微藻生物技术在碳中和的应用与展望

Application and Prospect of Microalgae Biotechnology in Carbon Neutralization

碳中和是指CO_(2)"零排放",在一段时间内通过节能减排、增加碳汇等途径,抵消各类活动所产生的CO_(2)的排放。微藻是含有叶绿素a的原生生物,可以利用太阳能通过浓缩机制(CCM)进行光合作用高效固定CO_(2)、通过异养同化作用转化固定有机碳。微藻生物质可转化为生物燃料、生物材料及生物肥料等,实现对传统化石燃料、塑料及化肥等的替代。生物技术应用涵盖了从上游的藻种选育、生长代谢过程的多组学调控、培养条件及光生物反应器的优化设计到下游的采收提取纯化及应用等微藻的全生命周期。以碳的收支为主线综述了微藻生物技术在碳中和领域的应用研究现状,讨论了其价值、意义及应用中存在的问题及改进方向。针对关键节点改善碳足迹,以实现微藻在碳中和领域更多应用。

Carbon neutralization means that the carbon dioxide emissions produced are offset,leading to carbon dioxide“zero emissions”within a certain period,through afforestation,energy conservation,and emission reduction.Microalgae is generally a term for the microorganism that contains chlorophyll a and can carry out photosynthesis.It has the characteristic property of being carbon neutral.It can efficiently fix carbon dioxide through the CO_(2)concentration mechanism(CCM)by photosynthesis and fix organic carbon through heterotrophic assimilation.The organic carbon recycling is coupled with microalgae cultivation by using nutrients in wastewater from sewage sludge,agriculture,or food industry.The new alternative and clean energy originated from microalgae includes biodiesel,alcohol-based fuel,hydrogen,and hydrocarbons.The biomass can be converted into biofuels,biomaterials,and biofertilizers to replace fossil fuels,plastics,and fertilizers.Biotechnology applications through the full life cycle include species selection,multi-omics regulation,cultivation in photobioreactors,harvesting,extraction,and purification of microalgae biomass or products.Herein,the application and research status of microalgae biotechnology in the field of carbon neutralization are reviewed based on the carbon balance between intake and output.The value,significance,existing problems,and improvement direction of microalgae biotechnology are discussed.The low efficiency and high energy consumption of cultivation,harvesting,and extraction process are the main cause of carbon footprint.The screening of suitable microalgal strains,regulating of metabolic pathways,optimizing of culture conditions and bioreactors,and optimizing of downstream processing(such as harvesting,extraction,and purification)with the purpose of increasing the efficiency of carbon sequestration and utilization efficiency of light energy are expected to reduce costs and improve carbon footprint.More applications of microalgae in carbon neutral fields can be realized by targeting key nodes to improve the carbon footprint.