BIOLOGICAL FUNNELING OF AROMATIC PHENOLICS FROM TRANSGENIC PLANTS
File(s)
Date
2022-05Author
Umana Chapeton, German Eduardo
Advisor(s)
Noguera, Daniel R.
Metadata
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ABSTRACT
Lignocellulosic biomass is an abundant renewable resource primarily formed by cellulose, hemicellulose, and lignin. The economic and environmental sustainability of biomass biorefineries is dependent on valorizing all the main biomass components and on the ability to use mild and cost-effective biomass deconstruction techniques. The conversion of lignocellulose into fuels and commodity products is hindered by the recalcitrance and complexity of lignin, therefore, plants have been genetically engineered to facilitate its deconstruction and to improve product recovery.
For this study, we selected transgenic plants modified to express a bacterial quinate and shikimate utilization B (qsuB) gene, that increases the accumulation of easily extractable protocatechuic acid (PCA) in the plant cell wall. We evaluated the effectiveness of an alkaline pretreatment process to extract PCA and other phenolics from wild-type (WT) and QsuB-transgenic lines of Arabidopsis, poplar, and sorghum, and then, convert them to 2-pyrone-4,6-dicarboxylic acid (PDC) with an engineered strain of Novosphingobium aromaticivorans. All QsuB transgenic lines outperformed their WT counterparts with respect to PDC yields, and the bacteria was able to metabolize and produce PDC from free and conjugated phenolics. Furthermore, Arabidopsis transgenics had the highest PDC yield per unit of biomass (~5 % w/w), sorghum QsuB line had the second-best PDC yields (~1.1 % w/w), and the transgenic QsuB poplar lines had the lowest PDC yield (~0.4 % w/w).
Subject
PDC
QsuB
lignin
bioproduct
aromatic
Permanent Link
http://digital.library.wisc.edu/1793/83224Type
Thesis