Title page for ETD etd-01232012-163905


Type of Document Dissertation
Author Iqbal, Javed
Author's Email Address jiqbal1@lsu.edu
URN etd-01232012-163905
Title Development of Cost-Effective and Benign Lipid Extraction System for Microalgae
Degree Doctor of Philosophy (Ph.D.)
Department Engineering Science (Interdepartmental Program)
Advisory Committee
Advisor Name Title
Theegala, Chandra Sekhar Committee Chair
Adrian, Donald Dean Committee Member
Portier, Ralph Joseph Committee Member
Kato , Naohiro Dean's Representative
Keywords
  • biofuels
  • biodiesel
  • lipid extraction
  • microwave-assisted extraction
  • biomass
  • microalgae
Date of Defense 2011-12-13
Availability unrestricted
Abstract
A laboratory-made continuous flow lipid extraction system (CFLES) was devised to extract lipids from microalgae Nannochloropsis sp., a potential feedstock for biodiesel fuel, with a focus to assess the workable temperatures and pressures for possible scale-up applications. Using conventional solvents, the CFLES recovered 100% of the lipids recovered with conventional Soxhlet extraction (USEPA method 3540) at moderate 50 psi pressure and 100C temperature; conditions significantly lower than those normally used in pressurized liquid extractions requiring specialized equipment. Approximately 87% of the extracted oil was successfully transesterified into biodiesel fuel. For exploring the solvent potential of biodiesel, CFLES was also tested with 40% methyl-soyate (BD40) as co-solvent with ethanol. Both the solvents are less toxic to health and environment compared to conventional solvents. The system extracted 67% of lipids at 50 psi pressure and 100C temperature. The system also extracted 64% and 65% lipids at pressure/temperature combinations of 50psi/120C and 500psi/120C respectively. Energy efficiency of CFLES was 48.9%. Compared to a lab-scale Soxhlet extraction system (150 mL), the solvents consumption in CFLES was reduced by 80% and 67% for conventional and biodiesel co-solvents, respectively, while extraction time was notably reduced from 8h to 0.25h and 0.67h, respectively. The estimated savings in extraction cost and energy at scaled-up CFLES systems are expected 57% and 60%, respectively, as compared to solvent extraction coupled with mechanical extractor. Based on previous studies, the total cost of microalgae oil production was estimated in the range of $13.73 to $44.60gal-1. The solvent potential of biodiesel was further investigated with the use of methyl-soyate in a closed-vessel microwave-assisted lipid extraction (MAE). Approximately 66%, 78%, and 116% lipids were extracted with BD40 at 80C, 100C, and 120C temperatures, respectively, compared to that extracted with Soxhlet. Maximum efficiency for BD20 (20% methyl-soyate) was 34%. MAE using chloroform/ethanol mixture extracted 32%, 93%, and 108% of lipids at 80C, 100C and 120C, respectively, compared to Soxhlet. Efficiency increased with increased biodiesel proportion in the co-solvent system and increased temperature. To our knowledge, this is the first study to report CFLES and the use of biodiesel as a co-solvent for extraction of biochemicals.
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