Lactobacillus reuteri NAD(P)H oxidase: Properties and coexpression with propanediol-utilization enzymes for enhancing 3-hydroxypropionic acid production from 3-hydroxypropionaldehyde.

Lactobacillus reuteri metabolizes glycerol through propanediol-utilization (Pdu) pathway to 1,3-propanediol (1,3-PD) via 3-hydroxypropionaldehyde (3-HPA) as intermediate. In the resting cells, the oxidized co-factor obtained in the reaction is regenerated by simultaneous oxidation of 3-HPA to 3-hydroxypropionic acid (3-HP) using propionaldehyde dehydrogenase (PduP), phosphotransacylase (PduL) and propionate kinase (PduW). We have earlier shown that the use of resting cells of recombinant Escherichia coli expressing the oxidative pathway gives the highest theoretical yield of 1 mol 3-HP per mol 3-HPA but is limited by cofactor depletion.