Skip to main content

Advertisement

Log in

Isobutanol production as an alternative metabolic sink to rescue the growth deficiency of the glycogen mutant of Synechococcus elongatus PCC 7942

  • Regular Paper
  • Published:
Photosynthesis Research Aims and scope Submit manuscript

Abstract

Glycogen synthesis initiated by glucose-1-phosphate adenylyltransferase (glgC) represents a major carbon storage route in cyanobacteria which could divert a significant portion of assimilated carbon. Significant growth retardation in cyanobacteria with glgC knocked out (ΔglgC) has been reported in high light conditions. Here, we knocked out the glgC gene and analyzed its effects on carbon distribution in an isobutanol-producing strain of Synechococcus elongatus PCC7942 and its parental wild-type strain. We showed that isobutanol production was able to partially rescue the growth of ΔglgC mutant where the growth rescue effect positively correlated with the rate of isobutanol production. Using NaH14CO3 incorporation analysis, we observed a 28 % loss of total carbon fixation rate in the ΔglgC mutant compared to the wild-type. Upon expression of the isobutanol production pathway in ΔglgC mutant, the total carbon fixation rate was restored to the wild-type level. Furthermore, we showed that 52 % of the total carbon fixed was redirected into isobutanol biosynthesis in the ΔglgC mutant expressing enzymes for isobutanol production, which is 2.5 times higher than that of the wild-type expressing the same enzymes. These results suggest that biosynthesis of non-native product such as isobutanol can serve as a metabolic sink for replacing glycogen to rescue growth and restore carbon fixation rate. The rescue effect may further serve as a platform for cyanobacteria energy and carbon metabolism study.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

Similar content being viewed by others

References

Download references

Acknowledgments

The authors would like to thank Ethan I. Lan for the plasmids and valuable discussions. This work is supported by PETRO program of the Advanced Research Projects Agency–Energy (ARPA-E) of DOE (Award number DE-AR0000201). This project is also partially supported by NSF MCB-1139318 and UCLA-DOE Institute for Genomics and Proteomics.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to James C. Liao.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary material 1 (DOCX 675 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Li, X., Shen, C.R. & Liao, J.C. Isobutanol production as an alternative metabolic sink to rescue the growth deficiency of the glycogen mutant of Synechococcus elongatus PCC 7942. Photosynth Res 120, 301–310 (2014). https://doi.org/10.1007/s11120-014-9987-6

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11120-014-9987-6

Keywords

Navigation