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Ethanol yields and cell wall properties in divergently bred switchgrass genotypes
- Sarath, Gautam, Dien, Bruce, Saathoff, Aaron J., Vogel, Kenneth P., Mitchell, Robert B., Chen, Han
- Bioresource technology 2011 v.102 no.20 pp. 9579
- Panicum virgatum, acid treatment, biofuels, biomass, cell walls, ethanol, ethanol production, genotype, lignification, lignin, plant breeding, pretreatment, sclerenchyma, stems, xylan
- Genetic modification of herbaceous plant cell walls to increase biofuels yields is a primary bioenergy research goal. Using two switchgrass populations developed by divergent breeding for ruminant digestibility, the contributions of several wall-related factors to ethanol yields was evaluated. Field grown low lignin plants significantly out yielded high lignin plants for conversion to ethanol by 39.1% and extraction of xylans by 12%. However, across all plants analyzed, greater than 50% of the variation in ethanol yields was attributable to changes in tissue and cell wall architecture, and responses of stem biomass to dilute-acid pretreatment. Although lignin levels were lower in the most efficiently converted genotypes, no apparent correlation were seen in the lignin monomer G/S ratios. Plants with higher ethanol yields were associated with an apparent decrease in the lignification of the cortical sclerenchyma, and a marked decrease in the granularity of the cell walls following dilute-acid pretreatment.