Chlorella sp. treatment of liquid digestates from Humulus scandens by phycoremediation coupled with high value-added biomass production

Effluents derived from anaerobic digesters are sustainable sources for the cultivation of microalgae, which not only effectively treats digestate but also yields valuable raw materials for bio-based products. Humulus scandens fermented liquid (HSFL) was initially utilized for cultivating Chlorella sp. and has proven to be a promising medium for microalgal cultivation. However, further research is required before large-scale applications of both H. scandens digestate (HSD) and HSFL can be established. This study investigated the cultivation of Chlorella sp. within HSD and HSFL and investigated the possible utilization of the biomass generated under various experimental conditions, including different culture patterns and dilution proportions. The biomass dry weight concentration reached its maximum when it was cultivated in 15% HSFL. It reached 1.28 g L−1, which was 0.10 g L−1 higher than the 1.18 g L−1 obtained in BG11. In terms of HSD remediation, the maximum removal rates of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) reached 91.75%, 76.25%, and 92.58%, respectively. The maximum protein, carbohydrate, and lipid contents were 20.01%, 27.68%, and 43.88%, respectively.