[16- FAPESP-BE] An integrated approach to explore a novel paradigm for biofuel production from lignocellulosic feedstocks

[16- FAPESP-BE] 探索木质纤维素原料生产生物燃料新范例的综合方法

基本信息

批准号：
BB/P017460/1
负责人：
David Jonathan Leak
金额：
$ 189.99万
依托单位：
University of Bath
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FP017460%2F1
关键词：
16 FAPESP integrated approach explore

项目摘要

Climate change is being driven, at least partly, by the burning of fossil fuels and consequent CO2 release into the environment. To mitigate this we need to produce more fuels/chemicals from renewable resources. One globally relevant abundant resource is lignocellulose (present in wood, straw, grasses and in many waste streams) and efforts are being made to exploit this efficiently. However, current processes have inherent inefficiencies due to the limitations of yeast, the most common organism used in biofuel fermentations. Yeasts are good at converting simple sugars such as glucose and sucrose to ethanol, but natural strains cannot metabolise xylose, which is abundant in lignocellulose, or longer chains of sugars (oligosaccharides). This means that for yeast fermentations it is necessary to break down the lignocellulose to simple monomeric sugars for them to be utilised effectively. This approach generally requires harsh physico-chemical pre-treatment methods which, increase the energy demand of the process and produce compounds that can inhibit the subsequent fermentation. Thus it is often necessary to remove these inhibitors, which adds expense to the process. In this project we intend to demonstrate that it is more sensible (logical and economic) not to pre-treat lignocellulose so harshly, and have a more "holistic" approach to the process: delivering the desired products whilst minimising overall process energy and cost by working on the optimisation of generating partial breakdown products and ensuring that the subsequent fermentation organism is able to convert these directly to product.The most commonly employed class of fermentation organisms - yeasts - will be engineered to be able to convert the oligomeric sugars directly. However, there is a class of organisms - Geobacillus - that have been quite extensively studied by one of the UK groups, which already naturally has the propensity to utilise oligomeric sugars and can also be readily engineered to optimise key metabolic pathways. Therefore, in this project we will use a representative of this group of bacteria to compare performance with the engineered yeast.We also propose to consider three different lignocellulosic feedstocks in this study, all of which have the potential to be used for sustainable fuels and chemicals production: Brazilian cane straw - which is current left in the fields after harvesting, Miscanthus - which is grown in the UK for burning in power stations (co-firing) and has a lot of similarities to cane straw, and Eucalyptus forestry residues, which are abundant in Brazil and represent a different type of opportunity and material to evaluate. Some of the team involved will focus on developing methods to convert these to oligosaccharides that can be taken up by these new strains. This will be a combination of less severe (than currently) pre-treatment and the use of selected enzymes to produce the oligo-saccharides required. Another part of the team will focus on producing the enzymes required for these conversions to oligosaccharides, while a third group will engineer the yeast strains to use oligosaccharides of both xylose and glucose.To increase the energy efficiency of the feedstocks in the new lignocelulose mills we are going to recover chemicals and biogas from the liquid effluents, vinasse and hemicellulose hydrolysates, by integrating anaerobic digestion (AD) to the process. AD with mixed culture fermentation will improve the energy ratio bringing biogas production and fertilizers as products.Underpinning all this is the need to ensure that the outputs of this work remains relevant to the industry processes that they potentially feed into. Therefore we have a team of LCA experts ensuring that feedstock/ product choice is appropriate, that the proposed process optimisation approaches are delivering a positive impact on process performance and pinpointing where further changes/modifications could be made.

气候变化至少部分是由于化石燃料的燃烧以及随之而来的CO2释放到环境中的驱动。为了减轻这种情况，我们需要从可再生资源中生产更多的燃料/化学物质。全球相关的丰富资源是木质纤维素（存在于木材，稻草，草和许多废物流中），并正在努力有效利用这种利用。但是，由于酵母菌的局限性，酵母是生物燃料发酵中最常见的生物，因此当前的过程具有固有的效率低下。酵母擅长将简单的糖（例如葡萄糖和蔗糖）转化为乙醇，但天然菌株不能代谢木糖，该木糖量在木质纤维素中丰富，或糖的链链较长（寡糖）。这意味着，对于酵母菌发酵，必须将木质纤维素分解为简单的单体糖，以便有效利用它们。这种方法通常需要严厉的物理化学预处理方法，从而增加过程的能量需求并产生可以抑制随后发酵的化合物。因此，通常有必要去除这些抑制剂，这增加了过程的费用。在这个项目中，我们打算证明，更明智的（逻辑和经济）不要如此严厉地预处理木质纤维素，并在过程中采用更“整体”的方法：提供所需的产品，同时最大程度地减少整体过程能源和成本。致力于优化生成部分分解产品，并确保随后的发酵生物能够直接转化为产品。最常用的发酵生物类别（酵母）将被设计为能够直接转化寡聚糖。但是，有一类生物体 - 地理芯片 - 由英国一个群体进行了非常广泛的研究，它们自然具有利用寡糖糖的倾向，并且也很容易地设计以优化关键的代谢途径。因此，在这个项目中，我们将使用这组细菌的代表将性能与工程酵母进行比较。我们还建议在这项研究中考虑三种不同的木质纤维素原料，所有这些都有可能用于可持续燃料和化学物质的潜力生产：收获后的巴西甘蔗稻草 - 在收获后剩下的田野中，该甘蔗在英国种植，该稻草是在英国生长的，用于在电站燃烧（共同射击），并且与甘蔗稻草和桉树林的残留物有很多相似之处在巴西很丰富，代表了不同类型的机会和评估材料。涉及的一些团队将专注于开发这些方法将这些方法转换为寡糖，这些方法可以由这些新菌株占用。这将是严重（比目前）预处理较少的组合以及所选酶产生所需的寡糖的组合。团队的另一部分将专注于生产这些转化为寡糖所需的酶，而第三组将设计酵母菌菌株以使用木糖和葡萄糖的寡糖。为了提高新木质纤维素磨机中原料的能量效率，我们通过将厌氧消化（AD）整合到该过程中，将从液体废水，vinasse和半纤维素水解物中回收化学物质和沼气。具有混合培养发酵的广告将提高能量比，从而将沼气生产和肥料作为产品带来。在所有这些方面，所有这些都需要确保这项工作的产出与他们潜在的行业流程保持相关。因此，我们有一个由LCA专家组成的团队，以确保原料/产品选择合适，拟议的过程优化方法对过程性能产生了积极的影响，并确定了可以进行进一步的更改/修改。