Engineering cyanobacterial chassis for improved electron supply toward a heterologous ene-reductase

Jelena Spasic, Paulo Oliveira, Catarina Pacheco, Robert Kourist, Paula Tamagnini*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Cyanobacteria are noteworthy hosts for industrially relevant redox reactions, owing to a light-driven cofactor recycling system using water as electron donor. Customizing Synechocystis sp. PCC 6803 chassis by redirecting electron flow offers a particularly interesting approach to further improve light-driven biotransformations. Therefore, different chassis expressing the heterologous ene-reductase YqjM (namely ΔhoxYH, Δflv3, ΔndhD2 and ΔhoxYHΔflv3) were generated/evaluated. The results showed the robustness of the chassis, that exhibited growth and oxygen evolution rates similar to Synechocystis wild-type, even when expressing YqjM. By engineering the electron flow, the YqjM light-driven stereoselective reduction of 2-methylmaleimide to 2-methylsuccinimide was significantly enhanced in all chassis. In the best performing chassis (ΔhoxYH, lacking an active bidirectional hydrogenase) a 39 % increase was observed, reaching an in vivo specific activity of 116 U gDCW−1 and an initial reaction rate of 16.7 mM h−1. In addition, the presence of the heterologous YqjM mitigated substrate toxicity, and the conversion of 2-methylmaleimide increased oxygen evolution rates, in particular at higher light intensity. In conclusion, this work demonstrates that rational engineering of electron transfer pathways is a valid strategy to increase in vivo specific activities and initial reaction rates in cyanobacterial chassis harboring oxidoreductases.

Original languageEnglish
Pages (from-to)152-159
Number of pages8
JournalJournal of Biotechnology
Publication statusPublished - 10 Dec 2022


  • Biocatalysis
  • Biotransformation
  • Cyanobacteria
  • Synechocystis
  • Synthetic biology

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology


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