Bioinspired hydrogels for improved cultivation of microalgal biomass

主题：农业和粮食安全摘要：微藻是生物圈的重要贡献者，产生了全球约75%的氧气需求，并在食物链和许多其他生态功能中发挥着不可估量的作用。除了它们的生态意义外，它们在许多行业也很重要，例如生物燃料和人类营养。然而，尽管有工业潜力，但目前的养殖方法阻碍了微藻生物技术在经济和环境上的可持续发展，这主要是因为普遍采用悬浮养殖方法，如跑道池塘。通过转换为固定化栽培技术，可以以更低的能源和水需求实现更高的生产率，而且占用的空间也更小。在这里，琼脂糖水凝胶被用作支架，将普通小球藻培养成生物膜。生物膜自然比悬浮栽培更有生产力，对水和能源的需求更低，同时也更容易收获。尽管固定化养殖有许多优点，但要使藻类技术可持续发展，仍需要提高许多效率。这里的重点是优化培养物的光合作用速率。通过添加散射颗粒，如纤维素纳米晶体，光衰减在整个培养过程中增加，创造更均匀的光照，减少细胞自身阴影，这反过来又提高了光合作用速率。如果能够克服目前的种植问题，如生产力低下，就可以以具有成本效益和可扩展的方式开发微藻，以实现其生物技术潜力。除此之外，还采用了一种机器学习的方法来理解单个细胞的光学响应与其生理之间的关系。生物质的数量和质量的测量是工业和科研中的一个重要步骤，例如脂肪含量或生长阶段。目前，对生物质的生化化合物含量，如色素或脂肪含量的定量，主要是通过化学提取来完成的，这是一种侵入性的过程，会破坏样品。通过机器学习，可以开发一种基于光学的非侵入性评估方法，以评估从色素含量到细胞大小分布和培养年龄的生物量质量。一旦在单细胞水平上理解了这一点，它将扩展到批量培养光学测量，作为一种原位、非侵入性的测量工具，用于表征培养物的生理特性。

Theme: Agriculture and Food SecuritySummary: Microalgae are an essential contributor to the biosphere, producing ~75% of the global oxygen demand as well as playing an invaluable role in the food chain among many other ecological functions. As well as their ecological significance, they are also important in many industries, such as biofuels and human nutrition. However, despite their industrial potential, current cultivation methods prevent microalgal biotechnology from being economically and environmentally sustainable, mainly due to the prevalence of suspended cultivation approaches, such as raceway ponds. By converting to an immobilised cultivation technique, higher productivity can be achieved with lower energy and water demands, also in a smaller space footprint. Here agarose hydrogels are used as a scaffold to grow Chlorella vulgaris as a biofilm. Biofilms are naturally more productive than suspended cultivation, have lower water and energy demands, while also being easier to harvest. Despite the advantages of immobilised cultivation there are still many efficiency improvements required to make algal based technology sustainable. Here the focus is optimising the photosynthetic rate of the culture. Through the addition of scattering particles, such as cellulose nanocrystals, light attenuation is increased throughout the culture, creating more even illumination and reducing cell self-shading, which in turn improves the photosynthetic rate. If the current cultivation issues, such as poor productivity, can be overcome, microalgae can be exploited to achieve their biotechnological potential in a cost-effective and scalable manner. Additional to this a machine learning approach is being taken to understand the correlation between the optical response of a single cell and its physiology. Measuring biomass quantity and quality is an important procedure both in industry and research, such as lipid content or growth stage. Quantifying the biochemical compound content of the biomass, for example pigment or lipid content, at present is mainly done by chemical extraction which is an invasive process and destroys the sample. By using machine learning, a non-invasive optical based assessment method to evaluate biomass qualities from pigment content to cell size distribution and culture age can be developed. Once this has been understood at a single cell level, it will be expanded to bulk culture optical measurements to act as an in-situ, non-invasive measurement tool for characterising a culture's physiological properties.