title: Ultrastructure and composition of the Nannochloropsis gaditana cell wall.
abstract: Marine algae of the genus Nannochloropsis are promising producers of biofuel precursors and nutraceuticals and are also harvested commercially for aquaculture feed. We have used quick-freeze, deep-etch electron microscopy, Fourier transform infrared spectroscopy, and carbohydrate analyses to characterize the architecture of the Nannochloropsis gaditana (strain CCMP 526) cell wall, whose recalcitrance presents a significant barrier to biocommodity extraction. The data indicate a bilayer structure consisting of a cellulosic inner wall (~75% of the mass balance) protected by an outer hydrophobic algaenan layer. Cellulase treatment of walls purified after cell lysis generates highly enriched algaenan preparations without using the harsh chemical treatments typically used in algaenan isolation and characterization. Nannochloropsis algaenan was determined to comprise long, straight-chain, saturated aliphatics with ether cross-links, which closely resembles the cutan of vascular plants. Chemical identification of >85% of the isolated cell wall mass is detailed, and genome analysis is used to identify candidate biosynthetic enzymes.
authors.affiliation: Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Scholz
authors.affiliation: Department of Biology, Washington University, St. Louis, Missouri, USA.
authors.forename: Taylor L
authors.initials: TL
authors.lastname: Weiss
authors.affiliation: Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado, USA.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Jinkerson
authors.affiliation: CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and BioEnergy Genome Center, Qindao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Jing
authors.affiliation: Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA.
authors.forename: Robyn
authors.initials: R
authors.lastname: Roth
authors.affiliation: Department of Biology, Washington University, St. Louis, Missouri, USA.
authors.forename: Ursula
authors.initials: U
authors.lastname: Goodenough
authors.affiliation: Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado, USA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Posewitz
authors.affiliation: Arizona Center for Algal Technology and Innovation, Arizona State University, Mesa, Arizona, USA hgerken@asu.edu.
authors.forename: Henri G
authors.initials: HG
authors.lastname: Gerken
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D059001:Aquatic Organisms / Q000648:ultrastructure; D001483:Base Sequence; D002473:Cell Wall / Q000648:ultrastructure*; D008854:Microscopy, Electron; D017422:Sequence Analysis, DNA; D017550:Spectroscopy, Fourier Transform Infrared; D058009:Stramenopiles / Q000201:enzymology / Q000235:genetics / Q000648:ultrastructure*
chemical_list: D000596:Amino Acids