湿藻油脂制备生物柴油的研究进展Progress on production of biodiesel from wet algal oil

利用含油量高、生长速度快及能净化环境的微藻转化制取生物燃料具备较大发展潜力，是实现“碳中和”和解决环境问题的有效途径之一。为了降低微藻制取生物柴油的能耗，利用湿法提取技术直接从湿藻生物质中提取油脂制备生物柴油成为研究热点，综述了传统细胞破壁提油酯交换法、原位酯交换法及新型水热破壁提油酯交换法3种湿藻油脂制备生物柴油的研究情况并分析了各自存在的问题。传统细胞破壁提油酯交换法需要有机溶剂提取油脂和酯交换两步实现生物柴油的制备，生产工艺复杂，生产投入较高。原位酯交换法可实现微藻生物质一步转化为生物柴油，但存在醇消耗量过大（酸催化原位酯交换）或高温高压能耗高（超临界醇原位酯交换）等问题。新型水热破壁提油酯交换法能够在不使用有机溶剂的情况下实现湿藻油脂的高效分离，但水热温度较高时油脂会与微藻其他组分反应导致油脂品质劣化，水热温度较低时难以有效破坏细胞壁导致油脂提取效率降低。绿色溶剂辅助水热法可有效降低水热温度并抑制副产物的生成，可提高湿藻油脂提取率。为实现湿藻油脂的高效、环保、低耗制备生物柴油，可进一步依托深共熔溶剂等创新绿色溶剂低耗高效绿色提取微藻油脂。The conversion of microalgae with high oil content, fast growth rate and environmental purification to produce biofuels has great development potential, which is one of the effective ways to achieve "carbon neutrality" and solve environmental problems. In order to reduce the energy consumption of microalgae preparation biodiesel, using wet extraction technology to directly extract oil from wet algae biomass for preparing biodiesel has been the research hotspot, three kinds of wet algae oil biodiesel preparation methods including traditional wall breaking for oil extraction and transesterification method, in situ transesterification method and new hydrothermal wall breaking for oil extraction and transesterification method were summarized and their existing problems were analyzed.The traditional wall breaking for oil extraction and transesterification method requires two steps of oil extraction with organic solvent and transesterification to realize the preparation of biodiesel，the production process is complex and the production input is high.In situ transesterification method can convert microalgal biomass into biodiesel in one step, but there are some problems such as excessive consumption of alcohol (acid catalytic in situ transesterification) or high energy consumption at high temperature and high pressure (supercritical alcohol in situ transesterification).The new hydrothermal wall breaking for oil extraction and transesterification method can realize the efficient separation of oil without using organic solvent. However, when the hydrothermal temperature is high, the reaction of oil and other components of microalgae can deteriorate the oil quality. When the hydrothermal temperature is low, it is difficult to effectively destroy the cell wall, resulting in low oil extraction efficiency.Green solvent-assisted hydrothermal method can effectively reduce the hydrothermal temperature and inhibit the generation of by-products, which can improve the extraction rate of wet algae oil. In order to realize the preparation of biodiesel with high efficiency, environmental protection and low energy consumption by wet algae oil, it can further rely on innovative green solvents such as deep eutectic solvent to achieve high efficiency,low consumption and green extraction of microalgae oil.