Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States.
Environ Sci Technol. 2023 Jan 17;57(2):1144-1156. doi: 10.1021/acs.est.2c04607. Epub 2023 Jan 4.
Conventional phototrophic cultivation for microalgae production suffers from low and unstable biomass productivity due to limited and unreliable light transmission outdoors. Alternatively, the use of a renewable lignocellulose-derived carbon source, cellulosic hydrolysate, offers a cost-effective and sustainable pathway to cultivate microalgae heterotrophically with high algal growth rate and terminal density. In this study, we evaluate the feasibility of cellulosic hydrolysate-mediated heterotrophic cultivation (Cel-HC) for microalgae production by performing economic and environmental comparisons with phototrophic cultivation through techno-economic analysis and life cycle assessment. We estimate a minimum selling price (MSP) of 4722 USD/t for producing high-purity microalgae through Cel-HC considering annual biomass productivity of 300 t (dry weight), which is competitive with the conventional phototrophic raceway pond system. Revenues from the lignocellulose-derived co-products, xylose and fulvic acid fertilizer, could further reduce the MSP to 2976 USD/t, highlighting the advantages of simultaneously producing high-value products and biofuels in an integrated biorefinery scheme. Further, Cel-HC exhibits lower environmental impacts, such as cumulative energy demand and greenhouse gas emissions, than phototrophic systems, revealing its potential to reduce the carbon intensity of algae-derived commodities. Our results demonstrate the economic and environmental competitiveness of heterotrophic microalgae production based on renewable bio-feedstock of lignocellulose.
由于室外光传输有限且不可靠，传统的光养微藻生产方法会导致生物量生产率低且不稳定。相比之下，使用可再生的木质纤维素衍生碳源——纤维素水解物，是一种具有成本效益且可持续的方法，可以异养培养微藻，实现高藻类生长速度和最终密度。在这项研究中，我们通过技术经济分析和生命周期评估，对纤维素水解物介导的异养培养（Cel-HC）生产微藻的可行性进行了经济和环境方面的评估，并与光养培养进行了比较。我们估计，通过 Cel-HC 生产高纯度微藻的最低销售价格（MSP）为 4722 美元/吨，考虑到 300 吨（干重）/年的生物量生产率，这与传统的光养跑道池塘系统具有竞争力。木质纤维素衍生的副产物木糖和腐殖酸肥料的收入可以进一步将 MSP 降低至 2976 美元/吨，这突出了在综合生物炼制厂方案中同时生产高价值产品和生物燃料的优势。此外，Cel-HC 比光养系统表现出更低的环境影响，如累计能源需求和温室气体排放，这表明它有潜力降低藻类衍生商品的碳强度。我们的研究结果表明，基于可再生生物原料木质纤维素的异养微藻生产具有经济和环境竞争力。
