Enhanced Microalgae Growth for Biodiesel Production and Nutrients Removal in Raw Swine Wastewater by Carbon Sources Supplementation

Abstract: In the present work, effect of two carbon sources, namely, sodium bicarbonate and sodium acetate, on the growth of Spirulina platensis, raw swine wastewater (RSW) nutrients removal, and lipid production efficiency was thoroughly investigated. Experimental results showed that maximum biomass concentration and total nitrogen (TN), total phosphorous (TP), and ammonium removal percentage of 1.70 g L⁻¹, 91.24%, 87.44%, 100% were achieved, respectively, when sodium bicarbonate was supplemented to the RSW, which were significantly (p < 0.05) higher than that of the control. With regard to sodium acetate as extra carbon source, maximum biomass concentration and TN, TP, and ammonium removal percentage reached 2.18 g L⁻¹, 85.72%, 87.02%, and 100%, respectively, which were notably enhanced compared to that of the control. Furthermore, saturated fatty acids and unsaturated fatty acids content in the obtained biomass ranged from 68.01–69.44% to 30.56–31.99%, respectively, and hexadecanoic acid, palmitoleic acid, octadecenoic acid and linoleic acid were found to be the major fatty acid components in the algal lipids. Thus, sodium bicarbonate and sodium acetate supplementation to RSW are technically feasible strategies to enhance Spirulina platensis growth for simultaneously nutrients removal and biodiesel production. Graphic Abstract: [Figure not available: see fulltext.].