scholarly journals Overexpression of Cu/Zn Superoxide Dismutase (Cu/Zn SOD) in Synechococcus elongatus PCC 7942 for Enhanced Azo Dye Removal through Hydrogen Peroxide Accumulation

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1313
Author(s):  
ShylajaNaciyar Mohandass ◽  
Mangalalakshmi Ragavan ◽  
Dineshbabu Gnanasekaran ◽  
Uma Lakshmanan ◽  
Prabaharan Dharmar ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Azo Dye ◽  
Dye Removal ◽  
Removal Rate ◽  
Synechococcus Elongatus ◽  
Survival Strategies ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Pcc 7942 ◽  
Derivative Strain

Discharge of recalcitrant azo dyes to the environment poses a serious threat to environmental health. However certain microorganisms in nature have developed their survival strategies by degrading these toxic dyes. Cyanobacteria are one such prokaryotic, photosynthetic group of microorganisms that degrade various xenobiotic compounds, due to their capability to produce various reactive oxygen species (ROS), and particularly the hydrogen peroxide (H2O2) when released in their milieu. The accumulation of H2O2 is the result of the dismutation of superoxide radicals by the enzyme superoxide dismutase (SOD). In this study, we have genetically modified the cyanobacterium Synechococcus elongatus PCC 7942 by integrating Cu/Zn SOD gene (sodC) from Synechococcus sp. PCC 9311 to its neutral site through homologous recombination. The overexpression of sodC in the derivative strain was driven using a strong constitutive promoter of the psbA gene. The derivative strain resulted in constitutive production of sodC, which was induced further during dye-treated growth. The genetically engineered Synechococcus elongatus PCC 7942 (MS-sodC+) over-accumulated H2O2 during azo dye treatment with a higher dye removal rate than the wild-type strain (WS-sodC−). Therefore, enhanced H2O2 accumulation through SODs overexpression in cyanobacteria may serve as a valuable bioremediation tool.

scholarly journals Assessment of Synechococcus elongatus PCC 7942 as an option for sustainable wastewater treatment

2021 ◽  
Author(s):  
Georgios Samiotis ◽  
Kostas Stamatakis ◽  
Elisavet Amanatidou
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Industrial Wastewater ◽  
Removal Rate ◽  
Synechococcus Elongatus ◽  
Green Energy ◽  
Dairy Wastewater ◽  
Biological Nutrient Removal ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Pcc 7942

Abstract Industrial wastewaters are recognized as a valuable resource, however their disposal without proper treatment can result in environmental deterioration. The associated environmental/operational cost of wastewater treatment necessitates upgrade of applied processes towards the goals of sustainability and mitigation of climate change. The implementation of cyanobacteria-based processes can contribute to these goals via resources recovery, production of high-value products, carbon fixation and green-energy production. The present study evaluates the cyanobacterium Synechococcus elongatus PCC 7942 (S7942) as a biological component for novel and sustainable alternatives to typical biological nutrient removal processes. Valuable results regarding cultivation temperature boundaries, applied disinfection techniques and analytical methods, as well as regarding relations between parameters expressing S7942 biomass concentration are presented. The results show that at typical industrial wastewater temperatures, S7942 efficiently grew and removed nitrates from treated snack-industry's wastewater. Moreover, in cultures with treated and relatively saline dairy wastewater, its growth rate slightly decreased, but nevertheless nitrates removal rate remained efficiently high. A comparison between typical denitrification processes and the proposed nutrient removal process indicated that a S7942-based system may constitute an alternative or a supplementary to denitrification process. Thus, Synechococcus elongatus PCC 7942 proved to be a potent candidate towards sustainable industrial wastewater treatment applications.

scholarly journals Photophysiological and Photosynthetic Complex Changes during Iron Starvation in Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942

PLoS ONE ◽  
2013 ◽  
Vol 8 (3) ◽  
pp. e59861 ◽  
Author(s):  
Jared M. Fraser ◽  
Sarah E. Tulk ◽  
Jennifer A. Jeans ◽  
Douglas A. Campbell ◽  
Thomas S. Bibby ◽  
...  
Keyword(s):  
Synechococcus Elongatus ◽  
Iron Starvation ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Pcc 7942 ◽  
Synechocystis Sp ◽  
Pcc 6803

Stability of the Synechococcus elongatus PCC 7942 circadian clock under directed anti-phase expression of the kai genes

