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Enhancement of glycerol metabolism in the oleaginous marine diatom Fistulifera solaris JPCC DA0580 to improve triacylglycerol productivity.

Muto M, Tanaka M, Liang Y, Yoshino T, Matsumoto M, Tanaka T - Biotechnol Biofuels (2015)

Bottom Line: Overexpression of the endogenous glycerol kinase (GK) gene in an oleaginous marine diatom, Fistulifera solaris JPCC DA0580, accelerates glycerol metabolism and improves lipid and biomass productivities.We have demonstrated the potential of metabolic engineering in oleaginous microalgae to improve lipid productivity.Metabolic engineering techniques can be used to optimize BDF production.

View Article: PubMed Central - PubMed

Affiliation: Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 Japan ; JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075 Japan.

ABSTRACT

Background: Microalgal oil is a promising alternative feedstock for biodiesel fuel (BDF). Mixotrophic cultivation with glycerol, the primary byproduct of BDF production, may be used to optimize BDF production. This strategy would reduce costs through glycerol recycling and improve lipid productivity and biomass productivity by overcoming the growth retardation caused by decreased light penetration in high-density culture.

Results: Overexpression of the endogenous glycerol kinase (GK) gene in an oleaginous marine diatom, Fistulifera solaris JPCC DA0580, accelerates glycerol metabolism and improves lipid and biomass productivities. Two candidates were selected from a collection of 90 G418-resistant clones, based on growth and confirmation of genome integration. GK gene expression was higher in the selected clones (GK1_7 and GK2_16) than in the wild-type culture. The GK2_16 clone achieved a 12% increase in lipid productivity.

Conclusion: We have demonstrated the potential of metabolic engineering in oleaginous microalgae to improve lipid productivity. Metabolic engineering techniques can be used to optimize BDF production.

No MeSH data available.


Related in: MedlinePlus

Relative mRNA abundance in the wild-type and glycerol kinase (GK) gene transformants. Gene expression was evaluated in the GK1_7 (A) and GK2_16 (B) transformants, with housekeeping genes rps and Ub as controls.
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Fig3: Relative mRNA abundance in the wild-type and glycerol kinase (GK) gene transformants. Gene expression was evaluated in the GK1_7 (A) and GK2_16 (B) transformants, with housekeeping genes rps and Ub as controls.

Mentions: GK expression levels in GK1_7 and GK2_16 clones were examined by quantitative reverse transcription PCR (qRT-PCR), with housekeeping genes ribosomal protein subunit (rps) and ubiquitin (Ub) as controls (Figure 3). The rps and Ub genes showed similar expression levels in the transformants and wild-type strains. In contrast, large differences were observed in GK1 and GK2 gene expression. GK1 expression in the GK1_7 clone increased by 4.3-fold in comparison to that observed in the wild type (Figure 3A) and GK2 expression in the GK2_16 clone increased by 3.4-fold (Figure 3B). These results indicate that GK gene expression was enhanced in the GK1_7 and GK2_16 transformants. Moreover, expression of the GK2 gene in the GK1_7 clone and of the GK1 gene in the GK2_16 clone changed negligibly, suggesting that specific overexpression of GK1 and GK2 had been achieved. However, based on the comparison of the cycle threshold (Ct) values, the expression levels of GK (Ct = 22.5) seemed to be lower than those of the two housekeeping genes rps (Ct = 20.6) and Ub (Ct = 21.6). Further enhancement of the GK gene expression would be attained in the future through the optimization of the promoter region.Figure 3


Enhancement of glycerol metabolism in the oleaginous marine diatom Fistulifera solaris JPCC DA0580 to improve triacylglycerol productivity.

Muto M, Tanaka M, Liang Y, Yoshino T, Matsumoto M, Tanaka T - Biotechnol Biofuels (2015)

Relative mRNA abundance in the wild-type and glycerol kinase (GK) gene transformants. Gene expression was evaluated in the GK1_7 (A) and GK2_16 (B) transformants, with housekeeping genes rps and Ub as controls.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4308894&req=5

Fig3: Relative mRNA abundance in the wild-type and glycerol kinase (GK) gene transformants. Gene expression was evaluated in the GK1_7 (A) and GK2_16 (B) transformants, with housekeeping genes rps and Ub as controls.
Mentions: GK expression levels in GK1_7 and GK2_16 clones were examined by quantitative reverse transcription PCR (qRT-PCR), with housekeeping genes ribosomal protein subunit (rps) and ubiquitin (Ub) as controls (Figure 3). The rps and Ub genes showed similar expression levels in the transformants and wild-type strains. In contrast, large differences were observed in GK1 and GK2 gene expression. GK1 expression in the GK1_7 clone increased by 4.3-fold in comparison to that observed in the wild type (Figure 3A) and GK2 expression in the GK2_16 clone increased by 3.4-fold (Figure 3B). These results indicate that GK gene expression was enhanced in the GK1_7 and GK2_16 transformants. Moreover, expression of the GK2 gene in the GK1_7 clone and of the GK1 gene in the GK2_16 clone changed negligibly, suggesting that specific overexpression of GK1 and GK2 had been achieved. However, based on the comparison of the cycle threshold (Ct) values, the expression levels of GK (Ct = 22.5) seemed to be lower than those of the two housekeeping genes rps (Ct = 20.6) and Ub (Ct = 21.6). Further enhancement of the GK gene expression would be attained in the future through the optimization of the promoter region.Figure 3

Bottom Line: Overexpression of the endogenous glycerol kinase (GK) gene in an oleaginous marine diatom, Fistulifera solaris JPCC DA0580, accelerates glycerol metabolism and improves lipid and biomass productivities.We have demonstrated the potential of metabolic engineering in oleaginous microalgae to improve lipid productivity.Metabolic engineering techniques can be used to optimize BDF production.

View Article: PubMed Central - PubMed

Affiliation: Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 Japan ; JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075 Japan.

ABSTRACT

Background: Microalgal oil is a promising alternative feedstock for biodiesel fuel (BDF). Mixotrophic cultivation with glycerol, the primary byproduct of BDF production, may be used to optimize BDF production. This strategy would reduce costs through glycerol recycling and improve lipid productivity and biomass productivity by overcoming the growth retardation caused by decreased light penetration in high-density culture.

Results: Overexpression of the endogenous glycerol kinase (GK) gene in an oleaginous marine diatom, Fistulifera solaris JPCC DA0580, accelerates glycerol metabolism and improves lipid and biomass productivities. Two candidates were selected from a collection of 90 G418-resistant clones, based on growth and confirmation of genome integration. GK gene expression was higher in the selected clones (GK1_7 and GK2_16) than in the wild-type culture. The GK2_16 clone achieved a 12% increase in lipid productivity.

Conclusion: We have demonstrated the potential of metabolic engineering in oleaginous microalgae to improve lipid productivity. Metabolic engineering techniques can be used to optimize BDF production.

No MeSH data available.


Related in: MedlinePlus