Simultaneous CO2 and biogas slurry treatment using a newly isolated microalga with high CO2 tolerance

[Display omitted] •Chlamydopodium sp. HS01 showed a strong resistance to biogas slurry (BS) and 15% CO2.•The alga exhibits significant efficiency in ammonia N removal and CO2 fixation.•The algal biomass produced had a great potential for bioenergy production.•The metabolome of HS01 underwent global changes responsed to 15% CO2 and BS togather.•It is the first report on curing 15% CO2 and BS together using Chlamydopodium sp. The fixation of carbon dioxide (CO2) using microalgae is a promising CO2 capture and utilization technology. Microalgae have also been suggested as a potential treatment for biogas slurry (BS). This study screened microalgae capable of tolerating both high CO2 concentrations and BS, assessed their CO2 fixation and pollutant removal capabilities, and evaluated the potential use of the resulting algal biomass. Chlamydopodium sp. HS01, which showed the highest tolerance to 15% CO2 and BS, was selected due to its strong growth, CO2 fixation, and ammonia nitrogen removal abilities. The generated biomass also demonstrated significant potential for bioenergy production. Metabolomics analysis revealed that the lipid composition of HS01 underwent substantial changes under 15% CO2 alone and in combination with BS, likely as a stress adaptation strategy. Overall, HS01 presents high potential for resource utilization of CO2 coupled with actual BS.