Potential of Monoraphidium minutum for carbon sequestration and lipid production in response to varying growth mode

Mixotrophic growth at flask level and, autotrophic–mixotrophic and autotrophic growth in photobioreactor by utilizing CO2/air/flue gas were checked for the isolated strain of Monoraphidium minutum from polluted habitat. Our study confirmed that it is a saturated fatty acid rich (30.92–68.94%) microalga with lower degree of unsaturation oil quality (42.06–103.99) making it potential biodiesel producing candidate. It showed encouraging biomass productivity (80.3–303.8 mgl−1 day−1) with higher total lipid (22.80–46.54%) under optimum glucose, fructose, microalgal biodiesel waste residue and sodium acetate fed mixotrophic conditions. The pH control by intermittent CO2, continuous illumination with 30% flue gas, and utilization of biodiesel glycerin were effective schemes to ameliorate either biomass productivity or % lipids or both of these parameters at photobioreactor scale (7.5 L working volume). The modulation of environmental variables (pH control, CO2 and organic substrates concentration) could augment % saturated fatty acids, such as C16:0.