual nature of lignocellulose digestion in Limnoria indicates a great potential for uncovering new insights and approaches to saccharification and new enzymes and genes for industrial applications. By analogy, the termite digestive tract can be seen as a complex microbial reactor for lignocellulose digestion, whereas the Limnoria gut is an enzyme reactor, and thereby much closer in its nature to current industrial systems. We have used deep transcriptomic sequencing of the digestive tract of Limnoria in order to reveal the genes expressed during lignocellulose breakdown. We sequenced more than 280,000 cDNAs revealing a breathtaking insight into this process. The Limnoria gut transcriptome is dominated by genes encoding several major classes of protein. Genes encoding glycosyl hydrolases (enzymes that convert polysaccharides into sugars) account for almost 30% of cDNAs, and putative cellulases and cellobiohydrolases (including some never before seen before in animal genomes) account for almost 25% of the transcriptome. A number of other protein classes are represented at very high abundance suggesting they may be involved in the digestive process. The programme of work presented here aims to identify the key mechanisms and components of lignocellulose digestion in Limnoria, in order that we can apply principles and enzymes from this process in order to enhance industrial lignocellulose saccharification. To better determine the roles of particular proteins in the digestive process we will establish whether or not they are secreted into the gut lumen where digestion occurs. We will produce recombinant versions of the enzymes, characterise their enzymatic properties and determine their usefulness for lignocellulose saccharification both using individual enzymes as well as combinations. We will also establish whether expressing the genes encoding these enzymes can be used to improve the saccharification potential of lignocellulosic biomass in energy crops.

从木质纤维素生物质生产液体生物燃料提供了以环境友好的方式提供液体运输燃料而不损害粮食安全的潜力。木质纤维素主要由多糖组成，多糖可以转化为单糖，并用于通过微生物发酵生产醇类，如乙醇和丁醇。从植物生物质生产这种液体生物燃料目前受到将木质纤维素转化为可发酵糖（糖化）的成本的阻碍。显然需要新的和更好的酶用于木质纤维素糖化。许多动物，如白蚁，可以在木质纤维素的饮食中生存，这表明它们已经克服了从这种木质纤维素基质中获得糖的问题。这些生物体通常依赖于其消化道中的细菌和原生生物群体来帮助消化木质纤维素。这一规则的一个例外是在Limnoriidae（也称为gribble）中发现的，这是一种来自海洋环境的小型甲壳类木材钻孔机。这些动物可以靠木质纤维素的饮食生存，并且具有有效无菌的消化道。这表明，不仅Limnoria可以用自己的酶消化木质纤维素，而且与木质纤维素消化相关的消化道内的条件阻止微生物建立。Limnoria中木质纤维素消化的不寻常性质表明了揭示糖化新见解和方法以及用于工业应用的新酶和基因的巨大潜力。通过类比，白蚁消化道可以被视为用于木质纤维素消化的复杂微生物反应器，而Limnoria肠道是酶反应器，因此在其性质上更接近于当前的工业系统。我们已经使用了深度转录组测序的消化道的Limnoria，以揭示在木质纤维素分解过程中表达的基因。我们对超过280，000个cDNA进行了测序，揭示了对这一过程的惊人见解。Limnoria肠道转录组由编码几种主要蛋白质的基因主导。编码糖基水解酶（将多糖转化为糖的酶）的基因占cDNA的近30%，推定的纤维素酶和纤维二糖水解酶（包括一些以前从未在动物基因组中见过的酶）占转录组的近25%。许多其他蛋白质类以非常高的丰度表示，表明它们可能参与消化过程。这里提出的工作计划旨在确定Limnoria中木质纤维素消化的关键机制和组分，以便我们可以应用该过程的原理和酶，以提高工业木质纤维素糖化。为了更好地确定特定蛋白质在消化过程中的作用，我们将确定它们是否分泌到消化发生的肠腔中。我们将生产酶的重组版本，验证它们的酶性质，并确定它们对木质纤维素糖化的有用性，无论是使用单个酶还是组合酶。我们还将确定表达编码这些酶的基因是否可用于提高能源作物中木质纤维素生物质的糖化潜力。

项目成果

Biogeography of wood-boring crustaceans (Isopoda: Limnoriidae) established in European coastal waters.

• DOI: 10.1371/journal.pone.0109593
• 发表时间: 2014
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Borges LM;Merckelbach LM;Cragg SM
• 通讯作者: Cragg SM

The complete mitochondrial genome of Limnoria quadripunctata Holthuis (Isopoda: Limnoriidae)

• DOI: 10.3109/19401736.2013.855912
• 发表时间: 2015-11
• 期刊: Mitochondrial DNA
• 作者: Rhiannon E. Lloyd;S. Streeter;P. Foster;D. Littlewood;Jim J. Huntley;G. Beckham;M. Himmel;S. Cragg

Hemocyanin facilitates lignocellulose digestion by wood-boring marine crustaceans.

• DOI: 10.1038/s41467-018-07575-2
• 发表时间: 2018-12-03
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: Besser K;Malyon GP;Eborall WS;Paro da Cunha G;Filgueiras JG;Dowle A;Cruz Garcia L;Page SJ;Dupree R;Kern M;Gomez LD;Li Y;Elias L;Sabbadin F;Mohamad SE;Pesante G;Steele-King C;Ribeiro de Azevedo E;Polikarpov I;Dupree P;Cragg SM;Bruce NC;McQueen-Mason SJ
• 通讯作者: McQueen-Mason SJ

Uncovering the molecular mechanisms of lignocellulose digestion in shipworms.

• DOI: 10.1186/s13068-018-1058-3
• 发表时间: 2018
• 期刊: Biotechnology for biofuels
• 影响因子: 6.3
• 作者: Sabbadin F;Pesante G;Elias L;Besser K;Li Y;Steele-King C;Stark M;Rathbone DA;Dowle AA;Bates R;Shipway JR;Cragg SM;Bruce NC;McQueen-Mason SJ
• 通讯作者: McQueen-Mason SJ

Lignocellulose degradation mechanisms across the Tree of Life.

• DOI: 10.1016/j.cbpa.2015.10.018
• 发表时间: 2015-12
• 期刊: Current opinion in chemical biology
• 影响因子: 7.8
• 作者: Cragg SM;Beckham GT;Bruce NC;Bugg TD;Distel DL;Dupree P;Etxabe AG;Goodell BS;Jellison J;McGeehan JE;McQueen-Mason SJ;Schnorr K;Walton PH;Watts JE;Zimmer M
• 通讯作者: Zimmer M