Sunday, April 29, 2007

Production of a Phanerochaete chrysosporium ligninase enzyme within feedstock biomass might reduce the needs for expensive pretreatment processes

Mariam Sticklen1, C. Mei2, C. Ransom1, R. Sabzikar1, and Y. Zhai1. (1) Crop and Soil Sciences, MSU, 362 PSSB, MSU, East Lansing, MI 48824, (2) CSS, MSU, 361 PSSB, East Lansing, MI 48824

At present, pretreatment processes are performed to disrupt feedstock biomass and to remove lignin so there would be easy access of the hydrolytic enzymes to the cellulose of the matter. The operation costs of ammonia, acid and/or heat pretreatment of feedstock biomass used to remove lignin and allow the access of cellulase enzymes to the cellulose of biomass is $1.10 to $2.25/gallon of ethanol (Eggeman, 2005). These costs do not include the costs of production of hydrolytic enzymes, fermentation of sugars into alcohol fuels, feedstock production, transportation or storage. Therefore, lignin is considered the major blocking agent in conversion of biomass into alcohol fuels which is very costly to overcome (Sticklen, 2006a). We have developed a series of gene constructs and genetically engineered tobacco and corn using the white rot filamentous Phanerochaete chrysosporium ligninase (de Boer et al., 1988) transgene. To date, our results indicate that this gene has been expressed in crops. Work is in progress to confirm the biological activity of this gene in plants, and to test whether the production of this ligninase in biomass crops can reduce the needs for AFEX pretreatment.

  • ·        de Boer H.A., Zhang Y.Z., Collins and C.A. Reddy (1988). Analysis of nucleotide sequences of two ligninase cDNAs from a white-rot filamentous fungus, Phanerochaete chrysosporium. Gene: 69(2):369.

  • ·        Eggeman, T. and Elander, R.T. 2006. Process and economic analysis of pretreatment technologies. Bioresource Tehnology 96: 2019-2025.
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  • ·        Sticklen, M. 2006a. Plant genetic engineering to improve biomass characterization for biofuels. Curr. Opin. Biotech. 17(3): 315-319.

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