The research group aims in developing so far under-explored bacteria as novel platform organisms for applications in biotechnology and biocatalysis. The major focus is on applied microbiology with photosynthetic purple bacteria. The extraordinary metabolic flexibility makes these microorganisms an outstanding source for various valuable compounds such as anti-tumor compounds, recombinant membrane proteins, terpenoids, biopolymers, vitamins, biohydrogen and others. Based on a novel cultivation process with full expression of photosynthetic genes, completely independent of light, under microaerobic conditions in the dark, it is now possible to exploit the full metabolic potential, normally available only under photosynthetic conditions, thereby facilitating applications requiring large-scale cultures.

In order to meet the needs of current bioeconomy concepts, the bioprocesses are developed using industrial waste streams as substrates for large-scale cultivation.

In addition, enzymes obtained from the bacteria are currently used for developing biocatalytic systems for the conversion of CO2 to value-added products.

The individual projects are highly interdisciplinary cooperative projects with external partners, following a systems biology approach with a strong impact of computational modeling.

Current group members are at the Postdoc or M.Sc. level as well and lab-technicians. We also regularly host students for their Bachelor or Master theses.

Projects in overview:

Institute members


Lab technician


Kay Bretz

Carina Dietz


Sarah Leibinger

Scientific publications

  • Witt A, Pozzi R, Diesch S, Hädicke O, Grammel H. 2019. New light on ancient enzymes – in vitro CO2 fixation by pyruvate synthase of Desulfovibrio africanus and Sulfolobus acidocaldarius. FEBS J. 286(22):4494-4508. doi: 10.1111/febs.14981.
  • Carius L, Rumschinski P, Faulwasser T, Flockerzi D, Grammel H, and R. Findeisen. 2014. Model-based derivation, analysis and control of unstable microaerobic steady-states - considering Rhodospirillum rubrum as an example. Biotechnol Bioeng. 111(4):734-47
  • Carius L, Carius AB, McIntosh M, and H. Grammel. 2013. Quorum sensing influences growth and photosynthetic membrane production in high-cell-density cultivations of Rhodospirillum rubrum. BMC Microbiol. 13:189.
  • Carius L, Hädicke O, and H. Grammel. 2013. Stepwise reduction of the culture redox potential allows the analysis of microaerobic metabolism and photosynthetic membrane synthesis in Rhodospirillum rubrum. Biotechnol Bioeng. 110(2):573-85.
  • Wang, G-S., H. Grammel, K. Abou-Aisha, R. Saegesser, and R. Ghosh. 2012. High-level production of the industrial product, lycopene, using the photosynthetic bacterium Rhodospirillum rubrum. Appl. Env. Microbiol.78(20):7205-15.
  • Rudolf, C., and H. Grammel. 2012. Fructose metabolism of the purple non-sulfur bacterium Rhodospirillum rubrum: Effect of carbon dioxide on growth, and production of bacteriochlorophyll and organic acids. Enzyme Microb Technol. 50:238-246.
  • Franz, A., R. Rehner, A. Kienle, and H. Grammel. 2012. Rapid selection of glucose-utilizing variants of the polyhydroxyalkanoate producer Ralstonia eutropha H16 by incubation with high substrate levels. Lett. Appl. Microbiol. 54(1):45-51.

Conference talks

  • Grammel, H. Sustainable in vitro Enzymatic CO2 Fixation Including Chloroplast-driven Energy and Redox Cofactor Recycling. 3rd International Bioeconomy Congress Baden-Württemberg – Online. 21 - 22 September 2020
  • Grammel, H. Archaische Enzyme in neuem Licht - in vitro CO2 -Fixierung
  • mit Pyruvat-Synthase. 19. Heiligenstädter Kolloquium. 24.09. - 26.09.2018. Heilbad Heiligenstadt, Germany
  • Grammel, H. Systembiologische Untersuchung bakterieller Stoffwechselnetzwerke und Enzyme für die technische Verwertung von CO2. 18. Heiligenstädter Kolloquium. 19.09. - 21.09.2016. Heilbad Heiligenstadt, Germany
  • Grammel, H. Untersuchung bakterieller Stoffwechselnetzwerke und Enzyme zur biotechnologischen Verwertung von CO2. Jahrestagung  der  Forschungsorganisationen  zum  Strategieprozess  Biotechnologie  2020+. September 22-23, 2015. Berlin, Germany
  • Grammel, H. Perspectives of Applied Microbiology with Purple Bacteria Driven by Systems Biology. BioTech2014. June 11 – 14, 2014, Prague, Czech Republic
  • Grammel, H. Microaerobic Monitoring and Control for Industrial Applications of Photosynthetic Bacteria. BIT’s 4th World Gene Convention-2013, November 13-16, Haikou, China
  • Grammel, H. Perspectives of Applied Microbiology with Purple Bacteria Driven by Systems Biology. Global Biotechnology Congress 2013. June 3rd – 6th, 2013, Boston, USA
  • Grammel, H. 2012. Analyse und Design bakterieller Enzymkaskaden zur stofflichen Verwertung von CO2. BMBF Kick-off Seminar Fördermaßnahme Basistechnologien, Berlin, Germany
  • Grammel, H. 2012. Perspektiven der Angewandten Mikrobiologie mit Purpurbakterien. Forum Biotechnologie, Freiburg, Germany

Analyse und Design bakterieller Enzymkaskaden zur stofflichen Verwertung von CO2

EnzCaps„Entwicklung einer neuen Technologie: Eingekapselte synthetische Multienzymsysteme für Multischritt-Reaktionen in Anwesenheit von organischen Lösungsmitteln: ein systematischer Ansatz“

„Purple Synthetic Biology” N-Quellen regulierte Produktion von einem zwei-Schritt katalysierenden Enzymkomplex in Rhodospirillum rubrum

  • Funding: Fördermaßnahme „Biotechnologie 2020plus - Basistechnologien für eine nächste Generation biotechnologischer Verfahren“, BMBF

ChiC-Polymers - Maßgeschneiderte Biopolymere durch molekulares Design von Nanocellulose-synthetisierenden Bakterien

  • Funding: Ideenwettbewerb Biotechnologie, Land Baden-Württemberg