Presentation Information
[4Ferm-02]Lipid production by Lipomyces yeasts and its taxonomic implication
○Atsushi Yamazaki1, Hiroko Kawasaki1, Kenichiro Suzuki1 (1. Biological Resource Center, NITE (NBRC), National Institute of Technology and Evaluation (NITE) (Japan))
Keywords:
Lipomyces,Lipid,Oil-productivity
The yeast strains of the genus Lipomyces are known for the ability of oil (large lipid droplet consisting of triacylglycerol) -accumulation in the cells and are expected to be used for oil production as an alternative to palm oil because of its advantage in industrialization and the similar fatty acid composition to that of palm oil. Only the limited number of strains belonging to Lipomyces starkeyi have been studied for the oil production. In order to obtain strains with high productivity, we have isolated Lipomyces strains from various forest soil samples in Japan. The taxonomic study of more than one thousand isolates revealed the taxonomic diversity of the genus Lipomyces and 15 new species were described in addition to the known species (1-3). We also found the geographic correlation between the species distribution and the latitude of isolation (4). Using our isolates and the reference strains of NBRC culture collection, we conducted the study on their oil-productivity.
[Methods]We investigated the quantitative analysis of the cellular fatty acids of 80 strains of the genus Lipomyces. Yeast cells cultured for 10 days at 28°C on 5G5M medium (5% glucose, 5% malt extract) or YM medium were subjected to bead disruption along with the culture broth, followed by lipid extraction using the method of Bligh & Dyer (5). Cellular fatty acid methyl esters (FAME) samples were prepared by transmethylation reaction described by Ichihara & Fukubayashi (6). Gas chromatography analysis was performed using the internal standard method to measure the amount of fatty acid per culture medium.
[Results and Discussion]Cells grown in YM medium did not contain a large amount of lipids for all the strains studied. Large amounts of lipids were found only in the cells grown in 5G5M medium. The species belonging to Lipomyces sensu stricto, namely L. yamadae, L. spencermatinsiae, L. okinawensis, L. kononenkoae, and L. yarrowii tended to produce higher amounts of lipids. In contrast, species other than Lipomyces sensu stricto, L. japonicus and L. yamanashiensis, exhibited low productivity. These findings suggest that the strains with high oil production are limited in the species of Lipomyces sensu stricto and correlated to the phylogenetic relationship within the genus Lipomyces.
Isolates identified as L. doorenjongii and L. starkeyi isolated from southern region of Japan generally exhibited higher lipid production. It is interesting that oil productivity also showed the geographic relationships in addition to the species distribution.
Among the isolated strains, 5 strains were found to produce more oil than the known benchmark strain, L. starkeyi NBRC 10381. These strains are available from NBRC culture collection and expected to serve as candidates for industrial oil production.
Reference:
1) Yamazaki, A., & Kawasaki, H. (2014). Int J Syst Evol Microbiol 64(8):2566–2572.
2) Yamazaki, A., et al. (2017b). Int J Syst Evol Microbiol 67, 2941–2946.
3) Yamazaki, A., et al. (2020). Int J Syst Evol Microbiol 70, 1372–1397.
4) Yamazaki, A., et al. (2022). Mycoscience, 64(1), 1-10.
5) Bligh, E. G., & Dyer, W. J. (1959). Canadian J Biochem Physiol 37(8), 911-917.
6) Ichihara, K. I., & Fukubayashi, Y. (2010). J Lipid Res 51(3), 635-640.
[Methods]We investigated the quantitative analysis of the cellular fatty acids of 80 strains of the genus Lipomyces. Yeast cells cultured for 10 days at 28°C on 5G5M medium (5% glucose, 5% malt extract) or YM medium were subjected to bead disruption along with the culture broth, followed by lipid extraction using the method of Bligh & Dyer (5). Cellular fatty acid methyl esters (FAME) samples were prepared by transmethylation reaction described by Ichihara & Fukubayashi (6). Gas chromatography analysis was performed using the internal standard method to measure the amount of fatty acid per culture medium.
[Results and Discussion]Cells grown in YM medium did not contain a large amount of lipids for all the strains studied. Large amounts of lipids were found only in the cells grown in 5G5M medium. The species belonging to Lipomyces sensu stricto, namely L. yamadae, L. spencermatinsiae, L. okinawensis, L. kononenkoae, and L. yarrowii tended to produce higher amounts of lipids. In contrast, species other than Lipomyces sensu stricto, L. japonicus and L. yamanashiensis, exhibited low productivity. These findings suggest that the strains with high oil production are limited in the species of Lipomyces sensu stricto and correlated to the phylogenetic relationship within the genus Lipomyces.
Isolates identified as L. doorenjongii and L. starkeyi isolated from southern region of Japan generally exhibited higher lipid production. It is interesting that oil productivity also showed the geographic relationships in addition to the species distribution.
Among the isolated strains, 5 strains were found to produce more oil than the known benchmark strain, L. starkeyi NBRC 10381. These strains are available from NBRC culture collection and expected to serve as candidates for industrial oil production.
Reference:
1) Yamazaki, A., & Kawasaki, H. (2014). Int J Syst Evol Microbiol 64(8):2566–2572.
2) Yamazaki, A., et al. (2017b). Int J Syst Evol Microbiol 67, 2941–2946.
3) Yamazaki, A., et al. (2020). Int J Syst Evol Microbiol 70, 1372–1397.
4) Yamazaki, A., et al. (2022). Mycoscience, 64(1), 1-10.
5) Bligh, E. G., & Dyer, W. J. (1959). Canadian J Biochem Physiol 37(8), 911-917.
6) Ichihara, K. I., & Fukubayashi, Y. (2010). J Lipid Res 51(3), 635-640.
Comment
To browse or post comments, you must log in.Log in