초록
<P><B>Background</B></P><P>A future bioeconomy relies on the efficient use of renewable resources for energy and material product supply. In this context, biorefineries have been developed and play a key role in converting lignocellulosic residues. Although a holistic use of the biomass feed is desired, side streams evoke in current biorefinery approaches. To ensure profitability, efficiency, and sustainability of the overall conversion process, a meaningful valorization of these materials is needed. Here, a so far unexploited side stream derived from fast pyrolysis of wheat straw—pyrolysis water—was used for production of 1,2-propanediol in microbial fermentation with engineered <I>Corynebacterium glutamicum</I>.</P><P><B>Results</B></P><P>A protocol for pretreatment of pyrolysis water was established and enabled growth on its major constituents, acetate and acetol, with rates up to 0.36 ± 0.04 h<SUP>−1</SUP>. To convert acetol to 1,2-propanediol, the plasmid pJUL<I>gldA</I> expressing the glycerol dehydrogenase from <I>Escherichia coli</I> was introduced into <I>C. glutamicum</I>. 1,2-propanediol was formed in a growth-coupled biotransformation and production was further increased by construction of <I>C. glutamicum</I> Δ<I>pqo</I> Δ<I>aceE</I> Δ<I>ldhA</I> Δ<I>mdh</I> pJUL<I>gldA</I>. In a two-phase aerobic/microaerobic fed-batch process with pyrolysis water as substrate, this strain produced 18.3 ± 1.2 mM 1,2-propanediol with a yield of 0.96 ± 0.05 mol 1,2-propanediol per mol acetol and showed an overall volumetric productivity of 1.4 ± 0.1 mmol 1,2-propanediol L<SUP>−1</SUP> h<SUP>−1</SUP>.</P><P><B>Conclusions</B></P><P>This study implements microbial fermentation into a biorefinery based on pyrolytic liquefaction of lignocellulosic biomass and accesses a novel value chain by valorizing the side stream pyrolysis water for 1,2-PDO production with engineered <I>C. glutamicum</I>. The established bioprocess operated at maximal product yield and accomplished the so far highest overall volumetric productivity for microbial 1,2-PDO production with an engineered producer strain. Besides, the results highlight the potential of microbial conversion of this biorefinery side stream to other valuable products.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (10.1186/s13068-017-0969-8) contains supplementary material, which is available to authorized users.</P>