Lignin bioconversion

Proposed scheme for the conversion of phenolic compounds, a response to the inhibitory phenolic compounds by S. c.

Salvatore FuscoMaurizio Bettiga, Lisbeth Olsson and Carl Johan Franzén

Our group has shown that the presence of several phenolic compounds in biomass hydrolysates impacts their fermentability and, in turn, the ethanol productivity of S. cerevisiae. In particular, some chemical features have been identified as toxicity determinants; e.g. the chemical nature of the substituents on the phenolic ring. For this reason, it is reasonable to engineer more robust S. cerevisiae strains that could modify such compounds, thus being able to deal with their detrimental effects. It would be even better if it were possible to produce additional valuable products, while detoxifying the pre-treated lignocellulosic feedstock.
Heme-dependent monooxygenases, also referred to as cytochrome P450 monoxygenases or CYPs are a heterogeneous family of enzymes, which catalyze a wide range of oxidative reactions. Their substrates include steroids, fatty acids, pheromones, leukotrienes, and prostaglandins, as well as drugs and carcinogens. Interestingly, cytochrome P450s have been reported to be able to modify phenolic compounds and are therefore a valuable class of enzymes to be used for our purposes. Moreover, cytochrome P450 are well known for their substrate promiscuity, which is a crucial feature when trying to produce more efficient enzymes through protein engineering. Genes encoding for such enzymes will be inserted into the genome of industrially relevant strains of S. cerevisiae currently used for bioethanol production with the aim of achieving phenolic bioconversions during fermentation.

This project is part of BioBUF and is financed by FORMAS and Västra Götalandsregionen.


Published: Wed 08 Jul 2015. Modified: Thu 08 Dec 2016