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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.


Quantitative analysis of lipid synthesis of microalgae under microbead compression.Black bar is a control and gray bar is a compressed sample. (a) Unicellular synthesis of lipid droplets with respect to compression times and compression levels. (b) Total synthesis of lipid droplets with respect to compression and times of compression.
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f5: Quantitative analysis of lipid synthesis of microalgae under microbead compression.Black bar is a control and gray bar is a compressed sample. (a) Unicellular synthesis of lipid droplets with respect to compression times and compression levels. (b) Total synthesis of lipid droplets with respect to compression and times of compression.

Mentions: The membrane distortion of microalgae induced by mechanical stress resulted in increased lipid accumulation in the cell81215. After subjecting cells to bead compression stress, qualitative and quantitative analysis was conducted every 4 hours to determine if lipid droplets occurred in the cell. As shown in Fig. 4a, lipid droplets were observed in compressed cells, starting at 4 h of compression, which was the minimum compression time required to induce lipid accumulation in C. reinhardtii (Supplementary Fig. S3). The lipid droplet size and number increased with compression times. In addition, the accumulation of lipid droplets according to compression levels was analyzed (Fig. 4b). Compression levels were controlled by a de-compression degree of syringe and the compression time was fixed for 12 h. Lipid droplets were observed up to the 6 ml de-compression degree. The size and number of lipid droplets was significantly decreased in 6–8 ml de-compression sample. Next, following the quantitative results by a sulpho-phospho-vanillin assay, the amount of lipids per unit of compressed cells was higher than that per unit of uncompressed cells in all de-compressed samples at 4–8 h of compression (Fig. 5a). However, 12 h of compression showed similar phenomena only in the 0 ml de-compression sample. Total lipid amount was also higher in compressed cells at all 4-12h of compression (Fig. 5b).


Mechanotransduction-Induced Lipid Production System with High Robustness and Controllability for Microalgae
Quantitative analysis of lipid synthesis of microalgae under microbead compression.Black bar is a control and gray bar is a compressed sample. (a) Unicellular synthesis of lipid droplets with respect to compression times and compression levels. (b) Total synthesis of lipid droplets with respect to compression and times of compression.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: Quantitative analysis of lipid synthesis of microalgae under microbead compression.Black bar is a control and gray bar is a compressed sample. (a) Unicellular synthesis of lipid droplets with respect to compression times and compression levels. (b) Total synthesis of lipid droplets with respect to compression and times of compression.
Mentions: The membrane distortion of microalgae induced by mechanical stress resulted in increased lipid accumulation in the cell81215. After subjecting cells to bead compression stress, qualitative and quantitative analysis was conducted every 4 hours to determine if lipid droplets occurred in the cell. As shown in Fig. 4a, lipid droplets were observed in compressed cells, starting at 4 h of compression, which was the minimum compression time required to induce lipid accumulation in C. reinhardtii (Supplementary Fig. S3). The lipid droplet size and number increased with compression times. In addition, the accumulation of lipid droplets according to compression levels was analyzed (Fig. 4b). Compression levels were controlled by a de-compression degree of syringe and the compression time was fixed for 12 h. Lipid droplets were observed up to the 6 ml de-compression degree. The size and number of lipid droplets was significantly decreased in 6–8 ml de-compression sample. Next, following the quantitative results by a sulpho-phospho-vanillin assay, the amount of lipids per unit of compressed cells was higher than that per unit of uncompressed cells in all de-compressed samples at 4–8 h of compression (Fig. 5a). However, 12 h of compression showed similar phenomena only in the 0 ml de-compression sample. Total lipid amount was also higher in compressed cells at all 4-12h of compression (Fig. 5b).

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.