title: Highly-efficient enzymatic conversion of crude algal oils into biodiesel.
abstract: Energy-intensive chemical conversion of crude algal oils into biodiesel is a major barrier for cost-effective algal biofuel production. To overcome this problem, we developed an enzyme-based platform for conversion of crude algal oils into fatty acid methyl esters. Crude algal oils were extracted from the oleaginous microalga Nannochloropsis oceanica IMET1 and converted by an immobilized lipase from Candida antarctica. The effects of different acyl acceptors, t-butanol as a co-solvent, oil to t-butanol ratio, oil to methanol ratio, temperature and reaction time on biodiesel conversion efficiency were studied. The conversion efficiency reached 99.1% when the conversion conditions were optimized, i.e., an oil to t-butanol weight ratio of 1:1, an oil to methanol molar ratio of 1:12, and a reaction time of 4h at 25°C. The enzymatic conversion process developed in this study may hold a promise for low energy consumption, low wastewater-discharge biochemical conversion of algal feedstocks into biofuels.
authors.affiliation: Institute of Hydrobiology, Jinan University, Guangzhou 510632, China; Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland Baltimore County, Baltimore, MD 21202, United States.
authors.forename: Yao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland Baltimore County, Baltimore, MD 21202, United States.
authors.forename: Jin
authors.initials: J
authors.lastname: Liu
authors.affiliation: Arizona Center for Algal Technology and Innovation, Arizona State University, Mesa, AZ 85212, United States.
authors.forename: Henri
authors.initials: H
authors.lastname: Gerken
authors.affiliation: Institute of Hydrobiology, Jinan University, Guangzhou 510632, China.
authors.forename: Chengwu
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Hu
authors.affiliation: Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland Baltimore County, Baltimore, MD 21202, United States. Electronic address: yantao@umces.edu.
authors.forename: Yantao
authors.initials: Y
authors.lastname: Li
mesh_terms: D056804:Biofuels; D001709:Biotechnology / Q000379:methods*; D004795:Enzyme Stability; D056890:Eukaryota / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D008049:Lipase / Q000378:metabolism*; D008055:Lipids / Q000096:biosynthesis; D000432:Methanol / Q000378:metabolism; D010578:Petroleum / Q000378:metabolism*; D010944:Plants / Q000378:metabolism; D013696:Temperature; D013997:Time Factors
chemical_list: D056804:Biofuels; D008055:Lipids; D010578:Petroleum; D008049:Lipase; D000432:Methanol
keywords: Crude algal oils; Enzymatic conversion; Fatty acid methyl esters; Lipase; Nannochloropsis oceanica IMET1