Abstract
A successful bioeconomy depends on the manifestation of biorefineries
that entirely convert renewable resources to valuable products and
energies. Here, the poorly exploited hemicellulose fraction (HF) from
beech wood organosolv processing was applied for isobutanol production
with Corynebacterium glutamicum. To enable growth of C.glutamicum on HF,
we integrated genes required for D-xylose and l-arabinose metabolization
into two of 16 systematically identified and novel chromosomal
integration loci. Under aerobic conditions, this engineered strain CArXy
reached growth rates up to 0.34 +/- 0.02h(-1) on HF. Based on CArXy, we
developed the isobutanol producer strain CIsArXy, which additionally
(over)expresses genes of the native l-valine biosynthetic and the
heterologous Ehrlich pathway. CIsArXy produced 7.2 +/- 0.2mM (0.53 +/-
0.02gL(-1)) isobutanol on HF at a carbon molar yield of 0.31 +/- 0.02
C-mol isobutanol per C-mol substrate (d-xylose + l-arabinose) in an
anaerobic zero-growth production process.
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