Digestates from different anaerobic digesters are promising substrates for microalgal culture, leading to effective wastewater treatment and the production of microalgal biomass. However, further detailed research is needed before they can be used on a large scale. The aims of this study were to investigate the culture ofChlorellasp. in DigestateMfrom anaerobic fermentation of brewer’s grains and brewery wastewater (BWW) and to explore the potential use of the biomass produced under different experimental conditions, including diverse cultivation modes and dilution ratios. Cultivation in DigestateMinitiated from 10% (v/v) loading, with 20% BWW, obtained maximum biomass production, reaching 1.36 g L−1that was 0.27g L−1higher than 1.09 g L−1of BG11. In terms of DigestateMremediation, the maximum removal of ammonia nitrogen (NH4+-N), chemical oxygen demand, total nitrogen, and total phosphorus reached 98.20%, 89.98%, 86.98%, and 71.86%, respectively. The maximum lipid, carbohydrate, and protein contents were 41.60%, 32.44%, and 27.72%, respectively. The growth ofChlorellasp. may be inhibited when the Y(II)–Fv/Fmratio is less than 0.4.