Efficient poly(3-hydroxypropionate) production from glycerol using Lactobacillus reuteri and recombinant Escherichia coli harboring L. reuteri propionaldehyde dehydrogenase and Chromobacterium sp. PHA synthase genes

• P(3HP) production via two-stage process using L. reuteri and recombinant E. coli.
• Glycerol conversion to reuterin with resting cells of L. reuteri in fed-batch mode.
• Co-expression of L. reuteri PduP and Chromobacterium sp. PHA synthase in E. coli.
• Two-stage process gives high P(3HP) content of 40% w/w cell dry weight.

Poly(3-hydroxypropionate), P(3HP), is a polymer combining good biodegradability with favorable material properties. In the present study, a production system for P(3HP) was designed, comprising conversion of glycerol to 3-hydroxypropionaldehyde (3HPA) as equilibrium mixture with 3HPA-hydrate and -dimer in aqueous system (reuterin) using resting cells of native Lactobacillus reuteri in a first stage followed by transformation of the 3HPA to P(3HP) using recombinant Escherichia coli strain co-expressing highly active coenzyme A-acylating propionaldehyde dehydrogenase (PduP) from L. reuteri and polyhydroxyalkanoate synthase (PhaCcs) from Chromobacterium sp. P(3HP) content of up to 40% (w/w) cell dry weight was reached, and the yield with respect to the reuterin consumed by the cells was 78%. Short biotransformation period (4.5 h), lack of additives or expensive cofactors, and use of a cheap medium for cultivation of the recombinant strain, provides a new efficient and potentially economical system for P(3HP) production.