Microbiology ◽  
2005 ◽  
Vol 151 (8) ◽  
pp. 2605-2613 ◽  
Author(s):  
Jayna L. Ditty ◽  
Shannon R. Canales ◽  
Breanne E. Anderson ◽  
Stanly B. Williams ◽  
Susan S. Golden
Keyword(s):  
Circadian Clock ◽  
Expression Patterns ◽  
Phase Relationship ◽  
Synechococcus Elongatus ◽  
Cycle Period ◽  
Rhythmic Expression ◽  
Core Components ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Time Required ◽  
Pcc 7942

The kaiA, kaiB and kaiC genes encode the core components of the cyanobacterial circadian clock in Synechococcus elongatus PCC 7942. Rhythmic expression patterns of kaiA and of the kaiBC operon normally peak in synchrony. In some mutants the relative timing of peaks (phase relationship) between these transcription units is altered, but circadian rhythms persist robustly. In this study, the importance of the transcriptional timing of kai genes was examined. Expressing either kaiA or kaiBC from a heterologous promoter whose peak expression occurs 12 h out of phase from the norm, and thus 12 h out of phase from the other kai locus, did not affect the time required for one cycle (period) or phase of the circadian rhythm, as measured by bioluminescence reporters. Furthermore, the data confirm that specific cis elements within the promoters of the kai genes are not necessary to sustain clock function.

scholarly journals Putative extracellular α-class carbonic anhydrase, EcaA, of Synechococcus elongatus PCC 7942 is an active enzyme: a sequel to an old story

Microbiology ◽  
2018 ◽  
Vol 164 (4) ◽  
pp. 576-586 ◽  
Author(s):  
Elena V. Kupriyanova ◽  
Maria A. Sinetova ◽  
Vladimir S. Bedbenov ◽  
Natalia A. Pronina ◽  
Dmitry A. Los
Keyword(s):  
Carbonic Anhydrase ◽  
Synechococcus Elongatus ◽  
Active Enzyme ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Pcc 7942

scholarly journals Role of KaiC phosphorylation in the circadian clock system of Synechococcus elongatus PCC 7942

2004 ◽  
Vol 101 (38) ◽  
pp. 13927-13932 ◽  
Author(s):  
T. Nishiwaki ◽  
Y. Satomi ◽  
M. Nakajima ◽  
C. Lee ◽  
R. Kiyohara ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Synechococcus Elongatus ◽  
Clock System ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Pcc 7942

Complete Replacement of the Galactolipid Biosynthesis Pathway with a Plant-Type Pathway in the Cyanobacterium Synechococcus elongatus PCC 7942

2020 ◽  
Vol 61 (9) ◽  
pp. 1661-1668
Author(s):  
Egi Tritya Apdila ◽  
Shukumi Inoue ◽  
Mie Shimojima ◽  
Koichiro Awai
Keyword(s):  
Chlorophyll Content ◽  
Membrane Lipids ◽  
Thylakoid Membranes ◽  
Synechococcus Elongatus ◽  
Biosynthesis Pathway ◽  
Plant Type ◽  
Complete Replacement ◽  
Essential Components ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Pcc 7942

Abstract Monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) are the major components of thylakoid membranes and well-conserved from cyanobacteria to chloroplasts. However, cyanobacteria and chloroplasts synthesize these galactolipids using different pathways and enzymes, but they are believed to share a common ancestor. This fact implies that there was a replacement of the cyanobacterial galactolipid biosynthesis pathway during the evolution of a chloroplast. In this study, we first replaced the cyanobacterial MGDG biosynthesis pathway in a model cyanobacterium, Synechococcus elongatus PCC 7942, with the corresponding plant-type pathway. No obvious phenotype was observed under the optimum growth condition, and the content of membrane lipids was not largely altered in the transformants. We next replaced the cyanobacterial DGDG biosynthesis pathway with the corresponding plant-type pathway using the strain described above and isolated the strain harboring the replaced plant-type pathway instead of the whole galactolipid biosynthesis pathway. This transformant, SeGPT, can grow photoautotrophically, indicating that cyanobacterial galactolipid biosynthesis pathways can be functionally complemented by the corresponding plant-type pathways and that the lipid products MGDG and DGDG, and not biosynthesis pathways, are important. While SeGPT does not show strong growth retardation, the strain has low cellular chlorophyll content but it retained a similar oxygen evolution rate per chlorophyll content compared with the wild type. An increase in total membrane lipid content was observed in SeGPT, which was caused by a significant increase in DGDG content. SeGPT accumulated carotenoids from the xanthophyll groups. These results suggest that cyanobacteria have the capacity to accept other pathways to synthesize essential components of thylakoid membranes.

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