Ethylene is a volatile alkene which is used in large commercial scale as a precursor in plastic industry, and is currently derived from petroleum refinement. As an alternative production strategy, photoautotrophic cyanobacteria Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 have been previously evaluated as potential biotechnological hosts for producing ethylene directly from CO, by the over-expression of ethylene forming enzyme (efe) from Pseudomonas syringae. This work addresses various open questions related to the use of Synechococcus as the engineering target, and demonstrates long-term ethylene production at rates reaching 140 µL L h OD without loss of host vitality or capacity to produce ethylene. The results imply that the genetic instability observed earlier may be associated with the expression strategies, rather than efe over-expression, ethylene toxicity or the depletion of 2-oxoglutarate-derived cellular precursors in Synechococcus. In context with literature, this study underlines the critical differences in expression system design in the alternative hosts, and confirms Synechococcus as a suitable parallel host for further engineering.
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http://dx.doi.org/10.1007/s11274-019-2652-7 | DOI Listing |
J Plant Res
December 2024
Graduate School of Science and Technology, Shizuoka University, Suruga-ku, Shizuoka, 422-8529, Japan.
Salinity and light markedly influence cyanobacterial viability. High salinity disrupts the osmotic balance, while excess light energy affects redox potential in the cells. Regulating the ratio of saturated and unsaturated alka(e)ne and fatty acids in cyanobacteria is thought to have crucial roles in coping with these stresses by regulating membrane fluidity.
View Article and Find Full Text PDFSci Rep
December 2024
Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
A circadian clock is reconstituted in vitro by incubating three proteins, KaiA, KaiB, and KaiC from the non-nitrogen-fixing cyanobacterium Synechococcus elongatus PCC 7942 in the presence of ATP. Leptolyngbya boryana is a filamentous cyanobacterium that grows diazotrophically under microoxic conditions. Among the aforementioned proteins, KaiC is the main clock oscillator belonging to the RecA ATPase superfamily.
View Article and Find Full Text PDFJ Biosci Bioeng
December 2024
Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan; Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan. Electronic address:
In bacteria, mechanosensitive channels mediate extracellular release of osmolytes, including glutamate, functioning as safety valves upon osmotic downshift. In cyanobacteria, the role of mechanosensitive channels has not been completely elucidated. Recently, the glycogen-deficient ΔglgC mutant of Synechococcus elongatus PCC 7942 was found to release glutamate extracellularly, giving rise to a hypothesis that the role of mechanosensitive channels in cyanobacteria is conserved.
View Article and Find Full Text PDFJ Biol Chem
December 2024
School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China. Electronic address:
Base editing is preferable for bacterial gene inactivation without generating double strand breaks, requiring homology recombination or highly efficient DNA delivery capability. However, the potential of base editing is limited by the adjoined dependence on the editing window and protospacer adjacent motif (PAM). Herein, we report an unconstrained base editing system to enable the inactivation of any genes of interest (GOIs) in bacteria.
View Article and Find Full Text PDFFront Microbiol
December 2024
Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, United States.
Introduction: (), one of the most prevalent blue-green algae in aquatic environments, produces microcystin by causing harmful algal blooms (HAB). This study investigated the combined effects of nutrients and cyanobacterial subpopulation competition on synthesizing microcystin-LR.
Method: In varied nitrogen and phosphorus concentrations, cyanobacterial coculture, and algicidal DCMU presence, the growth was monitored by optical density analysis or microscopic counting, and the microcystin production was analyzed using high-performance liquid chromatography-UV.
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