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

这个PFI: AIR技术翻译项目的重点是改进和展示以最小的成本和能量投入从稀释生长培养物中恢复藻类生物量。该项目有可能导致从藻类生物质中提取的替代燃料的经济使用。缺乏低成本的藻类采集技术是目前微藻燃料商业化生产的主要瓶颈。当在开放的回旋池塘中培养时，微藻浓度非常低-通常为0.1%。刺激敏感水凝胶能够选择性地吸收大量培养基（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。与其他化学絮凝方法相比，这使得固体细胞从液体介质中以成本和节能的方式分离，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（从环境温度到35℃）轻松释放。回收（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，通过有效地回收水和未利用的水溶性营养物质，创造一个可持续的藻类收获过程。从研究发现到商业应用，该项目解决了以下技术差距：(i)在可扩展的原型中连续收集水凝胶，最大限度地减少凝胶的机械磨损，并保持凝胶的使用寿命；（二）利用废烟道气通过热整合使水凝胶消肿；（三）确立收集效率、可达到的最高培养浓度、收获产品质量和长期使用期间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设计、开发和测试基于水凝胶的藻类收获原型，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.