Tailor‐made PAT platform for safe syngas fermentations in batch, fed‐batch and chemostat mode with Rhodospirillum rubrum

• Published in: Microbial biotechnology 2017-11, Vol.10 (6), p.1365-1375
• Main Authors: Karmann, Stephanie, Follonier, Stéphanie, Egger, Daniel, Hebel, Dirk, Panke, Sven, Zinn, Manfred
• Format: Article
• Language: English
• Subjects: Analytical methods; Bacteria; Batch Cell Culture Techniques - instrumentation; Batch Cell Culture Techniques - methods; Biocompatibility; Biodegradability; Biodegradation; Biomass; Bioreactors - microbiology; Calibration; Carbon dioxide; Carbon Dioxide - chemistry; Carbon Dioxide - metabolism; Carbon monoxide; Carbon Monoxide - chemistry; Carbon Monoxide - metabolism; Catalysis; Cell culture; Consumption; Fermentation; Gas analysis; Gases; Hazards; Hydrogen - chemistry; Hydrogen - metabolism; Hydroxybutyrates - chemistry; Hydroxybutyrates - metabolism; Internet; Kinetics; Laboratories; Polyesters - chemistry; Polyesters - metabolism; Polyhydroxybutyrate; Quadrupoles; Rhodospirillum rubrum; Rhodospirillum rubrum - chemistry; Rhodospirillum rubrum - metabolism; Software; Sulfur; Synthesis gas; Technology assessment; Toxicity
• ISSN: 1751-7915; 1751-7915
• DOI: 10.1111/1751-7915.12727

Summary Recently, syngas has gained significant interest as renewable and sustainable feedstock, in particular for the biotechnological production of poly([R]‐3‐hydroxybutyrate) (PHB). PHB is a biodegradable, biocompatible polyester produced by some bacteria growing on the principal component of syngas, CO. However, working with syngas is challenging because of the CO toxicity and the explosion danger of H2, another main component of syngas. In addition, the bioprocess control needs specific monitoring tools and analytical methods that differ from standard fermentations. Here, we present a syngas fermentation platform with a focus on safety installations and process analytical technology (PAT) that serves as a basis to assess the physiology of the PHB‐producing bacterium Rhodospirillum rubrum. The platform includes (i) off‐gas analysis with an online quadrupole mass spectrometer to measure CO consumption and production rates of H2 and CO2, (ii) an at‐line flow cytometer to determine the total cell count and the intracellular PHB content and (iii) different online sensors, notably a redox sensor that is important to confirm that the culture conditions are suitable for the CO metabolization of R. rubrum. Furthermore, we present as first applications of the platform a fed‐batch and a chemostat process with R. rubrum for PHB production from syngas. The utilization of syngas as a gaseous substrate for the production of biodegradable plastics requires excellent monitoring of the bioprocess for research and safety reasons. The performance of the syngas fermentation platform is documented by the presentation of fed‐batch and chemostat experiments carried out with Rhodospirillum rubrum.