Engineering the cell wall by reducing de-methyl-esterified homogalacturonan improves saccharification of plant tissues for bioconversion

Proc Natl Acad Sci U S A. 2010 Jan 12;107(2):616-21. doi: 10.1073/pnas.0907549107. Epub 2009 Dec 22.

Abstract

Plant cell walls represent an abundant, renewable source of biofuel and other useful products. The major bottleneck for the industrial scale-up of their conversion to simple sugars (saccharification), to be subsequently converted by microorganisms into ethanol or other products, is their recalcitrance to enzymatic saccharification. We investigated whether the structure of pectin that embeds the cellulose-hemicellulose network affects the exposure of cellulose to enzymes and consequently the process of saccharification. Reduction of de-methyl-esterified homogalacturonan (HGA) in Arabidopsis plants through the expression of a fungal polygalacturonase (PG) or an inhibitor of pectin methylesterase (PMEI) increased the efficiency of enzymatic saccharification. The improved enzymatic saccharification efficiency observed in transformed plants could also reduce the need for acid pretreatment. Similar results were obtained in PG-expressing tobacco plants and in PMEI-expressing wheat plants, indicating that reduction of de-methyl-esterified HGA may be used in crop species to facilitate the process of biomass saccharification.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / enzymology
  • Arabidopsis / genetics*
  • Arabidopsis / physiology
  • Aspergillus niger / genetics
  • Biofuels
  • Biomass
  • Carboxylic Ester Hydrolases / genetics
  • Cell Wall / drug effects
  • Cell Wall / physiology*
  • Cellulose / metabolism
  • Cellulose / pharmacology
  • DNA Primers
  • Genetic Vectors
  • Hypocotyl / metabolism
  • Nicotiana / genetics*
  • Nicotiana / physiology
  • Pectins / chemistry
  • Pectins / metabolism
  • Pectins / pharmacology*
  • Plant Cells
  • Plant Leaves / metabolism
  • Plant Physiological Phenomena*
  • Plant Proteins / genetics
  • Polygalacturonase / metabolism
  • Polysaccharides / metabolism
  • Polysaccharides / pharmacology
  • RNA, Plant / genetics
  • Tissue Engineering / methods*

Substances

  • Biofuels
  • DNA Primers
  • Plant Proteins
  • Polysaccharides
  • RNA, Plant
  • hemicellulose
  • Pectins
  • Cellulose
  • Carboxylic Ester Hydrolases
  • pectinesterase
  • Polygalacturonase
  • polygalacturonic acid