Abstract

Carbon capture and utilization (CCU) is an emerging technology with commercial potential to convert atmospheric carbon dioxide (CO₂) into net zero or negative emission products. In microalgae-based CCU, microalgae utilize CO₂ and sunlight to generate biomass for commercial applications. This paper reviews the current state of microalgal culture development for CCU and highlights its potential contribution to addressing climate change challenges. Current microalgal culture systems have not been designed for high throughput biomass growth and carbon capture. Raceways, high-rate algal ponds, and photobioreactors are the most widely used for microalgal cultivation at a large-scale. The limitations of these systems are related to microalgal growth requirements. Ponds are operated at narrow depth to ensure sufficient light distribution and thus need a large land surface. CO₂ gas needs to be in a dissolved form for efficient utilization by microalgae. Innovative system designs to achieve optimized distribution of light, nutrient, and CO₂ utilization for enhanced biomass production are crucial to achieve large-scale CO₂ capture by microalgae. Data corroborated in this review highlights several innovative techniques to deliver CO₂ effectively and enhance light illumination to microalgal cells. Submerged and internal illuminations can enhance light distribution without compromising culture volume and land requirements. CO₂ delivery technique selections mainly depend on CO₂ sources. The carbonation column appears to be the best option regarding efficiency, easy operation, and simple design. The downstream processes of microalgal culture (i.e. harvesting, biomass utilization, and water reuse) are important to make microalgae-based CCU a significant contribution to global carbon mitigation solutions.

摘要

碳捕获和利用 (CCU) 是一项具有商业潜力的新兴技术，可将大气中的二氧化碳 (CO ₂ ) 转化为净零排放或负排放产品。在基于微藻的 CCU 中，微藻利用 CO ₂和阳光来产生用于商业应用的生物质。本文回顾了 CCU 微藻培养发展的现状，并强调了其对应对气候变化挑战的潜在贡献。目前的微藻培养系统尚未设计用于高通量生物质生长和碳捕获。水道、高速率藻类池塘和光生物反应器是最广泛用于大规模微藻培养的。这些系统的局限性与微藻生长要求有关。池塘在较窄的水深下运行以确保充足的光分布，因此需要较大的陆地表面。CO ₂气体需要以溶解的形式被微藻有效利用。创新的系统设计可实现光、养分和二氧化碳的优化分配₂利用提高生物质生产对于实现微藻大规模 CO ₂捕获至关重要。这篇综述中证实的数据重点介绍了几种有效输送 CO ₂并增强微藻细胞光照的创新技术。淹没和内部照明可以增强光分布，而不会影响培养体积和土地要求。CO ₂输送技术选择主要取决于CO ₂来源。碳酸化塔似乎是效率高、操作方便和设计简单的最佳选择。微藻培养的下游过程（即收获、生物质利用和水回用）对于使基于微藻的 CCU 成为全球碳减排解决方案的重要贡献非常重要。