Pseudomonas putida as a platform for medium-chain length α,ω-diol production: Opportunities and challenges

Abstract

Medium-chain-length α,ω-diols (mcl-diols) play an important role in polymer production, traditionally depending on energy-intensive chemical processes. Microbial cell factories offer an alternative, but conventional strains like Escherichia coli and Saccharomyces cerevisiae face challenges in mcl-diol production due to the toxicity of intermediates such as alcohols and acids. Metabolic engineering and synthetic biology enable the engineering of non-model strains for such purposes with P. putida emerging as a promising microbial platform. This study reviews the advancement in diol production using P. putida and proposes a four-module approach for the sustainable production of diols. Despite progress, challenges persist, and this study discusses current obstacles and future opportunities for leveraging P. putida as a microbial cell factory for mcl-diol production. Furthermore, this study highlights the potential of using P. putida as an efficient chassis for diol synthesis.

FIGURE 1

Applications of medium‐chain‐length aliphatic α,ω‐diols.

FIGURE 2

The proposed four‐module mcl‐diol synthesis pathway in P. putida KT2440. Genes deleted are represented in red arrow while genes overexpressed are in green arrow. Black arrows present the native genes of P putida. Grey arrows showcase the robust PHA and rhamnolipids synthesis pathways. (A) Module a: mcl‐fatty acid supply module from glucose; (B) Module b: fatty acid reduction module; (C) Module c: monoester and diester synthesis module, and (D) Module d: diester hydrolysis module. ADH, alcohol dehydrogenase; AHR, aldehyde reductase; AlkB, alkane monooxygenase; AlkG, rubredoxin; AlkK, acyl‐CoA‐synthase; AlkL, outer membrane protein; AlkT, rubredoxin reductase; Atf1, alcohol acetyltransferase; Crc, catabolite repression control protein; Est, esterase; MmCAR, carboxylic acid reductase from Mycobacterium marinum; FadA, 3‐ketoacyl‐CoA thiolase; FadB, enoyl‐CoA hydratase/3‐hy‐droxyacyl‐CoA dehydrogenase; FadD, long‐chain fatty acyl‐CoA synthetase; FadE, acyl‐CoA dehydrogenase; G1P, D‐glucose‐1‐phosphate; G6P, D‐glucose‐6‐phosphate; HAAs, 3‐(3‐hydroxyalkanoyloxy)alkanoic acids; Hfq, RNA‐binding protein; PHA, polyhydroxyalkanoate; PhaC, PHA polymerase; PhaG, 3‐hydroxy acyl‐ACP acyl‐transferase; PhaJ, (R)‐specific enoyl‐CoA hydratase; PhaZ, PHA depolymerase; PPTase, phosphopantetheinyl transferase; RhlABC, rhamnosyltransferases; TE, thioesterase; TesA, Acyl‐CoA thioesterase I.