Optimization of Recombinant Protein Production in Synechococcus elongatus PCC 7942: Utilizing Native Promoters and Magnetic Fields.

The cyanobacterium Synechococcus elongatus PCC 7942 holds significant potential as a biofactory for recombinant protein (RP) production due to its capacity to harness light energy and utilize CO2. This study aimed to enhance RP production by integration of native promoters and magnetic field application (MF) in S. elongatus PCC 7942. The psbA2 promoter, which responds to stress conditions, was chosen for the integration of the ZsGreen1 gene. Results indicated successful gene integration, affirming prior studies that showed no growth alterations in transgenic strains. Interestingly, exposure to 30 mT (MF30) demonstrated a increase in ZsGreen1 transcription under the psbA2 promoter, revealing the influence of MF on cyanobacterial photosynthetic machinery. This enhancement is likely attributed to stress-induced shifts in gene expression and enzyme activity. MF30 positively impacted photosystem II (PSII) without disrupting the electron transport chain, aligning with the "quantum-mechanical mechanism" theory. Notably, fluorescence levels and gene expression with application of 30 mT were significantly different from control conditions. This study showcases the efficacy of utilizing native promoters and MF for enhancing RP production in S. elongatus PCC 7942. Native promoters eliminate the need for costly exogenous inducers and potential cell stress. Moreover, the study expands the scope of optimizing RP production in photoautotrophic microorganisms, providing valuable insights for biotechnological applications.

Magnetic Fields as Inducers of Phycobiliprotein Production by Synechococcus elongatus PCC 7942.

This study aimed to analyze the effect of magnetic field (MF) application on the metabolism of Synechococcus elongatus PCC 7942. Concentrations of biomass, carbohydrate, protein, lipid, and photosynthetic pigments (chlorophyll-a, C-phycocyanin, allophycocyanin and phycoerythrin) were determined. In cultures with MF application (30 mT for 24 h d-1), there were increases of 47.5% in total protein content, 87.4% in C-phycocyanin, and 332.8% in allophycocyanin contents, by comparison with the control. Allophycocyanin is the most affected pigment by MF application. Therefore, its biosynthetic route was investigated, and four genes related to its synthesis were found. However, the analysis of the gene expression showed no statistical differences from the control culture, which suggests that induction of such genes may occur soon after MF application with consequent stabilization over time. MF application may be a cost-effective alternative to increase production of compounds of commercial interest by cyanobacteria.