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Poster Presentation 3-08
The Effect of Modified Pretreatment Parameters on Delignification in the Bioconversion Process
I.F. Cullis, J.N. Saddler and S.D. Mansfield
Forest Products Biotechnology, Department of Wood Science University of British Columbia, Vancouver, B.C. V6T 1Z4 Canada
Telephone: (604) 822-0196; Fax: (604) 822-9104; E-mail: shawnman@interchange.ubc.ca
Modified pre-treatment parameters were investigated in attempts to improve the efficacy of the delignification steps in the bioconversion process, which consequently is one of the most costly process variables. Three different parameters were manipulated, including: chip size, post steam explosion particle size, and moisture content. All variables are believed to significantly affect the severity of steam pretreatment of softwood wood chips.
It was apparent that a substantial improvement in delignification efficiency with a hot alkaline peroxide step was attainable by increasing chip size. Subsequently, it was shown that by refining the residual solid residue with a Sproat-Waldron mechanical refiner post steam explosion an additional 5 % reduction in the lignin content of the substrate was achievable. Furthermore, it was shown that chips with higher initial moisture contents (30 %), responded favourably to steam explosion at medium severity, and demonstrated improved delignification efficiency, reducing the lignin content by an additional 1.5 %.
Therefore, it is apparent that cost saving in delignification can be achieved by use of the optimum pretreatment chip conditions, which appear to be larger chips with a high moisture content, followed by post steam explosion refining.
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