14CONFAP UNDERSTANDING CELL WALL STRUCTURE AND HYDROLYSIS OF TWO LEADING C4 BIOENERGY CROPS TO IMPROVE SECOND GENERATION BIOETHANOL PRODUCTION

摘要：从第一代(1G)生物乙醇过渡到以植物生物质为基础的更具生产力和可持续发展的生物经济，对于巴西保持清洁能源生产的领先地位、加强粮食和能源供应的安全、创造就业机会和减缓气候变化至关重要。从1G生物燃料过渡到第二代(2G)生物燃料的一个关键挑战是难以从细胞壁释放糖来生产具有经济可行性的生物乙醇。了解控制抗性的因素，设计细胞壁结构和水解酶以促进糖的释放，对于木质纤维原料的商业开发和生物经济概念的实现至关重要。另一个重要方面是发展生物质作物，在不适合种植粮食作物的缺水环境中保持生物质生产力和质量。在预测气候变化的情况下，这一方面甚至更加重要，我们需要迅速使作物适应具有挑战性的环境条件。活动包括在合作伙伴之间整合的网络、研究和景观范围活动，涉及三个不同的工作包：WP1：与原料和前处理相匹配的量身定制的酶鸡尾酒。在这一为期一年的裁决框架内，目的是提供关于鸡尾酒-原料-预处理匹配潜力的初步数据。目前的商业酶是基于一刀切的方法。由于酶是生物质加工成本的主要贡献者，因此为特定的前处理和原料量身定做定制的酶鸡尾酒将减少酶的负载量，从而降低加工成本。这份可湿性粉剂将为将酶鸡尾酒与原料和前处理相匹配的巨大潜力提供概念证明。WP2：设计未来的水解酶和原料。合成生物学提供了令人兴奋的工程机会，以促进从植物细胞壁生物质中释放糖。一个例子是“生物预处理”，这是一个基于开发和重新设计植物中已经发生的一些内源水解酶和过程的概念。另一个有吸引力的策略是通过在植物中表达耐热的细胞壁降解酶来改善细胞壁的解构。我们将组织一次研讨会，有效地捕捉这种合成生物学方法的潜力，并制作一份基于工程理想模式的战略文件，既适用于植物解构，也适用于多功能水解酶。这一一揽子工作的成果为进一步在植物细胞壁领域实施合成生物学方法奠定了基础，并将使合作伙伴处于这一新兴研究领域的前沿。WP3：环境和遗传因素对细胞壁生物量质量和转化的影响。细胞壁生物量的组成和结构可能因组织、物种、品种和环境条件的不同而显著不同。在气候变化和开发适合在边际土地上种植的甘蔗品种的背景下，绘制生物量质量的变化图尤为重要。细胞壁表型数据与糖化分析数据的整合将提供关于生物质组织、品种/遗传和环境条件的差异如何影响细胞壁质量和生物量对其组成糖的解构的基本信息。这一受控环境试验的结果为今后以利用巴西现有边际土地为重点的实地试验研究的翻译和设计提供了一个平台。

Summary: The transition from first-generation (1G) bioethanol to a more productive and sustainable bioeconomy based on plant biomass is essential for Brazil to remain at the forefront in clean energy production and to strengthen security of food and energy supplies, create jobs, and mitigate climate change. A key challenge associated with the transition from 1G to second-generation (2G) biofuels is the difficulty to release sugars from cell walls to produce bioethanol with economic viability. Understanding the factors that govern recalcitrance and engineering cell wall architectures and hydrolytic enzymes for enhanced sugar release is crucial for the commercial exploitation of lignocellulosic feedstocks and realization of the bio-economy concept. Another important aspect is the development of biomass crops that maintain biomass productivity and quality under water-scarce environments unsuited for growing food crops. This aspect is even more important in a scenario of predicted climate change, where we need to quickly adapt crops to challenging environmental conditions. Activities comprise a mix of networking, research and landscape-scoping activities, integrated between the partners, across three different work packages:WP1: Tailored enzyme cocktails matching feedstock & pretreatment. The aim within the framework of this 1-year award will be to provide preliminary data on the potential of cocktail-feedstock-pretreatment matching. Current commercial enzymes are based on the one-size-fits-all approach. Since enzymes are a major contributor to biomass processing costs, creating customized enzyme cocktails that are tailored to specific pretreatments and feedstocks, will reduce enzyme loading and therefore processing costs. This WP will deliver proof of concept for the enormous potential of matching enzyme cocktails to feedstock and pretreatment. WP2: Engineering the hydrolytic enzymes and feedstocks of the future. Synthetic biology offers exciting engineering opportunities to facilitate the release of sugars from plant cell wall biomass. One example is that of "biological pretreatment", a concept based on exploiting and redesigning some of the endogenous hydrolytic enzymes and processes already taking place in plants. Another attractive strategy to improve cell wall deconstruction is through the in planta expression of thermostable cell wall degrading enzymes. We will organize a workshop to effectively capture the potential of such synthetic biology approaches and produce a strategy document based around engineered ideotypes for both "in planta deconstruction" and "multifunctional hydrolytic enzymes". The outcomes of this work-package provides the foundation for further implementation of synthetic biology approaches in the area of plant cell walls and will position the partners at the forefront of this emerging research area.WP3: Effect of environmental and genetic factors on cell wall biomass quality and conversion. The composition and architecture of cell wall biomass can differ significantly depending on tissue, species, cultivar, and environmental conditions. Mapping variations in biomass quality is particularly important in the context of climate change and developing sugarcane varieties suitable for cultivation on marginal land. The integration of cell wall phenotyping data with those from saccharification assays will provide essential information on how differences in biomass tissue, varieties/genetics, and environmental conditions impact on cell wall quality and biomass deconstruction into its components sugars. The outcomes of this controlled environment experiment represent a platform for the translation and design of future field trial studies focussing on utilizing marginal land available in Brazil.