Sulphide and oleic acid synergism in accelerating mcl-PHA biopolymer production in Pseudomonas aeruginosa MCC 5300 by modulating electron transport system

Document Type

Article

Publication Title

Biochemistry and Biophysics Reports

Abstract

Environmental concerns raised by petroleum-based plastics have sparked research on eco-friendly biodegradable polymers as alternatives. The medium chain length polyhydroxyalkanoates (mcl-PHA) are one such elastomeric polymer produced by a few bacteria that find various industrial, agricultural and biomedical applications. Besides its vast application, the low yield of wild-type bacterial strains and yield reduction due to reduced growth during prolonged cultivation in nutrient-limiting conditions limit industrial mcl-PHA production. In the present study, Pseudomonas aeruginosa MCC 5300 produced mcl-PHA of about 44.7 % CDW in tryptic soy broth (TSB) media containing oleic acid at 24 h of growth. The sulphide in media enhanced mcl-PHA content up to 86.5 % CDW in TSB media containing oleic acid at 24 h of growth. This is the first report of high mcl-PHA production at a short duration of 24 h in nutrient-enriched conditions. The oleic acid inhibited cytochrome c oxidase activity, shifting the electron flow from ubiquinol to cytochrome c pool. The sulphide increased the expression of bd-oxidase and enhanced electron flux through it, causing a rapid decline in the cellular NADH levels to maintain proton gradient and energy generation. The NADH reduction is compensated by excess mcl-PHA accumulated in bacteria. Hence, mcl-PHA maintains cellular redox-homeostasis during respiration using bd-oxidase.

DOI

10.1016/j.bbrep.2025.102286

Publication Date

12-1-2025

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