Pre-treatment options for halophytic microalgae and associated methane production

•All anaerobic digestion successful at 7% salinity (2× seawater salinity).•Methane production rate of 122 mL per g VS for lipid extracted Tetraselmis sp.•Methane production rate of 252 mL per g VS for non-disrupted Tetraselmis sp.•Methane production rate of 248 mL per g VS for pretreated disrupted Tetraselmis sp.•Microbial degradation of Tetraselmis sp. demonstrated during anaerobic digestion.

Methane production from lipid extracted, pre-treated disrupted and non-pretreated Tetraselmis spp. microalgae was investigated. The results demonstrated that 122 mL per g VS methane was produced for the lipid extracted Tetraselmis spp., demonstrating that lipid free Tetraselmis can be effectively digested in an anaerobic environment. A total of 252 mL per g VS and 248 mL per g VS of methane was reported for non-disrupted and pre-treated disrupted Tetraselmis sp. respectively. It was also observed that the microbial community caused cell lysis of Tetraselmis spp. during the anaerobic digestion process. Cell lyses can offer a direct conversion pathway of intact Tetraselmis spp. for energy production, thus negating the need for pre-treatment.