Abstract

Microalgae lipids could be a good alternative feedstock for liquid fuel, but complex processing steps with significant energy demands present roadblocks. Combining biomass harvesting and lipid recovery into one simple step can lower complexity and energy costs. This study evaluated the use of C12-C16 cationic surfactants in this synergistic manner. First, we determined that a dose as low as 0.45 mM of C16-alkyl-chain cationic surfactant (hexadecyltrimethylammonium, CTAB) led to >85% biomass-harvesting rate for Chlorella biomass, and good harvest was correlated to a slightly positive zeta potential. Second, the cationic surfactants disrupted cell structures (detected by transmission electron microscopy) and led to lipid recovery (measured as fatty acid methyl esters, FAME) as high as 90% using nontoxic ethyl acetate (EA) as the solvent and without altering the FAME distribution; for context, EA was able to extract less than 1% of FAME from control (not surfactant-treated) Chlorella. Disruption and high FAME yield were associated with surfactants' critical micelle concentration (CMC): a lower CMC required a lower concentration of surfactant to disrupt the cells. The synergistic benefits of cationic surfactants can be attained by maintaining a slightly positive zeta potential for effective flocculation and adding the minimum concentration of surfactant needed for cell disruption.

Original languageEnglish (US)
Pages (from-to)752-757
Number of pages6
JournalACS Sustainable Chemistry and Engineering
Volume5
Issue number1
DOIs
StatePublished - Jan 3 2017

Fingerprint

Cationic surfactants
Flocculation
flocculation
Fatty acids
Surface-Active Agents
Lipids
surfactant
Esters
Biomass
Surface active agents
Fatty Acids
lipid
Critical micelle concentration
biomass
Zeta potential
ester
fatty acid
Recovery
Liquid fuels
Feedstocks

Keywords

  • Cationic surfactant
  • Harvesting
  • Lipid extraction
  • Microalga biomass
  • Synergistic integration

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment

Cite this

Synergistic Integration of C12-C16 Cationic Surfactants for Flocculation and Lipid Extraction from Chlorella Biomass. / Lai, Yenjung Sean; Zhou, Yun; Martarella, Rebecca; Wang, Zhaocheng; Rittmann, Bruce.

In: ACS Sustainable Chemistry and Engineering, Vol. 5, No. 1, 03.01.2017, p. 752-757.

Research output: Contribution to journalArticle

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