The phototrophic purple non‐sulfur bacteria Rhodomicrobium spp. are novel chassis for bioplastic production
Year: 2024
Type: article
Abstract: Petroleum‐based plastics levy significant environmental and economic costs that can be alleviated with sustainably sourced, biodegradable, and bio‐based polymers such as polyhydroxyalkanoates (PHAs). However, industrial‐scale production of PHAs faces barriers stemming from insufficient product yields and high costs. To address these challenges, we must look beyond the current suite of microbes for PHA production and investigate non‐model organisms with versatile metabolisms. In that vein, we assessed PHA production by the photosynthetic purple non‐sulfur bacteria (PNSB) Rhodomicrobium vannielii and Rhodomicrobium udaipurense. We show that both species accumulate PHA across photo‐heterotrophic, photo‐hydrogenotrophic, photo‐ferrotrophic, and photo‐electrotrophic growth conditions, with either ammonium chloride (NH 4 Cl) or dinitrogen gas (N 2 ) as nitrogen sources. Our data indicate that nitrogen source plays a significant role in dictating PHA synthesis, with N 2 fixation promoting PHA production during photoheterotrophy and photoelectrotrophy but inhibiting production during photohydrogenotrophy and photoferrotrophy. We observed the highest PHA titres (up to 44.08 mg/L, or 43.61% cell dry weight) when cells were grown photoheterotrophically on sodium butyrate with N 2 , while production was at its lowest during photoelectrotrophy (as low as 0.04 mg/L, or 0.16% cell dry weight). We also find that photohydrogenotrophically grown cells supplemented with NH 4 Cl exhibit the highest electron yields – up to 58.89% – while photoheterotrophy demonstrated the lowest (0.27%–1.39%). Finally, we highlight superior electron conversion and PHA production compared to a related PNSB, Rhodopseudomonas palustris TIE‐1. This study illustrates the value of studying non‐model organisms like Rhodomicrobium for sustainable PHA production and indicates future directions for exploring PNSB metabolisms.
Source: Microbial Biotechnology
Institution: Washington University in St. Louis
Language: English
Subfield: Biomaterials
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,700
Funders: National Science Foundation, U.S. Department of Defense, David and Lucile Packard Foundation, U.S. Department of Energy, Gordon and Betty Moore Foundation, Washington University in St. Louis, National Institute for Health and Care Research, International Center for Energy, Environment and Sustainability, Washington University in St. Louis, National Institute of General Medical Sciences, Lawrence Livermore National Laboratory
Awards: G1285901844, G1476449348, Investigating the metabolic cooperation between a phototrophic bacterium and a methanogenic archaeon, G2221269905, Planning Grant: Engineering Research Center for Electrosymbiotic Engineering, Design, and Technology (CEED-TECH), G3381768330, G4241921286, (DEPSCOR) UNDERSTANDING THE ROLE OF MICROBIAL EXTRACELLULAR ELECTRON UPTAKE IN HUMAN PATHOGENS USING MULTI-MODAL MICROFLUIDICS, G4326084593, G5410917386, EXPANDING OUR UNDERSTANDING OF HOW MICROBES INTERACT WITH CHARGED SURFACES, G6368956742, DEVELOPMENT OF A NOVEL HIGH PRECISION HIGH‐RESOLUTION SIMS PLATFORM FOR ELEMENTAL AND ISOTOPIC CHA, MRI: Acquisition of a Laboratory-Based X-ray Absorption and Emission Spectroscopy Instrument, G7016916515, Sustainable bioproduction using phototrophic extracellular electron uptake, G8799031779
OpenAlex ID: W4401729234