Accumulation of recombinant cellobiohydrolase and endoglucanase in the leaves of mature transgenic sugar cane

Mark D. Harrison, Jason Geijskes, Heather D. Coleman, Kylie Shand, Mark Kinkema, Anthony Palupe, Rachael Hassall, Manuel Sainz, Robyn Lloyd, Stacy Miles, James L. Dale

Research output: Contribution to journalArticle

67 Scopus citations

Abstract

A major strategic goal in making ethanol from lignocellulosic biomass a cost-competitive liquid transport fuel is to reduce the cost of production of cellulolytic enzymes that hydrolyse lignocellulosic substrates to fermentable sugars. Current production systems for these enzymes, namely microbes, are not economic. One way to substantially reduce production costs is to express cellulolytic enzymes in plants at levels that are high enough to hydrolyse lignocellulosic biomass. Sugar cane fibre (bagasse) is the most promising lignocellulosic feedstock for conversion to ethanol in the tropics and subtropics. Cellulolytic enzyme production in sugar cane will have a substantial impact on the economics of lignocellulosic ethanol production from bagasse. We therefore generated transgenic sugar cane accumulating three cellulolytic enzymes, fungal cellobiohydrolase I (CBH I), CBH II and bacterial endoglucanase (EG), in leaves using the maize PepC promoter as an alternative to maize Ubi1 for controlling transgene expression. Different subcellular targeting signals were shown to have a substantial impact on the accumulation of these enzymes; the CBHs and EG accumulated to higher levels when fused to a vacuolar-sorting determinant than to an endoplasmic reticulum-retention signal, while EG was produced in the largest amounts when fused to a chloroplast-targeting signal. These results are the first demonstration of the expression and accumulation of recombinant CBH I, CBH II and EG in sugar cane and represent a significant first step towards the optimization of cellulolytic enzyme expression in sugar cane for the economic production of lignocellulosic ethanol.

Original languageEnglish (US)
Pages (from-to)884-896
Number of pages13
JournalPlant Biotechnology Journal
Volume9
Issue number8
DOIs
StatePublished - Oct 2011

Keywords

  • Biofuel
  • Cellulosic ethanol
  • Expression
  • Recombinant cellulase
  • Subcellular targeting
  • Transgenic sugar cane

ASJC Scopus subject areas

  • Biotechnology
  • Agronomy and Crop Science
  • Plant Science

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    Harrison, M. D., Geijskes, J., Coleman, H. D., Shand, K., Kinkema, M., Palupe, A., Hassall, R., Sainz, M., Lloyd, R., Miles, S., & Dale, J. L. (2011). Accumulation of recombinant cellobiohydrolase and endoglucanase in the leaves of mature transgenic sugar cane. Plant Biotechnology Journal, 9(8), 884-896. https://doi.org/10.1111/j.1467-7652.2011.00597.x