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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.


Optimization of elastic microbeads used to induce mechanotransduction of microalgae.The effects of PU density on (a) microbead morphology and (b) size. (c) SEM images of porous microbead surface and (d) inside of the microbead. The density of the PU beads was 30% (w/v) of the PU concentration.
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f2: Optimization of elastic microbeads used to induce mechanotransduction of microalgae.The effects of PU density on (a) microbead morphology and (b) size. (c) SEM images of porous microbead surface and (d) inside of the microbead. The density of the PU beads was 30% (w/v) of the PU concentration.

Mentions: The MDLP system was designed by applying the principle of mechanotransduction that the lipid accumulation was induced by membrane distortion of the cell, and then fabricated to induce the organic conversion of microalgae (Fig. 1). When the compressed beads and microalgae were mixed in the reactor, the inflated beads occupied the pre-vacant space, which transmitted compressive force to cells equally via the spatial dispersion of the force. Operation of the prototype device was confirmed based on the finding that it went through the successful process of compression, inoculation, de-compression and harvest step. About 60 × 106 cells were seeded in one cycle of process. If cell is pre-seeded and compressed, lots of cells would be expelled with the media. This is why the beads were first compressed and then, cells were seeded and compressed by the inflating bead force. The spherical and elastic polyurethane beads became distorted by the compression force and were restored by absorbing surrounding media. SEM images were analyzed to understand the physical properties of this PU bead. As shown in Fig. 2c, there were countless microscopic pores on the surfaces of the beads, which allowed liquids to enter and exit the pores of the beads. There were also empty spaces within the bead that could absorb a certain amount of liquid. These findings confirmed that the prototype of the device could actualize the process shown in Supplementary Fig. S1.


Mechanotransduction-Induced Lipid Production System with High Robustness and Controllability for Microalgae
Optimization of elastic microbeads used to induce mechanotransduction of microalgae.The effects of PU density on (a) microbead morphology and (b) size. (c) SEM images of porous microbead surface and (d) inside of the microbead. The density of the PU beads was 30% (w/v) of the PU concentration.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Optimization of elastic microbeads used to induce mechanotransduction of microalgae.The effects of PU density on (a) microbead morphology and (b) size. (c) SEM images of porous microbead surface and (d) inside of the microbead. The density of the PU beads was 30% (w/v) of the PU concentration.
Mentions: The MDLP system was designed by applying the principle of mechanotransduction that the lipid accumulation was induced by membrane distortion of the cell, and then fabricated to induce the organic conversion of microalgae (Fig. 1). When the compressed beads and microalgae were mixed in the reactor, the inflated beads occupied the pre-vacant space, which transmitted compressive force to cells equally via the spatial dispersion of the force. Operation of the prototype device was confirmed based on the finding that it went through the successful process of compression, inoculation, de-compression and harvest step. About 60 × 106 cells were seeded in one cycle of process. If cell is pre-seeded and compressed, lots of cells would be expelled with the media. This is why the beads were first compressed and then, cells were seeded and compressed by the inflating bead force. The spherical and elastic polyurethane beads became distorted by the compression force and were restored by absorbing surrounding media. SEM images were analyzed to understand the physical properties of this PU bead. As shown in Fig. 2c, there were countless microscopic pores on the surfaces of the beads, which allowed liquids to enter and exit the pores of the beads. There were also empty spaces within the bead that could absorb a certain amount of liquid. These findings confirmed that the prototype of the device could actualize the process shown in Supplementary Fig. S1.

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.