Progress and Challenges in Microalgal Biodiesel Production.
Progress and Challenges in Microalgal Biodiesel Production.
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DOI：
10.3389/fmicb.2016.01019
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发表时间：
2016
影响因子：
5.2
通讯作者：
Singh AK
中科院分区：
文献类型：
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作者：
Mallick N;Bagchi SK;Koley S;Singh AK
过去的十年见证了生物燃料研究的巨大推动力，这是由于化石燃料储量的不可逆转的减少，以满足运输的巨大需求，而绿色家用气体（GHG）的排放量不断增加。随着CO2减排的迫切需要和原油地位的下降，各国政府不仅将大量资金用于生物燃料项目，而且还对生产生物燃料的供应商采取了激励措施。目前，从微藻生物质生产生物柴油已经引起了极大的重视，有可能排除高质量的农业土地使用和粮食安全保存问题。此外，微藻可以在海水或废水中生长，并且微藻油可以超过50-60%（细胞干重），而一些最好的农业油料作物的含油量仅为5-10%。在全球范围内，微藻是最高的生物质生产者和中性脂质生产者，与任何其他陆地油料作物竞争。然而，在每一个步骤中仍然存在许多障碍，从菌株选择和脂质积累/产量开始，藻类大量培养，然后是下游过程，如收获、干燥、油提取和生物柴油转化（酯交换），以及总的来说，生产成本。产油微藻的分离筛选是一个重要的上游因素，应根据淡水或海洋藻类的需要加以解决，并考虑野生型土著分离物最适合实验室大规模开发。目前，关于微藻生物柴油生产的研究文献很多，但没有一个详细地描述微藻生物柴油生产的上下游过程的利弊。具体而言，收获和干燥占总生产成本的50%以上;然而，可获得的详细研究报告数量较少。本文对产油微藻的分离筛选、规模化培养、生物质收获、干燥、油脂提取及生物柴油生产等方面的研究进展进行了综述。
The last decade has witnessed a tremendous impetus on biofuel research due to the irreversible diminution of fossil fuel reserves for enormous demands of transportation vis-a-vis escalating emissions of green house gasses (GHGs) into the atmosphere. With an imperative need of CO2 reduction and considering the declining status of crude oil, governments in various countries have not only diverted substantial funds for biofuel projects but also have introduced incentives to vendors that produce biofuels. Currently, biodiesel production from microalgal biomass has drawn an immense importance with the potential to exclude high-quality agricultural land use and food safe-keeping issues. Moreover, microalgae can grow in seawater or wastewater and microalgal oil can exceed 50–60% (dry cell weight) as compared with some best agricultural oil crops of only 5–10% oil content. Globally, microalgae are the highest biomass producers and neutral lipid accumulators contending any other terrestrial oil crops. However, there remain many hurdles in each and every step, starting from strain selection and lipid accumulation/yield, algae mass cultivation followed by the downstream processes such as harvesting, drying, oil extraction, and biodiesel conversion (transesterification), and overall, the cost of production. Isolation and screening of oleaginous microalgae is one pivotal important upstream factor which should be addressed according to the need of freshwater or marine algae with a consideration that wild-type indigenous isolate can be the best suited for the laboratory to large scale exploitation. Nowadays, a large number of literature on microalgal biodiesel production are available, but none of those illustrate a detailed step-wise description with the pros and cons of the upstream and downstream processes of biodiesel production from microalgae. Specifically, harvesting and drying constitute more than 50% of the total production costs; however, there are quite a less number of detailed study reports available. In this review, a pragmatic and critical analysis was tried to put forward with the on-going researches on isolation and screening of oleaginous microalgae, microalgal large scale cultivation, biomass harvesting, drying, lipid extraction and finally biodiesel production.