The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform

Pierre Metzger - One of the best experts on this subject based on the ideXlab platform.

Marie Noelle Rager - One of the best experts on this subject based on the ideXlab platform.

Claude Largeau - One of the best experts on this subject based on the ideXlab platform.

  • c31 c34 methylated squalenes from a bolivian strain of Botryococcus braunii
    Phytochemistry, 2004
    Co-Authors: Etienne Achitouv, Marie Noelle Rager, Pierre Metzger, Claude Largeau
    Abstract:

    Three new triterpenes, synthesized by a Bolivian strain of the green microalga Botryococcus braunii, were isolated and their chemical structures determined by 1D and 2D NMR, and mass spectrometry. These compounds are tri-, di-, and mono-methylsqualenes, co-occurring with the previously identified tetramethylsqualene and some C(30)-C(32) botryococcenes. In this strain, methylated squalenes constitute up to 24% of the total hydrocarbons and 4.5% of the dry biomass. The results of a pulse-chase experiment with L-[Me-(13)C] methionine provide evidence for the origin of these compounds via methylation of squalene at positions 3, 7, 18 and 22.

  • Lycopanerols I-L, four new tetraterpenoid ethers from Botryococcus braunii.
    Journal of Natural Products, 2003
    Co-Authors: Pierre Metzger, Marie Noelle Rager, Nicole Sellier, Claude Largeau
    Abstract:

    Four new tetraterpenoid ethers, lycopanerols I-L (5-8), were isolated from a culture of a strain of the green microalga Botryococcus braunii (L race). The structures were determined by means of spectral analyses and chemical degradation. The relative stereochemistry of these ethers was established by ROESY NMR. A biogenetic relationship is proposed between lycopanerols and lycopadiene (1), the acyclic diunsaturated tetraterpene hydrocarbon synthesized by the alga.

  • polymethylsqualanes from Botryococcus braunii in lacustrine sediments and crude oils
    Organic Geochemistry, 2002
    Co-Authors: Claude Largeau, Pierre Metzger, Roger E. Summons, Andrew P Murray, Janet Hope
    Abstract:

    Abstract A novel hydrocarbon 3,7,18,22-tetramethylsqualane has been identified in extracts from the Maniguin-2 well on Maniguin Island, Philippines, the Duri oil from Sumatra, Indonesia and the Maoming Oil Shale from China. A related hydrocarbon, tentatively assigned the structure 3,7,11,14-tetramethylsqualane, occurs in the Maniguin samples. Like C34 botryococcane, the tetramethylsqualanes are unusually enriched in 13C compared to co-occuring n-alkanes and C16–20 acyclic isoprenoids. Polymethylsqualanes extend the range of distinctive hydrocarbons produced by Botryococcus braunii and its fossil counterparts.

  • Botryolins A and B, two tetramethylsqualene triethers from the green microalga Botryococcus braunii
    Phytochemistry, 2002
    Co-Authors: Pierre Metzger, Marie Noelle Rager, Claude Largeau
    Abstract:

    Two new triterpenoid polyethers with a tetramethylsqualene carbon skeleton, botryolins A and B, have been isolated from the green microalga Botryococcus braunii. Their structures were determined by means of spectral analyses including 2D NMR.

Makoto M Watanabe - One of the best experts on this subject based on the ideXlab platform.

  • Hexagonal Disk Structures Obtained during Carbonization of Botryococcus braunii Residues
    Journal of Materials Science and Chemical Engineering, 2017
    Co-Authors: Aohan Wang, Makoto M Watanabe, Mikihide Demura, Hiromasa Goto
    Abstract:

    In this study, we report a two-dimensional (2D) hexagonal disk obtained by carbonization of Botryococcus braunii (B. braunii) residues. Carbonization at 700℃followed by naturally cooling down to room temperature under a non-inert gas flow atmosphere affords to yield this unique structure. The 2D hexagonal disks consist of more than 52% carbon and more than 25% oxygen. Slight amount of Fe, silicon and magnesium would be the trigger of the formation of hexagonal structure. Treatment of biomass residue is a challenge in the near future accompanied by the achievement of new energy technology in the industrial level. This research points out that efficient use of discharged biomass residue could create a new avenue for material science. The morphology of obtained crystals carbonized in different conditions, especially with the existence of argon flow, was also investigated.

  • catalytic gasification of oil extracted residue biomass of Botryococcus braunii
    Bioresource Technology, 2015
    Co-Authors: Hideo Watanabe, Yoshinao Nakagawa, Keiichi Tomishige, Makoto M Watanabe
    Abstract:

    Catalytic gasification of the oil-extracted residue biomass of Botryococcus braunii was demonstrated in a laboratory-scale continuous feeding dual bed reactor. Steam gasification at 1023 K over Ni-Fe/Mg/Al catalyst can completely reform tar derived from pyrolysis of the residue biomass into C1 gases and hydrogen, and has achieved 91%-C conversion to gaseous product (CO+CO2+CH4). Composition of product gas has higher contents of CO and H2 with their ratio (H2/CO) of around 2.4 which is slightly H2-rich syngas. Maximum hydrogen yield of 74.7 mmol g-biomass(-1) obtained in this work is much higher than that from gasification of other algal biomass reported in literature. The residue biomass of B. braunii can be a superior renewable source of syngas or hydrogen.

