Cellulose synthase complex configuration effects in microalgal cellulose

项目背景(确定问题及其对可持续性的重要性和相关性)由于目前的全球食品贸易，塑料包装已成为现代基础设施中必不可少的部分。然而，塑料，特别是一次性使用，正在造成负面的环境影响。使用后，只有14%的塑料被回收利用，32%的塑料被释放到环境中。塑料不能被生物因素降解，而是缓慢分解形成微塑料，积累在环境中，对人类和其他有机体造成损害。解决这场危机的一个办法是用生物塑料取代传统塑料材料。生物塑料是由可再生资源制成的塑料，如陆地作物、农业废弃物或快速生长的微生物。纤维素是自然界中含量最丰富的生物聚合物，由许多不同的生物合成。再生纤维素膜具有良好的阻隔功能、机械性能、生物降解性和可再生性，是食品包装的理想材料。然而，人们担心，在不占用种植粮食作物的空间或造成砍伐森林的情况下，从哪里可以可持续地获得大量纤维素。目前的纤维素来源也有一些属性需要改进，以用于各种包装材料。已经探索了许多纤维素来源，但微藻是一个特别感兴趣的研究不足的领域，因为它与其他形式的纤维素原料相比具有许多优势，包括纤维素结构的差异。建议的解决方案和方法将纤维素用于食品包装，有可能产生再生纤维素膜。这个过程是通过从宿主物种中提取纤维素，然后打破纤维素聚合物之间的键来进行的。然后，纤维素聚合物可以通过凝聚介质重塑成薄膜，使纤维素聚合物结合在一起，形成薄膜。微藻是具有不同纤维素结构的物种，可以为提取的纤维素提供独特的特性。形成纤维素的结构取决于纤维素合成酶复合体(末端复合体)的位置。在高等植物中，它们排列成六角形结构，称为莲座状结构。在微藻中，它们也可以排列成单行、多行或对角行。这种结构上的差异可能会赋予不同的物理化学性质，这将有助于创造出适用于不同应用的生物塑料或将其结合在一起用于多种目的。因此，研究藻类纤维素并将其创造成藻类薄膜可以提供多种好处，并有助于解决目前的塑料危机。实验的第一阶段将使用模型藻类普通小球藻开发一种成功的提取和成膜过程，该过程允许有利的成膜所需的结构分解，同时保留一些原始的纤维素结构。第二阶段将使用不同的藻类来源，呈现不同的纤维素合成酶复合体，并比较薄膜的结构和性能。最后一个阶段将是优化提取过程，以限制对环境的影响和使用藻类物种的薄膜的特性。然后，可以使用这些信息来扩大生产规模，以便在实际实践环境中使用。

Project background (identification of the problem and its importance and relevance to sustainability)Due to the current global food trade, plastic packaging has become essential in modern infrastructure. However, plastic, particularly single use, is causing negative environmental impacts. After use, only 14% of plastic is collected for recycling, with 32% being released into the environment. Plastic cannot be degraded by biotic factors and instead breaks down slowly to form microplastics that accumulate in the environment causing damage to humans and other organisms. One answer to this crisis is to replace conventional plastic materials with bioplastics. Bioplastics are plastic made from renewable resources, such as terrestrial crops, agricultural waste, or fast-growing microorganisms. Cellulose is the most abundant biopolymer in nature and is synthesised by many different organisms. Regenerated cellulose films could be ideal for food packaging due to their good barrier functionality, mechanical properties, biodegradability, and renewability. However, there are concerns about where a large amount of cellulose could be sourced sustainably without taking up space for growing food crops or causing deforestation. There are also some attributes of current cellulose sources which will need to be improved for use in a wide variety of packaging materials.Many cellulose sources have been explored, but micro-algae is an under-researched area of particular interest due to its many advantages to other forms of cellulosic feedstock, including differentiation in cellulose structure.Proposed solution and methodologyTo utilise cellulose for food packaging, it is possible to create regenerated cellulose films. The process occurs by extracting the cellulose from the host species then breaking the bonds between the cellulose polymers. The cellulose polymers can then be reformed into a film by a coagulation medium which allows the cellulose polymers to bond, forming a film.Micro-algae are species with different cellulose structures that may provide unique properties to the extracted cellulose. The structure in which the cellulose is formed depends on the position of the cellulose synthase complexes (Terminal Complexes). In higher plants, these are arranged in a hexagonal structure called a rosette structure. In microalgae, they can also be arranged as single rows, multiple rows, or diagonal rows. This difference in structure could impart different physicochemical properties, which would help create bioplastics for varying applications or combine for multiple purposes. Research into algal cellulose and its creation into algal films could therefore provide multiple benefits and help solve the current plastic crisis. The first phase of experimentation will be to use the model algae Chlorella vulgaris to develop a successful extraction and film formation process that allows for advantageous structural breakdown necessary for film formation whilst retaining some of the original cellulose structure. The second phase will be using diverse algal sources that present the different cellulose synthase complexes and compare the structure and the properties of the films. The final stage will be to optimise both the extraction process, to limit environmental impact and the properties of the film using algal species. This information can then be used for scaling up the production for use in the real-world practice setting.