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Mechanotransduction-Induced Lipid Production System with High Robustness and Controllability for Microalgae

View Article: PubMed Central - PubMed

ABSTRACT

Microalgae lipids are a promising energy source, but current biochemical methods of lipid-inductions such as nitrogen deprivation have low process robustness and controllability. Recently, use of mechanotransduction based membrane distortion by applying compression stress in a 2D-microsystem was suggested as a way to overcome these limitations of biochemical induction. However, reproduction in large numbers of cells without cell death has been difficult to overcome because compression for direct membrane distortion reduces culture volume and leads to cell death due to nutrient deprivation. In this study, a mechanotransduction-induced lipid production (MDLP) system that redirects elastic microbeads to induce membrane distortion of microalgae with alleviating cell death was developed. This system resulted in accumulation of lipid in as little as 4 hr. Once compressed, porous microbeads absorb media and swell simultaneously while homogeneously inducing compression stress of microalgae. The absorbed media within beads could be supplied to adjacent cells and could minimize cell death from nutrient deficiency. All mechanotransduction was confirmed by measuring upregulation of calcium influx and Mat3 genes. The microbeads ensured robustness and controllability in repeated compression/de-compression processes. Overall, the MDLP system has potential for use as a fundamental biodiesel process that requires robustness and controllability.

No MeSH data available.


Verification of microbeads-induced mechanotransduction in view of calcium influx, deflagellation and cell size.Bead compression invoked (a) deflagellation and (b) calcium influx to microalgae. Bead compression decreased (c) microalgal size and increased (d) its associated gene, Mat3. T-test of P values was conducted according to control and compression (*P < 5.0×10−2, **P < 1.0×10−2, ***P < 1.0×10−3).
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f3: Verification of microbeads-induced mechanotransduction in view of calcium influx, deflagellation and cell size.Bead compression invoked (a) deflagellation and (b) calcium influx to microalgae. Bead compression decreased (c) microalgal size and increased (d) its associated gene, Mat3. T-test of P values was conducted according to control and compression (*P < 5.0×10−2, **P < 1.0×10−2, ***P < 1.0×10−3).

Mentions: C. reinhardtii was deflagellated by bead compression stress and the Ca2+ influx was greater in the compressed cell than the control cell. (Supplementary Fig. S2 and Fig. 3a,b). The size of compressed cells harvested from the device was compared with that of control cells (Fig. 3c). The results showed that the average size of the compressed cells decreased relative to the control cells. In the case of cells that were compressed for 12 hours, the largest cell diameter was 7.2 μm. At less than 7.2 μm, the compressed cells showed greater distribution than the control cells. After compression for 24 hours, the uncompressed and the compressed cell had a maximum size at 7.8 μm and 6.7 μm, respectively. The overall compressed cell diameter decreased by 0.5 to 1 μm compared with the uncompressed cells. Based on these results, bead compression stress induced membrane distortion, followed by increased Ca2+ influx into the cell, deflagellation, and small cell size. The mRNA of Mat3 and E2F1 were related to these physiological changes14. As shown in Fig. 3d, Mat3 mRNA was upregulated in all compression samples, while there was no tendency to upregulate in E2F1 mRNA.


Mechanotransduction-Induced Lipid Production System with High Robustness and Controllability for Microalgae
Verification of microbeads-induced mechanotransduction in view of calcium influx, deflagellation and cell size.Bead compression invoked (a) deflagellation and (b) calcium influx to microalgae. Bead compression decreased (c) microalgal size and increased (d) its associated gene, Mat3. T-test of P values was conducted according to control and compression (*P < 5.0×10−2, **P < 1.0×10−2, ***P < 1.0×10−3).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5016897&req=5

f3: Verification of microbeads-induced mechanotransduction in view of calcium influx, deflagellation and cell size.Bead compression invoked (a) deflagellation and (b) calcium influx to microalgae. Bead compression decreased (c) microalgal size and increased (d) its associated gene, Mat3. T-test of P values was conducted according to control and compression (*P < 5.0×10−2, **P < 1.0×10−2, ***P < 1.0×10−3).
Mentions: C. reinhardtii was deflagellated by bead compression stress and the Ca2+ influx was greater in the compressed cell than the control cell. (Supplementary Fig. S2 and Fig. 3a,b). The size of compressed cells harvested from the device was compared with that of control cells (Fig. 3c). The results showed that the average size of the compressed cells decreased relative to the control cells. In the case of cells that were compressed for 12 hours, the largest cell diameter was 7.2 μm. At less than 7.2 μm, the compressed cells showed greater distribution than the control cells. After compression for 24 hours, the uncompressed and the compressed cell had a maximum size at 7.8 μm and 6.7 μm, respectively. The overall compressed cell diameter decreased by 0.5 to 1 μm compared with the uncompressed cells. Based on these results, bead compression stress induced membrane distortion, followed by increased Ca2+ influx into the cell, deflagellation, and small cell size. The mRNA of Mat3 and E2F1 were related to these physiological changes14. As shown in Fig. 3d, Mat3 mRNA was upregulated in all compression samples, while there was no tendency to upregulate in E2F1 mRNA.

View Article: PubMed Central - PubMed

ABSTRACT

Microalgae lipids are a promising energy source, but current biochemical methods of lipid-inductions such as nitrogen deprivation have low process robustness and controllability. Recently, use of mechanotransduction based membrane distortion by applying compression stress in a 2D-microsystem was suggested as a way to overcome these limitations of biochemical induction. However, reproduction in large numbers of cells without cell death has been difficult to overcome because compression for direct membrane distortion reduces culture volume and leads to cell death due to nutrient deprivation. In this study, a mechanotransduction-induced lipid production (MDLP) system that redirects elastic microbeads to induce membrane distortion of microalgae with alleviating cell death was developed. This system resulted in accumulation of lipid in as little as 4&thinsp;hr. Once compressed, porous microbeads absorb media and swell simultaneously while homogeneously inducing compression stress of microalgae. The absorbed media within beads could be supplied to adjacent cells and could minimize cell death from nutrient deficiency. All mechanotransduction was confirmed by measuring upregulation of calcium influx and Mat3 genes. The microbeads ensured robustness and controllability in repeated compression/de-compression processes. Overall, the MDLP system has potential for use as a fundamental biodiesel process that requires robustness and controllability.

No MeSH data available.