  • A novel alphaproteobacterial ectosymbiont promotes the growth of the hydrocarbon-rich green alga Botryococcus braunii
    Scientific Reports, 2015
    Co-Authors: Yuuhiko Tanabe, Masaki Yoshida, Yusuke Okazaki, Takashi Shiratori, Ken-ichiro Ishida, Hiroshi Matsuura, Shin-ichi Nakano, Makoto M Watanabe
    Abstract:

    Botryococcus braunii is a colony-forming green alga that accumulates large amounts of liquid hydrocarbons within the colony. The utilization of B. braunii for biofuel production is however hindered by its low biomass productivity. Here we describe a novel bacterial ectosymbiont (BOTRYCO-2) that confers higher biomass productivity to B. braunii . 16S rDNA analysis indicated that the sequence of BOTRYCO-2 shows low similarity (

  • Isolation of herbicide-resistant mutants of Botryococcus braunii.
    Bioresource Technology, 2012
    Co-Authors: Motohide Ioki, Masahiro Ohkoshi, Nobuyoshi Nakajima, Yuka Nakahira-yanaka, Makoto M Watanabe
    Abstract:

    Aiming at herbicide-assisted cultivation of Botryococcus braunii for prevention of algal contamination, herbicide-tolerant mutant lines of B. braunii were established for two widely used herbicides, methyl viologen and glufosinate. Some established mutant lines exhibited vigorous oil production and growth in herbicide-containing media. Because the two herbicides were effective in controlling the growth of the algal competitors of B. braunii, these mutants can be directly used in industrial attempts for cost-effective oil production in herbicide-assisted non-axenic systems. This is the first report of mutagenesis of B. braunii.

  • effects of carbon source on growth and morphology of Botryococcus braunii
    Journal of Applied Phycology, 2011
    Co-Authors: Takako Tanoi, Masanobu Kawachi, Makoto M Watanabe
    Abstract:

    The green colonial alga Botryococcus braunii is characterized by the ability to produce and accumulate large amounts of hydrocarbons. We isolated and established an axenic clonal strain of B. braunii B70 and investigated the effects of organic carbon sources, including glucose, mannose, fructose, galactose, or acetate, on growth under light and dark conditions. This algal strain had the capacity to grow photo-, mixo-, or heterotrophically. Growth was promoted substantially following exposure of the algae to glucose or mannose under light exposure. Cells could grow under continuous darkness with glucose or mannose. In the presence of glucose under light or dark conditions, cell and colony size, and the intracellular granules containing oil, were markedly larger than those cultured without glucose.

Olaf Kruse - One of the best experts on this subject based on the ideXlab platform.

  • Metabolic survey of Botryococcus braunii: Impact of the physiological state on product formation
    PLOS ONE, 2018
    Co-Authors: Olga Blifernez-klassen, Jörn Kalinowski, Swapnil M. Chaudhari, Viktor Klassen, Robin Wördenweber, Tim Steffens, Dominik Cholewa, Karsten Niehaus, Olaf Kruse
    Abstract:

    The microalga Botryococcus braunii is widely regarded as a potential renewable and sustainable source for industrial applications because of its capability to produce large amounts of metabolically expensive (exo-) polysaccharides and lipids, notably hydrocarbons. A comprehensive and systematic metabolic characterization of the Botryococcus braunii race A strain CCAP 807/2 was conducted within the present study, including the detailed analysis of growth-associated and physiological parameters. In addition, the intracellular metabolome was profiled for the first time and showed growth- and product-specific fluctuations in response to the different availability of medium resources during the cultivation course. Among the identified metabolites, a constant expression of raffinose was observed for the first time under standard conditions, which has until now only been described for higher plants. Overall, the multilayered analysis during the cultivation of strain CCAP 807/2 allowed the differentiation of four distinct physiological growth phases and revealed differences in the production profiles and content of liquid hydrocarbons and carbohydrates with up to 84% of organic dry weight (oDW). In the process, an enhanced production of carbohydrates with up to 63% of oDW (1.36±0.03 g L-1) could be observed during the late linear growth phase, whereas the highest accumulation of extracellular hydrocarbons with up to 24% of oDW (0.66±0.12 g L-1) occurred mainly during the stationary growth phase. Altogether, the knowledge obtained is potentially useful for the general understanding of the overall physiology of Botryococcus braunii and provide important insights into the growth behavior and product formation of this microalga, and is thus relevant for large scale biofuel production and industrial applications.

  • Complete Chloroplast and Mitochondrial Genome Sequences of the Hydrocarbon Oil-Producing Green Microalga Botryococcus braunii Race B (Showa)
    Genome Announcements, 2016
    Co-Authors: Olga Blifernez-klassen, Daniel Wibberg, Anika Winkler, Jochen Blom, Alexander Goesmann, Jörn Kalinowski, Olaf Kruse
    Abstract:

    ABSTRACT The green alga Botryococcus braunii is capable of the production and excretion of high quantities of long-chain hydrocarbons and exopolysaccharides. In this study, we present the complete plastid and mitochondrial genomes of the hydrocarbon-producing microalga Botryococcus braunii race B (Showa), with a total length of 156,498 and 129,356 bp, respectively.