Multistep Synthesis of (S)-3-Hydroxyisobutyric Acid from Glucose using Pseudomonas taiwanensis VLB120 B83 T7 Catalytic Biofilms

作者：Lang Karsten; Buehler Katja^*; Schmid Andreas

来源：Advanced Synthesis & Catalysis, 2015, 357(8): 1919-1927.

DOI：10.1002/adsc.201500205

• biofilms
• continuous process
• fermentation
• (S)-3-hydroxyisobutyric acid
• Pseudomonas

The chiral building block (S)-3-hydroxyisobutyric acid [(S)-3-HIBA] was produced either by conversion of isobutyric acid or directly from glucose utilizing cells of Pseudomonas taiwanensis VLB120 B83 T7 as catalysts. This strain carries a point mutation in the gene encoding 3-hydroxyisobutyrate dehydrogenase (mmsB), leading to its inactivation. The maximal specific activity in resting-cell biotransformations using isobutyric acid as substrate was 4.9 +/- 0.4 U g(cdw)(-1). Overexpression of the 2-ketoisovalerate pathway genes alsS, ilvC, and ilvD, and the introduction of kivd encoding 2-ketoacid decarboxylase resulted in the efficient fermentative synthesis of (S)-3-HIBA directly from glucose. Up to 22 mM (2.3 g L-1) (S)-3-HIBA were produced at 3.7 +/- 0.3 U g(cdw)(-1) in repeated batch experiments without observable product degradation. Utilizing a biofilm reactor it was possible to continuously produce up to 6 mM (0.63 g L-1) of (S)-3-hydroxyisobutyric acid with a volumetric productivity of 1.32 mmol((S)-3-HIBA) h(-1) L-1. Overall, the conversion of isobutyric acid to (S)-3-HIBA was found to be the rate-limiting step, leading to the accumulation of a mixture of (S)-3-hydroxyisobutyric acid and isobutyric acid. This study demonstrates for the first time the production of (S)-3-HIBA from renewable carbon in shake flasks and biofilm reactors and sets the stage for further optimizations towards the efficient production of 3-HIBA and its derivatives in continuous fermentations.

• 出版日期2015-5-26
• 单位TU Dortmund