Phylogeny in defining model plants for lignocellulosic ethanol production: a comparative study of Brachypodium distachyon, wheat, maize, and Miscanthus x giganteus leaf and stem biomass

• Published in: PloS one 2014-08, Vol.9 (8), p.e103580
• Main Authors: Meineke, Till, Manisseri, Chithra, Voigt, Christian A
• Format: Article
• Language: English
• Subjects: Alcohol; Alcohol industry; Alternative energy sources; Analysis; Biochemistry; Biodiesel fuels; Biofuels; Biology and Life Sciences; Biomass; Biomass energy; Biomass energy production; Brachypodium distachyon; Cell Wall - chemistry; Cell Wall - metabolism; Cell walls; Cellulose; Climate change; Climate change mitigation; Comparative studies; Conversion; Corn; Crops; DNA, Ribosomal Spacer - genetics; Energy; Energy crops; Energy resources; Ethanol; Ethanol - metabolism; Fermentation; Fossil fuels; Fuel industry; Genes, Plant; Grasses; Leaves; Lignin; Lignin - biosynthesis; Lignin - chemistry; Lignocellulose; Miscanthus giganteus; Monosaccharides - chemistry; Monosaccharides - metabolism; Optimization; Phylogenetics; Phylogeny; Plant biomass; Plant Leaves - chemistry; Plant Leaves - genetics; Plant Leaves - metabolism; Plant species; Plant Stems - chemistry; Plant Stems - genetics; Plant Stems - metabolism; Plants (botany); Poaceae - chemistry; Poaceae - genetics; Poaceae - metabolism; Principal components analysis; Process parameters; Production data; Production processes; Qualitative analysis; Raw materials; Saccharification; Saccharomyces cerevisiae - metabolism; Stems; Triticum aestivum; Wheat; Zea mays
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0103580

The production of ethanol from pretreated plant biomass during fermentation is a strategy to mitigate climate change by substituting fossil fuels. However, biomass conversion is mainly limited by the recalcitrant nature of the plant cell wall. To overcome recalcitrance, the optimization of the plant cell wall for subsequent processing is a promising approach. Based on their phylogenetic proximity to existing and emerging energy crops, model plants have been proposed to study bioenergy-related cell wall biochemistry. One example is Brachypodium distachyon, which has been considered as a general model plant for cell wall analysis in grasses. To test whether relative phylogenetic proximity would be sufficient to qualify as a model plant not only for cell wall composition but also for the complete process leading to bioethanol production, we compared the processing of leaf and stem biomass from the C3 grasses B. distachyon and Triticum aestivum (wheat) with the C4 grasses Zea mays (maize) and Miscanthus x giganteus, a perennial energy crop. Lambda scanning with a confocal laser-scanning microscope allowed a rapid qualitative analysis of biomass saccharification. A maximum of 108-117 mg ethanol·g(-1) dry biomass was yielded from thermo-chemically and enzymatically pretreated stem biomass of the tested plant species. Principal component analysis revealed that a relatively strong correlation between similarities in lignocellulosic ethanol production and phylogenetic relation was only given for stem and leaf biomass of the two tested C4 grasses. Our results suggest that suitability of B. distachyon as a model plant for biomass conversion of energy crops has to be specifically tested based on applied processing parameters and biomass tissue type.