Microalgae are a non-food grade, fast-growing, and non-land competitive biomass with relatively high energy content. The high lipid and mineral contents of microalgae render it beneficial for the production of biofuels and value-added products. The complete energy-effective harnessing of microalgae potentials concerning biodiesel production is faced with drawbacks because of the energy-intensive steps required to harvest and dry microalgae. The limitations have impelled the search for alternative and low-cost utilization of microalgae in wet form for biofuel production. Anaerobic digestion (AD) is among the wet techniques for the valorization of microalgae that is gaining immense research attention because of its simplicity. Also, the products can be recycled to reduce material costs. This review is focused on the recent trends and comparison of the AD process to maximize energy recovery from microalgae biomass and co-digestion of microalgae waste coupled to biodiesel production (after lipid extraction), respectively. The yield of methane gas in these two processes is compared and the pros and cons of biogas production using microalgae biomass and microalgae waste considering that the former produces biofuels and the later value-added products are discussed.

微藻是非食品级，快速增长且非陆生竞争性生物质，具有相对较高的能量含量。微藻类的高脂质和矿物质含量使其对生物燃料和增值产品的生产有益。由于收获和干燥微藻需要耗费大量能量，因此与生物柴油生产有关的微藻潜能的完整能源有效利用面临着缺陷。这些局限性促使人们寻求以湿式形式的微藻替代和低成本利用以生产生物燃料。厌氧消化（AD）是用于微藻增值的湿法技术之一，由于其简单性而受到了广泛的研究关注。此外，产品可以回收利用以降低材料成本。这篇综述集中在AD趋势的最新趋势和比较上，以最大程度地从微藻生物质中回收能量以及微藻废料的共消化与生物柴油生产（脂质提取后）的共消化。比较了这两个过程中甲烷气的产率，并考虑了使用微藻生物质和微藻废料生产沼气的利弊，考虑到前者生产生物燃料，而后者则生产增值产品。