Microalgae have gained considerable attention as an alternative feedstock for the biofuel production, particularly in combination with genetic modification strategies that target enhanced lipid productivity. To tackle climate change issues, phasing out the usage of fossil fuels is seen as a priority, where the utilization of biofuel from microalgae serves as a potential sustainable energy source for various applications. These photosynthetic microalgae utilize solar energy and carbon dioxide to produce energy-rich compounds (i.e., starch and lipids), that can be further converted into biofuels of different types. Among different types of biofuels, biodiesel from the transesterification of triacylglycerols stands out as the most sustainable replacement of transportation fuel over fossil-based petroleum diesel. However, hurdles such as limited productivity, overall production cost and challenges in upscaling the algal technology leaves a huge gap on the road to commercialized microalgae-based biofuel. This review article first presents a comprehensive overview of imperative knowledge regarding microalgae in terms of algal classification, factors affecting the growth of microalgae during cultivation and different steps in upstream processing. This review also discusses recent advances in downstream processing of microalgal biorefinery. Additionally, this review paper focuses on deliberating various recent strategies of genetic modifications and their feasibility for enhanced lipid productivity in microalgae. Finally, the current challenges and future perspectives of microalgae-based biofuels are highlighted in this review discussing several aspects, including sustainability of microalgae-based biofuel production, current status of algae-based industry, risks and legislation considerations of genetic modification of microalgae.

微藻作为生物燃料生产的替代原料受到了相当大的关注，特别是结合以提高脂质生产力为目标的基因改造策略。为了应对气候变化问题，逐步淘汰化石燃料的使用被视为优先事项，其中利用微藻类生物燃料作为各种应用的潜在可持续能源。这些光合微藻利用太阳能和二氧化碳生产富含能量的化合物（即淀粉和脂质），这些化合物可以进一步转化为不同类型的生物燃料。在不同类型的生物燃料中，三酰甘油酯交换产生的生物柴油脱颖而出，是替代化石石油柴油的最可持续的运输燃料。然而，有限的生产力、总体生产成本和升级藻类技术的挑战等障碍在微藻生物燃料的商业化道路上留下了巨大的差距。这篇评论文章首先从藻类分类、培养过程中影响微藻生长的因素以及上游加工的不同步骤等方面全面概述了有关微藻的必要知识。本综述还讨论了微藻生物精炼下游加工的最新进展。此外，这篇评论文章重点讨论了最近的各种基因改造策略及其提高微藻脂质生产力的可行性。最后，这篇综述强调了微藻生物燃料当前面临的挑战和未来前景，讨论了几个方面，