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Carbon bio-fixation, effect of physicochemical factors and carbon supply strategies by Nannochloropsis sp. using flue gas and fertilizer

Banerjee, Avik, Guria, Chandan, Maiti, Subodh Kumar, Banerjee, Chiranjib, Shukla, Pratyoosh
Biomass and bioenergy 2019 v.125 pp. 95-104
Nannochloropsis, algorithms, biomass, carbon, carbon dioxide, carbon nitrogen ratio, carbon sequestration, decision making, flue gas, light intensity, lipids, metabolism, microalgae, mineral fertilizers, nutrients, response surface methodology, salinity
As atmospheric CO2 is rising alarmingly, focused research on microalgal based bio-mitigation of CO2 has become relevant. With the aim of single-objective maximization, response surface methodology (RSM) study was employed through central composite design (CCD) for the phototropic cultivation of Nannochloropsis sp. using Flue gas and synthetic fertilizer (NPK-10:26:26). Influence of crucial external factors such as light, salinity, carbon content and nutrients were investigated along with their interactions on three objectives such as Biomass, Lipid, and carbon bio-fixation rate. Using fertilizer assisted RSM optimized media, an enhancement of 43, 31, and 79% was observed in three responses over standard f/2 medium. Variation in carbon content (32%) and C/N ratio (100%) was observed, that validated diversion of metabolism under stress. The multi-objective optimization was carried out by genetic algorithm. A carbon supply strategy was employed that enhances biomass growth. Carbon sequestration was calculated first time precisely. Light intensity was concluded as a dominant external inducer to carbon-sequestration and lipid accumulation. Carbon sequestration rate was revealed to enhance in conditions that favor both good growths and induce stress. Single and multi-objective optimization data in this study can help in commercial decision making required in large scale-cultivations for biotechnological gains.