Cultivation of Neochloris oleoabundans in bubble column photobioreactor with or without localized deoxygenation

This study evaluated long-term non-sterile cultivation of freshwater green alga Neochloris oleoabundans in a 15-liter bubble column photobioreactor (BCPBR) and the effects of a membrane-based localized oxygen remover (LOR) on deoxygenation, cell growth, and lipid production of N. oleoabundans. Batch and continuous cultivations were carried out under non-sterile conditions for 53 days with no detectable protozoa or other biological contaminants, indicating successful long-term contamination-free cultivation. The results show that the BCPBR equipped with LOR (BCPBR-LOR) has enhanced deoxygenation efficiency and were able to maintain dissolved oxygen at a level of around 120% air saturation, which was 32% lower than that of the conventional BCPBR, which had no LOR. While similar biomass concentration and productivity were obtained in both systems, significantly higher lipid cell content and lipid productivity of microalgae were obtained in the latter, which was attributed to the low dO2 in culture due to enhanced deoxygenation efficiency of BCPBR-LOR.