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Carbonyl Inhibition and Detoxification in Butanol and Carboxylic Acid Fermentation of Lignocellulosic Biomass

Zhang, Yu
http://orcid.org/0000-0002-7186-7336
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1636389379718103

Abstract Details

2021, PhD, University of Cincinnati, Engineering and Applied Science: Chemical Engineering.
Biofuels and bioproducts derived from lignocellulosic biomass have been considered as great alternatives to petroleum-based fuels and chemicals. However, inhibitory by-products from biomass pretreatment severely impede the following microbial fermentation process. The present dissertation aims to identifying the potent carbonyl inhibitors in biomass prehydrolysates, to quantitatively evaluate the detoxification approaches, and improve the cost-effectiveness of biofuel and biochemical production. The first research interest of this study is to establish a comprehensive analytical approach for carbonyl inhibitor in biomass prehydrolysate. Therefore, a gas chromatography coupled with mass spectroscopy (GC/MS) method was developed to identify and quantify 60 different aldehydes and ketones from dilute acid prehydrolysates. By comparing two extraction approaches, sodium bisulfite extraction selectively isolated the highly reactive aldehydes/ketones at extremely low concentrations, while direct solvent extraction resulted in the higher recovery for the quantitative analysis, especially for furan derivatives and aromatic monomers. Specifically, 2,3-dihydroxybenzaldehyde has been identified as a potent inhibitor with significant adverse effect on ethanol and acetone-butanol-ethanol (ABE) fermentation. The second part of this dissertation focuses on the effective detoxification strategies for ABE fermentation. Based on the GC/MS method, overliming and activated carbon detoxification have been quantitatively evaluated regarding to the inhibitor removal and ABE fermentation. The result indicated that overliming and activated carbon (AC) alone could not make the prehydrolysates fermentable. To address this problem, a two-step method (sequential overliming and AC) was established for a remarkable fermentability and satisfactory butanol yield (0.22 g/g sugar), which suggested the excellent synergistic effect of overliming and AC detoxification on ABE fermentation. The difference in removing the dialdehydes/diketones and phenolic acids by overliming and AC could be the potential reason behind their synergic effect. It is believed that AC was more effective in removing phenolic acids due to their hydrophobicity and overliming was more selective in removing certain dialdehydes and diketones due to the base-catalyzed aldo-condensation reactions. The third part of this study aims at expanding the cost-effective prehydrolysate utilization by developing a simplified peptone assisted in-situ detoxification method for carboxylic acid production. The effects of two major factors (temperature and peptone) have been investigated in mixed culture carboxylic acid fermentation. The result suggested that temperature is a factor that altered the carboxylic acid profiles because of the variation of microbial community. It was found that peptone significantly enhanced carboxylic acid production at 35 °C (mesophilic condition), however, it appeared to be less effective under thermophilic condition due to the more severe carbonyl inhibition at higher temperature. The result indicated that peptone enabled a significant promotion on mixed culture carboxylic acid fermentation as a nitrous nutrient, and also enhanced the biomass prehydrolysate fermentability under mesophilic condition. To further investigate the digestion of sulfite pretreated aspen, carboxylic acid fermentation was carried out in three different approaches, including mixed culture fermentation without external enzyme, separated hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation. The result suggested that SHF process under mesophilic condition achieved a desirable carboxylic acid yield without additional nutrient, as the acetic acid equivalent production reached 27.52±0.44 g/L.
Maobing Tu, Ph.D. (Committee Chair)
Yoonjee Park (Committee Member)
Junhang Dong, Ph.D. (Committee Member)
Dwight Anderson, PhD (Committee Member)
189 p.
Chemical Engineering
Carbonyl inhibition; Butanol fermentation; Carboxylic acid fermentation; Biomass prehydrolysate; GC/MS; Detoxification

Recommended Citations

Citations

  • Zhang, Y. (2021). Carbonyl Inhibition and Detoxification in Butanol and Carboxylic Acid Fermentation of Lignocellulosic Biomass [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1636389379718103

    APA Style (7th edition)

  • Zhang, Yu. Carbonyl Inhibition and Detoxification in Butanol and Carboxylic Acid Fermentation of Lignocellulosic Biomass. 2021. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1636389379718103.

    MLA Style (8th edition)

  • Zhang, Yu. "Carbonyl Inhibition and Detoxification in Butanol and Carboxylic Acid Fermentation of Lignocellulosic Biomass." Doctoral dissertation, University of Cincinnati, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1636389379718103

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Cincinnati and OhioLINK.
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