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Maize Feedstocks With Improved Digestibility Reduce the Costs and Environmental Impacts of Biomass Pretreatment and Saccharification

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Maize Feedstocks With Improved Digestibility Reduce the Costs and Environmental Impacts of Biomass Pretreatment and Saccharification

Andres F Torres et al. Biotechnol Biofuels.

Abstract

Background: Despite the recognition that feedstock composition influences biomass conversion efficiency, limited information exists as to how bioenergy crops with reduced recalcitrance can improve the economics and sustainability of cellulosic fuel conversion platforms. We have compared the bioenergy potential-estimated as total glucose productivity per hectare (TGP)-of maize cultivars contrasting for cell wall digestibility across processing conditions of increasing thermochemical severity. In addition, exploratory environmental impact and economic modeling were used to assess whether the development of bioenergy feedstocks with improved cell wall digestibility can enhance the environmental performance and reduce the costs of biomass pretreatment and enzymatic conversion.

Results: Systematic genetic gains in cell wall degradability can lead to significant advances in the productivity (TGP) of cellulosic fuel biorefineries under low severity processing; only if gains in digestibility are not accompanied by substantial yield penalties. For a hypothetical maize genotype combining the best characteristics available in the evaluated cultivar panel, TGP under mild processing conditions (~3.7 t ha(-1)) matched the highest realizable yields possible at the highest processing severity. Under this scenario, both, the environmental impacts and processing costs for the pretreatment and enzymatic saccharification of maize stover were reduced by 15 %, given lower chemical and heat consumption.

Conclusions: Genetic improvements in cell wall composition leading to superior cell wall digestibility can be advantageous for cellulosic fuel production, especially if "less severe" processing regimes are favored for further development. Exploratory results indicate potential cost and environmental impact reductions for the pretreatment and enzymatic saccharification of maize feedstocks exhibiting higher cell wall degradability. Conceptually, these results demonstrate that the advance of bioenergy cultivars with improved biomass degradability can enhance the performance of currently available biomass-to-ethanol conversion systems.

Keywords: Biomass yield; Cell wall digestibility; Maize; Pretreatment; Refinery; Technoeconomic.

Figures

Fig. 1
Fig. 1
Principal component biplot displaying the classification of a panel of Northern-European forage maize cultivars based on stem fiber and cell wall components. Cultivars were classified based on their DINAG ratings as either having “Excellent” (Green), “Good” (Blue), or “Poor” (Red) cell wall digestibility. The five proprietary hybrids carrying either the bm3 or bm1 mutations were cataloged as “Cell Wall Mutants” (Purple). Black vectors summarize the correlation between relevant feedstock compositional characters and the corresponding principal component
Fig. 2
Fig. 2
Conversion performance of four distinct cultivar classes (diverging in cell wall digestibility) for A Glu-Con, B Glu-Rel, and C Glu-Sol across pretreatments of increasing severity. Glu-Con is the percentage of total cell wall glucose released after pretreatment and enzymatic saccharification. Glu-Rel is the amount of glucose (g) released from 1 kg of dry biomass after pretreatment and enzymatic saccharification. Glu-Sol is the absolute amount of glucose (g) released from 1 kg of dry biomass into pretreatment liquors following thermochemical processing. Within each processing severity regime, similar letters above bars indicate non-significant differences according to a Tukey HSD test (P = 0.05)
Fig. 3
Fig. 3
Performance of four distinct cultivar classes (diverging in cell wall digestibility) across pretreatments of increasing severity for A TGP and B furfural release into pretreatment liquors. Within each processing severity regime, similar letters above bars indicate non-significant differences according to a Tukey HSD test (P = 0.05)
Fig. 4
Fig. 4
Relative environmental and economic impacts (based on TGP) of scenarios II, III, and IV (refer to Table 4) relative to scenario I (benchmark)
Fig. 5
Fig. 5
Flow scheme for the production of cellulosic ethanol from maize lignocellulosic biomass using dilute-acid pretreatment; dotted lines delimit the system boundary. During cellulosic ethanol production, the polysaccharide fraction (cellulose and hemicellulose) of plant lignocellulose is deconstructed via thermochemical pretreatment. The resulting slurry is neutralized to prevent enzyme limitations during the saccharification stage. Fermentation of saccharification broths yields ethanol

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References

    1. Weijde T, Alvim Kamei CL, Torres AF, Vermerris W, Dolstra O, Visser RGF, Trindade LM. The potential of C4 grasses for cellulosic biofuel production. Front Plant Sci. 2013;4:107. - PMC - PubMed
    1. Yang B, Wyman CE. Pretreatment: the key to unlocking low-cost cellulosic ethanol. Biofuels, Bioprod Bioref. 2007;2:26–40. doi: 10.1002/bbb.49. - DOI
    1. Mosier N, Wyman C, Dale B, Elander R, Lee Y, Holtzapple M, Ladisch M. Features of promising technologies for pretreatment of lignocellulosic biomass. Bioresource Technol. 2005;96:673–686. doi: 10.1016/j.biortech.2004.06.025. - DOI - PubMed
    1. Chen F, Dixon RA. Lignin modification improves fermentable sugar yields for biofuel production. Nat Biotechnol. 2007;25:759–761. doi: 10.1038/nbt1316. - DOI - PubMed
    1. Fu C, Mielenz JR, Xiao X, Ge Y, Hamilton CY, Rodriguez M, Chen F, Foston M, Ragauskas A, Bouton J, Dixon RA, Wang Z-Y. Genetic manipulation of lignin reduces recalcitrance and improves ethanol production from switchgrass. P Natl Acad Sci USA. 2011;108:3803–3808. doi: 10.1073/pnas.1100310108. - DOI - PMC - PubMed

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