Expanding Pseudomonas taiwanensis VLB120's acyl‐CoA portfolio: Propionate production in mineral salt medium

Abstract

Abstract As one of the main precursors, acetyl‐CoA leads to the predominant production of even‐chain products. From an industrial biotechnology perspective, extending the acyl‐CoA portfolio of a cell factory is vital to producing industrial relevant odd‐chain alcohols, acids, ketones and polyketides. The bioproduction of odd‐chain molecules can be facilitated by incorporating propionyl‐CoA into the metabolic network. The shortest pathway for propionyl‐CoA production, which relies on succinyl‐CoA catabolism encoded by the sleeping beauty mutase operon, was evaluated in Pseudomonas taiwanensis VLB120. A single genomic copy of the sleeping beauty mutase genes scpA, argK and scpB combined with the deletion of the methylcitrate synthase PVLB_08385 was sufficient to observe propionyl‐CoA accumulation in this Pseudomonas. The chassis' capability for odd‐chain product synthesis was assessed by expressing an acyl‐CoA hydrolase, which enabled propionate synthesis. Three fed‐batch strategies during bioreactor fermentations were benchmarked for propionate production, in which a maximal propionate titre of 2.8 g L−1 was achieved. Considering that the fermentations were carried out in mineral salt medium under aerobic conditions and that a single genome copy drove propionyl‐CoA production, this result highlights the potential of Pseudomonas to produce propionyl‐CoA derived, odd‐chain products.