PFI:AIR - TT: Low cost method for harvesting algal biomass from dilute cultures

这个PFI：空气技术转化项目的重点是以最低的成本和能量投入改进和演示从稀释型生长养殖中回收藻类生物量。该项目有可能导致经济地使用从藻类生物质中提取的替代燃料。目前，缺乏低成本的藻类采集技术是微藻燃料商业化生产的主要瓶颈。在露天跑道池塘养殖时，微藻浓度非常低--通常为0.1%。刺激敏感型水凝胶能够选择性地吸收大量的培养液(不吸收微藻细胞)，从而有效地提高微藻培养物的浓度，从而更有效地恢复微藻细胞。与竞争的化学絮凝方法相比，这允许以成本和能源高效的方式将固体细胞从液体介质中分离出来，而无需使用额外的化学品。此外，水凝胶中吸收的液体随后可以通过水凝胶温度的小幅升高(从环境温度提高到35°C)轻松释放。回收的(去膨胀的)水凝胶以及生长介质可以在多个循环中重复使用，通过水和未利用的水溶性营养的有效循环来创建可持续的藻类收获过程。该项目在将研究发现转化为商业应用的过程中解决了以下技术差距：(I)在可伸缩的原型中连续进行水凝胶采集，最大限度地减少凝胶受到机械磨损的暴露，并保持凝胶的寿命；(Ii)使用废气通过热集成来去膨胀水凝胶；(Iii)建立收获效率、可达到的最高培养浓度、收获产品的质量以及长期使用期间的水凝胶稳定性的基准。此外，参与该项目的本科生和研究生将通过水凝胶藻类采集原型的设计、开发和测试获得创新和技术转化经验。

This PFI: AIR Technology Translation project focuses on improving and demonstrating the recovery of algal biomass from dilute growth cultures with minimal cost and energy input. This project has the potential to lead to economical use of alternative fuels derived from algal biomass. The lack of low-cost technologies for harvesting algae is currently a major bottleneck in the commercial production of fuels from microalgae. When cultivated in open raceway ponds, microalgae concentrations are very low - typically 0.1%. Stimuli-sensitive hydrogels are capable of selectively soaking up large quantities of culture media (without absorbing microalgae cells), thus efficiently increasing concentrations of the microalgal cultures, leading to a more efficient recovery of the microalgal cells. This allows separation of solid cells from liquid media in a cost- and energy-efficient manner and without use of additional chemicals as compared to competing chemical flocculation methods. In addition, the absorbed liquid in the hydrogel can subsequently be released easily through small increases in hydrogel temperature (from ambient to 35°C). The recovered (de-swelled) hydrogels, as well as the growth medium, can then be reused over multiple cycles to create a sustainable algae harvesting process through effective recycling of water and un-utilized water-soluble nutrients.This project addresses the following technology gaps as it translates from research discovery toward commercial application: (i) continuous hydrogel harvesting in a scalable prototype that minimizes exposure of the gel to mechanical attrition and preserves gel longevity; (ii) use of waste flue gases to de-swell hydrogels through heat integration, (iii) establishes benchmarks for harvesting efficiency, highest culture concentrations achievable, quality of harvested product, and hydrogel stability during prolonged-use. In addition, undergraduate and graduate students involved in this project will receive innovation and technology translation experiences through design, development and testing of hydrogel-based algae harvesting prototypes.