Evaluation of growth, nutrient utilization and production of bioproducts by a wastewater-isolated microalga

Abstract

Treatment of wastewater while producing microalgal biomass is receiving ever-increasing attention, particularly in the biofuels arena. In this study, a wastewater chlorophyte isolate, Kirchneriella sp., was tested for its ability to be mass cultivated, utilize nutrients from defined media and wastewater, and produce bioproducts of commercial interest. Growth studies were carried out in various systems at scales up to 60L, with Kirchneriella sp. showing an excellent amenability to being cultured. Biomass concentrations of greater than 1gL(-1) were consistently achieved, nitrogen and phosphorus uptake was rapid, and stable medium-term cultures were maintained. Nitrogen limitation affected biomass yield, fatty acid methyl ester (FAME) yield, and cetane index. In contrast, a low phosphorus condition had no effect. Kirchneriella sp. showed an ability to produce several products of commercial value, including carbohydrate-rich biomass, FAME/biodiesel and the pigments β,β-carotene and lutein.