Ideal Microbe for Industrial Purposes

Released: February 06, 2015
Strain has highest growth rate to date of any cyanobacteria
This study identified a novel cyanobacterial strain that grows rapidly and is amenable to genetic manipulation—qualities that make this organism suitable for a wide range of synthetic biology and metabolic engineering applications.

The Science

Cyanobacteria are of considerable interest as production organisms in biotechnology. They can grow by harvesting energy from sunlight, an abundant energy source, and they consume carbon dioxide, a greenhouse gas. However, commonly used cyanobacterial strains grow slow. Furthermore their genetic and metabolic networks are not as well understood when compared with other bacteria and yeast models used for industrial applications. This study identified a novel cyanobacterial strain that grows rapidly and is amenable to genetic manipulation that makes it ideal for a wide range of synthetic biology and metabolic engineering applications.

The Impact

A cyanobacterial strain that can grow rapidly and is amenable to easy, targeted genetic manipulation will expedite the process of characterizing the cellular biology and genetic and metabolic networks of cyanobacteria. The strain will also enable development of new synthetic biology tools for these microbes. The newly identified strain could pave the way for widespread use of cyanobacteria for carbon sequestration, biofuel production, biosynthesis of valuable chemicals, and search for novel pharmaceuticals.

Summary

In search for an ideal photosynthetic microbe for industrial purposes, researchers from Washington University in St. Louis, Pacific Northwest National Laboratory (PNNL), EMSL, the Environmental Molecular Sciences Laboratory and the University of Texas at Austin identified a fast growing cyanobacterial strain called Synechococcus elongatus UTEX 2973. To characterize this strain, they performed whole-genome sequencing at WUSTL and proteomics at EMSL, a DOE national scientific user facility.

The researchers found the newly identified strain grows as fast as yeast, without requiring special nutrients such as vitamins. Its growth rate is not only the highest reported to date for any cyanobacterium strain, but is also more than twice as fast as a widely studied close relative. As a result, Synechococcus UTEX 2973 rapidly accumulated substantial amounts of biomass—a valuable trait in the bioenergy arena. The rapid growth of this cyanobacterial strain also facilitates genetic manipulation studies. The researchers generated two types of mutants by introducing a gene encoding a fluorescent protein and inactivating a gene involved in the regulation of light harvesting, demonstrating the newly described strain is amenable to easy, rapid genetic modification.

The genome sequencing data showed a small number of nucleotide changes are the only significant differences between the genomes of the two closely related cyanobacterial strains, which are 99.8 percent identical in their genome sequences. These findings revealed the genetic determinants necessary for rapid growth of cyanobacterial strains of significant industrial potential. Moreover, the proteomics data will be a valuable resource for the research community because the global proteomes of the two cyanobacterial strains had never before been analyzed. Taken together, the findings demonstrate the excellent potential of Synechococcus UTEX 2973 as a cyanobacterial strain for broad biotechnological applications.

Contacts: Himadri Pakrasi, pakrasi@wustl.edu and David Koppenaal, david.koppenaal@pnnl.gov.

Funding: DOE Office of Science’s Office of Biological and Environmental Research, the National Science Foundation and the EMSL Synthetic Biology Research Campaign

Publication: Yu, J, M Liberton, PF Cliften, RD Head, JM Jacobs, RD Smith, DW Koppenaal, JJ Brand, and HB Pakrasi. 2015. “Synechococcus elongatus UTEX 2973, a fast growing cyanobacterial chassis for biosynthesis using light and CO2.” Scientific Reports 5:8132. DOI:10.1038/srep08132.

Program: DOE Office of Science’s Office of Biological and Environmental Research

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