Enhanced lipid and biodiesel production from glucose-fed activated sludge: Kinetics and microbial community analysis

Authors

  • Andro H. Mondala,

    1. Renewable Fuels and Chemicals Laboratory, Dave C. Swalm School of Chemical Engineering, Mississippi State University, MS 39762
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  • Rafael Hernandez,

    Corresponding author
    1. Renewable Fuels and Chemicals Laboratory, Dave C. Swalm School of Chemical Engineering, Mississippi State University, MS 39762
    • Renewable Fuels and Chemicals Laboratory, Dave C. Swalm School of Chemical Engineering, Mississippi State University, MS 39762
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  • Todd French,

    Corresponding author
    1. Renewable Fuels and Chemicals Laboratory, Dave C. Swalm School of Chemical Engineering, Mississippi State University, MS 39762
    • Renewable Fuels and Chemicals Laboratory, Dave C. Swalm School of Chemical Engineering, Mississippi State University, MS 39762
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  • Linda McFarland,

    1. Renewable Fuels and Chemicals Laboratory, Dave C. Swalm School of Chemical Engineering, Mississippi State University, MS 39762
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  • Jorge W. Santo Domingo,

    1. U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, Cincinnati, OH 45268
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  • Mark Meckes,

    1. U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, Cincinnati, OH 45268
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  • Hodon Ryu,

    1. U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, Cincinnati, OH 45268
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  • Brandon Iker

    1. U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, Cincinnati, OH 45268
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Abstract

An innovative approach to increase biofuel feedstock lipid yields from municipal sewage sludge via manipulation of carbon-to-nitrogen (C:N) ratio and glucose loading in activated sludge bioreactors was investigated. Sludge lipid and fatty acid methyl ester (biodiesel) yields (% cell dry weight, CDW) were enhanced via cultivation in activated sludge bioreactors operated at high initial C:N ratio (≥40:1) and glucose loading (≥40 g L−1). Under C:N 70, 60 g L−1 glucose loading, a maximum of 17.5 ± 3.9 and 10.2 ± 2.0% CDW lipid and biodiesel yields, respectively, were achieved after 7 d of cultivation. The cultured sludge lipids contained mostly C16[BOND]C18 fatty acids, with oleic acid consistently accounting for 40–50% of the total fatty acids. Microbial composition in activated sludge exposed to C:N 70 shifted toward specific gammaproteobacteria, suggesting their relevance in lipid production in wastewater microbiota and potential value in biofuel synthesis applications. © 2011 American Institute of Chemical Engineers AIChE J, 2012

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