A sustainable mixotrophic microalgae cultivation from dairy wastes for carbon credit, bioremediation and lucrative biofuels

Globally, high CO₂-emitting dairy industry obligated to treat waste and improve its carbon-footprints. Mixotrophic cultivation strategy (MCS) of microalgae enables to treat dairy wastes and mitigate CO₂ for sustainable dairy economy. This study developed a biochemical process for organic whey with minimum dilution to avoid environmental burden. To make whey suitable for algae cultivation, it was pre-treated to remove polymers, unwanted solid fractions, opacity, and organic and inorganic overloads via acid hydrolysis, chemical flocculation and struvite formations with lowest dilution possible. 40% pretreated whey was most productive for biomass and lipid fractions respectively 4.54 and 1.80 gl⁻¹ with daily productivities 0.50 and 0.20 gl^-1d^-1, however 25% to reach adequate treatment. Overall, biochemical treatment was effective to remove respectively 99.7 and 91–100% of organic and inorganic pollutants, however algal treatment alone exhibited maximum 92.6 and 48.5–98.4% removals from both treatment ratios which is promising finding of this work.