How do soluble enzymes from microbes degrade insoluble plant cell walls?

微生物的可溶性酶如何降解不溶性植物细胞壁？

• 批准号: 2888684
• 金额: --
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2888684
• 关键词: How; do; soluble; enzymes; microbes

BBSRC DTP main strategic theme: Bioscience for renewable resources and clean growthPlant cell walls are assembled with cellulose fibrils coated with hemicelluloses. The hemicellulose xylan is the most important and abundant hemicellulose in woody biomass and in grasses. Recent studies have shown that xylan changes its conformation into a flat two-fold screw ribbon to bind to the surface of cellulose. This functional form of xylan is inaccessible to conventional xylanases, since they require a soluble three-fold screw form for binding to the active site and hydrolysis. Current xylanase assays use extracted xylan or pretreated biomass that has altered the natural xylan conformations. In nature, microbes encounter xylan attached in the two-fold screw conformation, suggesting the natural degradation process might be somewhat different to measured assays.In this project we aim to understand how enzymes can effectively degrade the solid natural substrate. We will use holocellulose nanofibrils, which are cellulose coated with xylan in the natural conformation. These have been isolated recently in the Dupree lab. We will study the ability of different xylan-active enzymes to degrade the xylan coatings in the solid state. Such enzyme could include xylanases and also appendage-releasing enzymes such as acetyl esterases. We will study the activity using biochemical assays of released sugars, and also droplet-based assays that are coupled to degradation of the entire holocellulose.The project could involve some enzyme discovery, investigation of xylan degradation pathways, and also some enzyme characterisation.

BBSRC DTP主要战略主题：可再生资源和清洁生长植物细胞壁的生物科学与涂有半纤维素的纤维素原纤维组装在一起。半纤维素Xylan是木质生物质和草中最重要，最丰富的半纤维素。最近的研究表明，Xylan将其构象变成扁平的两倍螺丝丝带，以与纤维素的表面结合。这种功能性形式的木聚糖对常规的木聚糖酶无法访问，因为它们需要可溶的三倍螺钉形式才能结合活性位点和水解。当前的木聚糖酶测定使用提取的Xylan或预处理的生物量，该生物量改变了天然的Xylan构象。在自然界中，微生物遇到了两倍螺钉构象中附着的Xylan，这表明自然降解过程可能与测量的测定法可能有所不同。在该项目中，我们旨在了解酶如何有效地降解固体自然底物。我们将使用全纤维素纳米纤维，这些纳米纤维是在自然构象中涂有木兰的纤维素。这些最近在Dupree实验室中分离出来。我们将研究不同的Xylan活性酶在固态下降解Xylan涂层的能力。这种酶可能包括木聚糖酶以及添加剂释放酶，例如乙酰酯酶。我们将使用释放糖的生化测定法研究活性，还将基于液滴的测定法与整个全纤维素的降解相结合。该项目可能涉及一些酶发现，研究Xylan降解途径，以及一些酶特征。