Evaluation of chlorella sorokiniana biomass recovery by using different chemical-based flocculants

Funding Information: The authors gratefully acknowledge the Brazilian research funding agencies CNPq (National Council for Scientific and Technological Development), FUNDECT (Mato Grosso do Sul State Foundation for the Support and Development of Education, Science and Technology) and CAPES (Federal Agency for the Support and Improvement of Higher Education) for their financial support. Publisher Copyright: © Baqiyatallah University of Medical Sciences. All rights reserved.Introduction: The nature and the concentration of the chemical agents responsible for cell flocculation are the bottlenecks for microalgae recovery. The aim of the present study was to evaluate different chemical-based flocculants for Chlorella sorokiniana flocculation. Materials and Methods: The biomass recovery efficiency was evaluated by comparing self-flocculation and flocculation with the ferric chloride, sodium hydroxide, aluminum sulfate, and zinc sulfate. After identifying the best flocculating agent, its concentration was varied to determine the optimal condition by rapid agitation followed by sedimentation (0.25 to 1 g/L). Results: Zinc sulfate was unsuitable for this strain due to an efficiency lower than 40%. Self-flocculation and sodium hydroxide were fairly efficient (48.65% and 58.06%, respectively). Aluminum sulfate produced moderate results (56.27%), but flocculation took a long time to become efficient. Ferric chloride showed the best potential for flocculation, and in the analysis of different concentrations (0.25 to 1 g/L) showed to be fast and efficient (nearly 80% of biomass recovery in 10 min) at a concentration of 0.75 g/L. Conclusions: All the flocculants tested in this study can be utilized for biomass recovery, except for the zinc sulfate. The procedure was efficient, inexpensive, and contaminant-free for the recovery of C. sorokiniana biomass.Introduction: The nature and the concentration of the chemical agents responsible for cell flocculation are the bottlenecks for microalgae recovery. The aim of the present study was to evaluate different chemical-based flocculants for Chlorella sorokiniana flocculation. Materials and Methods: The biomass recovery efficiency was evaluated by comparing self-flocculation and flocculation with the ferric chloride, sodium hydroxide, aluminum sulfate, and zinc sulfate. After identifying the best flocculating agent, its concentration was varied to determine the optimal condition by rapid agitation followed by sedimentation (0.25 to 1 g/L). Results: Zinc sulfate was unsuitable for this strain due to an efficiency lower than 40%. Self-flocculation and sodium hydroxide were fairly efficient (48.65% and 58.06%, respectively). Aluminum sulfate produced moderate results (56.27%), but flocculation took a long time to become efficient. Ferric chloride showed the best potential for flocculation, and in the analysis of different concentrat ions (0.25 to 1 g/L) showed to be fast and efficient (nearly 80% of biomass recovery in 10 min) at a concentration of 0.75 g/L. Conclusions: All the flocculants tested in this study can be utilized for biomass recovery, except for the zinc sulfate. The procedure was efficient, inexpensive, and contaminant-free for the recovery of C. sorokiniana biomass.Peer reviewe

Porphyridium cruentum Grown in Ultra-Filtered Swine Wastewater and Its Effects on Microalgae Growth Productivity and Fatty Acid Composition

Microalgae have been extensively tested for their ability to create bio-based fuels. Microalgae have also been explored as an alternative wastewater treatment solution due to their significant uptake of nitrogen and phosphorus, as well as their ability to grow in different water types. Recently, there has been significant interest in combining these two characteristics to create economic and environmentally friendly biofuel using wastewater. This study examined the growth and lipid production of the microalgae Porphyridium (P.) cruentum grown in swine wastewater (ultra-filtered and raw) as compared with control media (L−1, modified f/2) at two different salt concentrations (seawater and saltwater). The cultivation of P. cruentum in the treated swine wastewater media (seawater = 5.18 ± 2.3 mgL−1day−1, saltwater = 3.32 ± 1.93 mgL−1day−1) resulted in a statistically similar biomass productivity compared to the control medium (seawater = 2.61 ± 2.47 mgL−1day−1, saltwater = 6.53 ± 0.81 mgL−1day−1) at the corresponding salt concentration. Furthermore, no major differences between the fatty acid compositions of microalgae in the treated swine wastewater medium and the control medium were observed. For all conditions, saturated acids were present in the highest amounts (≥67%), followed by polyunsaturated (≤22%) and finally monounsaturated (≤12%). This is the first study to find that P. cruentum could be used to remediate wastewater and then be turned into fuel by using swine wastewater with a similar productivity to the microalgae grown in control media