microalgae is one of the photoautotrophic microorganisms that has attracted significant attention in wastewater treatment and biofuel production. although researchers claimed that microalgae cultivation in wastewater treatment has a very high potential for nutrient removal and economic benefit from downstream production, microalgae brought drawbacks such as extra cost and energy consumption due to diluted concentration, lower effluent quality because of suspended biomass, and risk of contamination by bacteria. biofilm cultivation is considered an alternative to overcome the prementioned disadvantages. furthermore, involving membrane technology in biofilm cultivation could further promote biomass harvesting efficiency and effluent quality. thus, the new biofilm membrane bioreactors such as membrane carbonated microalgal biofilm reactor (mcmbr), and extractive membrane microalgal biofilm reactor (emmbr) should have great prospects in sewage treatment. [...]