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Hydrothermal processing of biomass from invasive
W. James Catallo
, Todd F. Shupe
, Thomas L. Eberhardt
Laboratory for Ecological Chemistry, Comparative Biomedical Sciences Department, Louisiana State University, Baton Rouge, LA 70803, USA
School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA
USDA Forest Service, Southern Research Station, Pineville, LA 71360, USA
Received 19 September 2006
Received in revised form
17 July 2007
Accepted 25 July 2007
Available online 4 September 2007
Hydrothermal reaction systems
The purpose of this study was to examine the hydrothermal (HT) treatment of three
invasive aquatic plants (i.e., Lemna sp., Hydrilla sp., and Eichhornia sp.) with respect to the
generation of semi-volatile hydrocarbon product mixtures and biomass volume reduction.
Identical HT treatments yielded similar semi-volatile product mixtures for Hydrilla sp. and
Eichhornia sp. versus a signiﬁcantly different mixture for Lemna sp. Pre-treatment
(i.e., control) extracts of the plant substrates showed no semi-volatile hydrocarbons.
Post-HT treatment product mixtures were comprised of complex mixtures of compounds
including branched and unbranched alkanes and alkenes as well as light aromatics
including substituted benzenes and phenols. All three plant HT product mixtures were
dominated by phenol, C
alkyl phenols, and oxygenated cycloalkenes. Lemna sp. products
showed much more diverse distributions of C
alkyl benzenes, alkyl indanes, and alkyl
naphthalenes at higher relative levels. Other products from the Lemna sp. HT treatment
phenols, and alkyl indole and indanol compounds. Results of wet chemical
analyses showed that a major difference between Lemna sp. and the other two plants was
signiﬁcantly higher extractives levels in the former. It was found that this fraction
accounted for much of the complexity in HT product mixture of the Lemna sp. biomass. For
all HT treatments the substrate mass was reduced by 95% or more.
& 2007 Published by Elsevier Ltd.
In recent years, the authors have documented the transforma-
tion of under-utilized biomass (WB) into gas-phase and semi-
volatile hydrocarbon mixtures in hydrothermal (HT) reaction
systems. HT refers to near- and supercritical water systems
(e.g., 300–700 1C, 20–50MPa) under anoxic (reducing) conditions.
HT treatments of all types of biomass (e.g., protein, cellulose,
chitin, starch, DNA, bacteria cells, yeast cells, diatoms, decom-
missioned preservative-treated wood, grass, invasive and
noxious terrestrial vegetation, and municipal sewage slurry)
have resulted in transformation of the biomolecules to
mixtures of gas- and liquid-phase aromatic and aliphatic
chemicals [1–4]. HT transformation data in these studies were
generated under simple reaction conditions (i.e., the substrates
were treated in heated water under pressure with no added
reactants or catalysts) with the intention of (1) estimating gas-
phase and semi-volatile hydrocarbon yields of WB resources,
(2) identifying the most abundant hydrocarbons generated in
this process, and (3) relating where possible the products to
speciﬁc precursors in the WB.
Currently, there are no data in the public domain on
products resulting from HT treatment of vascular aquatic
plants, particularly those which pose ecological problems
(i.e., invasive or noxious nature). In many temperate aquatic
ecosystems, non-woody aquatic pest vegetation can become
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Corresponding author. Tel.: +1 225 578 6432; fax: +1 225 5784251.
E-mail address: email@example.com (T.F. Shupe).
BIOMASS AND BIOENERGY
32 (2008) 140– 145