Location: Commodity Utilization ResearchTitle: Prediction of carboxylic and polyphenolic chemical feedstock quantities in sweet sorghum
Submitted to: Energy and Fuels
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2018
Publication Date: 3/5/2018
Citation: Uchimiya, M., Knoll, J.E. 2018. Prediction of carboxylic and polyphenolic chemical feedstock quantities in sweet sorghum. Energy and Fuels. 32:5252-5263.
Interpretive Summary: Carboxylates and other specialized chemicals are important feedstock to produce renewable biobased products including plastics and composite materials. This study developed methods to predict the amounts of specialized chemical produced by different sweet sorghum breeds. The method is based on simple visible light absorption, or fluorescence reflectance. Both genetic and environmental effects influence the ability of sweet sorghum to accumulate carboxylates and polyphenols. Developed methods will allow feedstock accounting for bioenergy plants and chemical factories.
Technical Abstract: Quantitative chemical phenotyping is on increasing demand to develop sweet sorghum genotypes targeted to accumulate carboxylate and polyphenolic secondary products as the plant-derived feedstocks for renewable biobased products including plastics. Of 24 sweet sorghum genotypes investigated, No.5 Gambela (i) uniquely accumulated trans-aconitic acid and redox-active secondary products, and (ii) was most susceptible to lodging and was latest flowering. Partial least squares (PLS) calibration and prediction models were developed based on UV/visible spectra of juice and bagasse. Two-year (2015-2016) field experiment indicated the accumulation of secondary products (carboxylates, polyphenolic chromophores, and salts) at the expense of primary sugar production. Liquid- (sugar and methanol extract of bagasse) and solid-phase (bagasse without extraction) fluorescence excitation emission spectrophotometry with parallel factor analysis (EEM/PARAFAC) indicated the replacement of aromatic fingerprints by aliphatic structures from 2015 to 2016 for bagasse. Oppositely, aromatic fluorophores accumulated in juice by year, along with an increased UV/visible absorbance (320 nm). Linear correlations (Pearson’s) were obtained to predict the interplay of the environmental (planting year) and genotype factors on growth and chemical traits of sweet sorghum feedstock.