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DOI 10.2172/782629
Title Trees Containing Built-In Pulping Catalysts - Final Report - 08/18/1997 - 08/18/2000
Creator/Author Pullman, G. ; Dimmel, D. ; Peter, G.
Publication Date2000 Aug 18
OSTI IdentifierOSTI ID: 782629
Report Number(s)DOE/ID/13538
DOE Contract NumberFC07-97ID13538
DOI10.2172/782629
Other Number(s)TRN: AH200126%%215
Resource TypeTechnical Report
Resource RelationOther Information: PBD: 18 Aug 2000
CoverageFinal
Research OrgInstitute of Paper Science and Technology, Atlanta, GA (US)
Sponsoring OrgUSDOE Office of Environmental Management (EM) (US)
Subject59 BASIC BIOLOGICAL SCIENCES; 54 ENVIRONMENTAL SCIENCES; AMINO ACIDS; CATALYSTS; ENZYME ACTIVITY; GENETIC ENGINEERING; PLANT CELLS; PLANT STEMS; PLANT TISSUES; SHIKIMIC ACID; TREES
Related SubjectANTHRAQUINONE; WOOD PULPING; GENETIC ENGINEERING; ISOCHORISMATE SYNTHASE; PLANT TISSUE
Description/AbstractSeveral hardwood and softwood trees were analyzed for the presence of anthraquinone-type molecules. Low levels of anthraquinone (AQ) and anthrone components were detected using gas chromatography-mass spectroscopy and sensitive selected-ion monitoring techniques. Ten out of seventeen hardwood samples examined contained AQ-type components; however, the levels were typically below {approximately}6 ppm. No AQs were observed in the few softwood samples that were examined. The AQs were more concentrated in the heartwood of teak than in the sapwood. The delignification of pine was enhanced by the addition of teak chips ({approximately}0.7% AQ-equivalence content) to the cook, suggesting that endogenous AQs can be released from wood during pulping and can catalyze delignification reactions. Eastern cottonwood contained AQ, methyl AQ, and dimethyl AQ, all useful for wood pulping. This is the first time unsubstituted AQ has been observed in wood extracts. Due to the presence of these pulping catalysts, rapid growth rates in plantation settings, and the ease of genetic transformation, eastern cottonwood is a suitable candidate for genetic engineering studies to enhance AQ content. To achieve effective catalytic pulping activity, poplar and cottonwood, respectively, require {approximately}100 and 1000 times more for pulping catalysts. A strategy to increase AQ concentration in natural wood was developed and is currently being tested. This strategy involves ''turning up'' isochorismate synthase (ICS) through genetic engineering. Isochorismate synthase is the first enzyme in the AQ pathway branching from the shikimic acid pathway. In general, the level of enzyme activity at the first branch point or committed step controls the flux through a biosynthetic pathway. To test if the level of ICS regulates AQ biosynthesis in plant tissues, we proposed to over-express this synthase in plant cells. A partial cDNA encoding a putative ICS was available from the random cDNA sequencing project carried out with Arabidopsis thaliana. We used this putative plant ICS gene fragment to isolate and sequence a full-length ICS cDNA from Arabidopsis thaliana. The putative full-length cDNA encodes for a 569 amino acid protein of {approximately}62kDa. This sequence represents the first full-length ICS cDNA isolated from a plant. When inserted into E. coli, our isolated cDNA over-expressed ICS protein in the insoluble inclusion bodies. A plant expression vector containing the ICS cDNA, NP II for selection on the antibiotic kanamycin, and duplicated 35S-cauliflower mosaic virus promoter were inserted into Agrobacterium tumefaciens strain GV3101. Transformation experiments for insertion of these foreign genes into Populus deltoides 'C175' resulted in eight lines able to regenerate shoots and grow roots in the presence of kanamycin. Plants from these eight lines have acclimated to growth in sterile soil and will be moved to a greenhouse environment in spring 2001. Non rooted shoots from each line are currently being multiplied by shoot culture. When enough shoot tissue and/or greenhouse plant stem tissue is available, AQ analysis will be done and compared with non transformed control tissue.
Country of PublicationUnited States
LanguageEnglish
FormatMedium: ED; Size: vp.
Availability OSTI as DE00782629
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System Entry Date2008 Feb 05
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