Nitrogen and phosphorus removal coupled to CO2 fixation by two green microalgae, Chlorella sp. and Quadrigula sp., native to the coast of Chiapas, Mexico

Microalgae remove nitrogen and phosphorus from water for their growth and biomass production, wich has several biotechnological applications. This study evaluated the growth, NO3−, NO2−, NH4+, urea, PO43− and total nitrogen removal capacity, as well as the biomass production and the CO2 fixation of two new microalgae isolates, Chlorella sp. and Quadrigula sp., from the coast of Chiapas, México. Chlorella sp. had a higher specific growth rate (0.74/day) and a shorter doubling time (0.92 days) than Quadrigula sp. Removal per unit volume (mg/L) of NO3−, NH4+ and total nitrogen by Chlorella sp. was higher (26.88%, 10.58% and 16.63%, respectively) than removal by Quadrigula sp. On the other hand, daily removal (mg/L/d) of NO3−; NH4+; NO2−; urea and total nitrogen by Chlorella sp. was also higher (88%, 33%, 89%,15% and 50%, respectively) than daily removal by Quadrigula sp. The biomass productivity (mg/L/d) and the CO2 fixation rate (mg/L/d) were similar among both microalgae. The results of this study suggest that Chlorella sp. and Quadrigula sp. have potential for nutrient removal, biomass production and CO2 fixation.