Abstract
Bacterial synthesis of polyhydroxybutyrates (PHBs) is a potential approach for producing biodegradable plastics. This study assessed the ability of Rhodopseudomonas palustris TIE-1 to produce PHBs under various conditions. We focused on photoautotrophy using a poised electrode (photoelectroautotrophy) or ferrous iron (photoferroautotrophy) as electron donors. Growth conditions were tested with either ammonium chloride or dinitrogen gas as the nitrogen source. Although TIE-1’s capacity to produce PHBs varied fairly under different conditions, photoelectroautotrophy and photoferroautotrophy showed the highest PHB electron yield and the highest specific PHB productivity, respectively. Gene expression analysis showed that there was no differential expression in PHB biosynthesis genes. This suggests that the variations in PHB accumulation might be post-transcriptionally regulated. This is the first study to systematically quantify the amount of PHB produced by a microbe via photoelectroautotrophy and photoferroautotrophy. This work could lead to sustainable bioproduction using abundant resources such as light, electricity, iron, and carbon dioxide.
Highlights
Polyhydroxybutyrates (PHBs) are the most well-studied members of the polyhydroxyalkanoates (PHAs), which is a family of biodegradable intracellular polyesters produced by several bacteria [38, 45, 67, 79, 85]
TIE-1 grown under sodium butyrate, Fe(II)–nitrilotriacetic acid (NTA) and poised graphite electrode was used as representative samples for STEM-EELS
Localized PHB granules were characterized using a JEOL JEM-2100F field emission scanning transmission electron microscopy (FE-STEM) with an accelerating voltage of 200 keV (Institute of Material Science and Engineering, WUSTL); the microscope is attached with a Gatan BF/DF detector, Gatan HAADF detector and Gatan 863 Tridiem imaging filter (GIF) system
Summary
Polyhydroxybutyrates (PHBs) are the most well-studied members of the polyhydroxyalkanoates (PHAs), which is a family of biodegradable intracellular polyesters produced by several bacteria [38, 45, 67, 79, 85]. Heterotrophic microbes can be promising PHB producers as they can use low-cost carbon sources including. The requirement for a continuous supply of food wastes makes them an infeasible source of carbon. Lignocellulose from food [54] and forestry industries [41] or glycerol wastes from biofuel production have been explored in heterotrophic PHB production [4, 75]. Due to the requirement of arable land, and direct competition with human food consumption, using these substrates for PHB production is not desirable [17]. These potential limitations of using heterotrophs eventually led to the investigation of autotrophs for PHB production [38]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Industrial Microbiology and Biotechnology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
