Bioproduction of propionic acid using levulinic acid by engineered Pseudomonas putida

Abstract

The present study elaborates on the propionic acid (PA) production by the well-known microbial cell factory Pseudomonas putida EM42 and its capacity to utilize biomass-derived levulinic acid (LA). Primarily, the P. putida EM42 strain was engineered to produce PA by deleting the methylcitrate synthase (PrpC) and propionyl-CoA synthase (PrpE) genes. Subsequently, a LA-inducible expression system was employed to express yciA (encoding thioesterase) from Haemophilus influenzae and ygfH (encoding propionyl-CoA: succinate CoA transferase) from Escherichia coli to improve the PA production by up to 10-fold under flask scale cultivation. The engineered P. putida EM42:ΔCE:yciA:ygfH was used to optimize the bioprocess to further improve the PA production titer. Moreover, the fed-batch fermentation performed under optimized conditions in a 5 L bioreactor resulted in the titer, productivity, and molar yield for PA production of 26.8 g/L, 0.3 g/L/h, and 83%, respectively. This study, thus, successfully explored the LA catabolic pathway of P. putida as an alternative route for the sustainable and industrial production of PA from LA.

High-Yield Production of Propionate from 1,2-Propanediol by Engineered Pseudomonas putida KT2440, a Robust Strain with Highly Oxidative Capacity

“…Recently, Tiwari and Lee elaborated a PA production route from biomass-derived levulinic acid by P. putida EM42, a derivative strain from P. putida KT2440. However, the theoretical yield of 0.64 g/g with an experimental conversion rate of 83% is still not satisfactory . In this study, we designed a new route for PA production from 1,2-PDO, in which one molecule of H 2 O was removed from 1,2-PDO by glycerol dehydratase to generate propionaldehyde, followed by oxidation to form PA by the endogenous aldehyde dehydrogenases in KT2440, with a high theoretical yield of 97% (g/g).…”

“…However, the theoretical yield of 0.64 g/g with an experimental conversion rate of 83% is still not satisfactory. 35 In this study, we designed a new route for PA production from 1,2-PDO, in which one molecule of H 2 O was removed from 1,2-PDO by glycerol dehydratase to generate propionaldehyde, followed by oxidation to form PA by the endogenous aldehyde dehydrogenases in KT2440, with a high theoretical yield of 97% (g/g). In the designed pathway, expression of only one exogenous glycerol dehydratase was needed with minimal genetic modification required, which would reduce the metabolic burden on the engineered P. putida to a certain extent.…”