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Twenty-First Symposium on Biotechnology for Fuels and Chemicals

Part of the series Applied Biochemistry and Biotechnology pp 617-632

Influence of Lignocellulose-Derived Aromatic Compounds on Oxygen-Limited Growth and Ethanolic Fermentation by Saccharomyces cerevisiae

  • Simona LarssonAffiliated withDepartment of Applied Microbiology, Lund University/Lund Institute of Technology
  • , Alexis Quintana-SáinzAffiliated withDepartment of Applied Microbiology, Lund University/Lund Institute of Technology
  • , Anders ReimannAffiliated withSTFI, Swedish Pulp and Paper Research Institute
  • , Nils-Olof NilvebrantAffiliated withSTFI, Swedish Pulp and Paper Research Institute
  • , Leif J. JönssonAffiliated withDepartment of Applied Microbiology, Lund University/Lund Institute of Technology

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Abstract

Phenolic compounds released and generated during hydrolysis inhibit fermentation of lignocellulose hydrolysates to ethanol by Saccharomyces cerevisiae. A wide variety of aromatic compounds form from lignin, which is partially degraded during acid hydrolysis of the lignocellulosic raw material. Aromatic compounds may also form as a result of sugar degradation and are present in wood as extractives. The influence of hydroxy-methoxy-benzaldehydes, diphenols/quinones, and phenylpropane derivatives on S. cerevisiae cell growth and ethanol formation was assayed using a defined medium and oxygen-limited conditions. The inhibition effected by the hydroxy-methoxybenzaldehydes was highly dependent on the positions of the substituents. A major difference in inhibition by the oxidized and reduced form of a diphenol/quinone was observed, the oxidized form being the more inhibitory. The phenylpropane derivatives were examined with respect to difference in toxicity depending on the oxidation-reduction state of the γ-carbon, the presence and position of unsaturated bonds in the aliphatic side chain, and the number and identity of hydroxyl and methoxyl substituents. Transformations of aromatic compounds occurring during the fermentation included aldehyde reduction, quinone reduction, and double bond saturation. Aromatic alcohols were detected as products of reductions of the corresponding aldehydes, namely hydroxy-methoxy-benzaldehydes and coniferyl aldehyde. High molecular mass compounds and the corresponding diphenol were detected as products of quinone reduction. Together with coniferyl alcohol, dihydroconiferyl alcohol was identified as a major transformation product of coniferyl aldehyde.

Index Entries

Aromatic compounds inhibitors S. Cerevisiae ethanolic fermentation growth