Development of yeast Saccharomyces cerevisae engineered for high lipid content
Oils are important as edible use and industrial feedstock chemicals. Increasing global demand for oils and their potential roles as an alternative of diminishing fossil-derived resources prompt us to exploit new oil sources, which can be designed to satisfy various requirements. We have been engineering the budding yeast Saccharomyces cerevisiae to be suitable for oil production. Although S. cerevisiae is one of the most readily engineered organisms, its lipid content is as low as 5-7%. In this paper, we succeeded in increasing the lipid content up to 45% by overexpressing the N-terminally truncated Dga1p (diacylglycerol acyltransferase ) in the dga1 disruptant. We found that the dga1 disruption modulated the expression of ESA1, a neighbor gene encoding histone acetyltransferase, which may be involved in the increased lipid accumulation. This lipid content is so high as natural oleaginous yeast that this yeast strain may be useful as a host engineered for oil production.
- Kamisaka, Y., Kimura, K., Uemura, H., Yamaoka, M. (2013) Overexpression of the active diacylglycerol acyltransferase variant transforms Saccharomyces cerevisiae into an oleaginous yeast. Appl. Microbiol. Biotechnol. 97, 7345-7355
Palmitoleic acid production by oleaginously engineered Saccharomyces cerevisae
Palmitoleic acid (16:1, n-7, POA) has recently gained attention for its health benefits and as a potential resource for industrial feedstock. POA is relatively rare in common plant oils, and attempts have been made to develop new sources of POA. Saccharomyces cerevisiae has a high content of POA, although its low lipid content per dry cell weight makes the yeast unsuitable for the source of POA production. Since we previously prepared engineered yeast with lipid content up to 45% by overexpressing N-terminally truncated Dga1p (diacylglycerol acyltransferase ) in the dga1 disruptant, we attempted to develop POA production system based on the engineered yeast. In this paper, we succeeded in increasing POA production by addition of 2g/l methionine in the medium under low cultivation temperatures (20-25C). The optimization of culture conditions induced 2.5-fold increase in POA production, which corresponded to 0.97g POA/l . The results indicate that the engineered yeast is a potential source of POA.
- Kamisaka, Y., Kimura, K., Uemura, H., Yamaoka, M. Addition of methionine and low cultivation temperatures increase palmitoleic acid production by engineered Saccharomyces cerevisiae, Appl. Microbiol. Biotechnol. 99, 201-210 (2015)
ecretory production of ricinoleic acid by the engineered fission yeastSchizosaccharomyces pombe
In fear of the depletion of oil resources and the global warming, the bio-resources for the production of fuels and chemical materials become more important these days. One of the highlights is polyurethane, which is made of ricinoleic acid from castor oil. As castor beans contain ricin, a toxic protein, however, it is expected to look for other resources of ricinoleic acid. Thus, we chose S. pombe as a host cell, because of its high composition (80%) of oleic acid, and the heterologous fatty acid hydroxylase (FAH12) that introduces OH group into oleic acid was expressed in S. pombe. The strain of high ricinoleic acid content (above 50% of fatty acid composition) was successfully established. Furthermore, utilization of the phospholipase Plg7p suppressed ricinoleic acid toxicity in S. pombe, and facilitated secretion of a significantly high amount of free ricinoleic acid into culture media. These findings opened up possibilities of secretory production of ricinoleic acid in S. pombe.
- R. Holic, H. Yazawa, H. Kumagai, H. Uemura*, Engineered high content of ricinoleic acid in fission yeast Schizosaccharomyces pombe. Appl. Microbiol. Biotech. 95: 179-187 (2012). DOI: 10.1007/s00253-012-3959-6
- H. Yazawa, H. Kumagai, H. Uemura*, Characterization of triglyceride lipase genes of fission yeast Schizosaccharomyces pombe. Appl. Microbiol. Biotech. 96: 981-991 (2012). DOI: 10.1007/s00253-012-4151-8
- H. Yazawa, R. Holic, H. Kumagai, H. Uemura*, Toxicity of ricinoleic acid production in fission yeast Schizosaccharomyces pombe is suppressed by the overexpression of plg7, a phospholipase A2 of a platelet-activating factor (PAF) family homolog. Appl. Microbiol. Biotech. 97: 8193-8203 (2013). DOI: 10.1007/s00253-013-4987-6
- H. Yazawa, H. Kumagai, H. Uemura*, Secretory production of ricinoleic acid in fission yeast Schizosaccharomyces pombe. Appl. Microbiol. Biotech. 97: 8663-8671 (2013). DOI: 10.1007/s00253-013-5060-1
