Format

Send to

Choose Destination
Appl Microbiol Biotechnol. 2019 Aug;103(15):6297-6308. doi: 10.1007/s00253-019-09936-3. Epub 2019 Jun 5.

Highly selective isolation and characterization of Lipomyces starkeyi mutants with increased production of triacylglycerol.

Author information

1
Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata, 956-8603, Japan.
2
Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, 940-2188, Japan.
3
Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan.
4
Research Institute for Creating the Future, FUJI OIL HOLDINGS INC, 4-3 Kinunodai, Tsukubamirai-shi, Ibaraki, 300-2497, Japan.
5
Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata, 956-8603, Japan. htakaku@nupals.ac.jp.

Abstract

The oleaginous yeast Lipomyces starkeyi is an attractive organism for the industrial production of lipids; however, the amount of lipid produced by wild-type L. starkeyi is insufficient. The study aims to obtain L. starkeyi mutants that rapidly accumulate large amounts of triacylglycerol (TAG). Mutagenized yeast cells at the early stages of cultivation were subjected to Percoll density gradient centrifugation; cells with increased production of TAG were expected to be enriched in the resultant upper fraction because of their lower density. Among 120 candidates from the upper fractions, five mutants were isolated that accumulated higher amounts of TAG. Moreover, when omitting cells with mucoid colony morphology, 11 objective mutants from 11 candidates from the upper fraction were effectively (100%) isolated. Of total 16 mutants obtained, detailed characterization of five mutants was performed to reveal that five mutants achieved about 1.5-2.0 times TAG concentration (4.7-6.0 g/L) as compared with the wild-type strain (3.6 g/L) at day 5. Among these five mutants, strain E15 was the best for industrial use because only strain E15 showed significantly higher TAG concentration as well as significantly higher degree of lipid to glucose and biomass to glucose yields than the wild-type strain. Thus, Percoll density gradient centrifugation is an effective method to isolate mutant cells that rapidly accumulate large amounts of TAG. It is expected that by repeating this procedure as part of a yeast-breeding program, L. starkeyi mutants suitable for industrial lipid production can be easily and effectively obtained.

KEYWORDS:

Lipid droplet; Lipomyces starkeyi; Oleaginous yeast; Percoll; Triacylglycerol

PMID:
31165226
DOI:
10.1007/s00253-019-09936-3

Supplemental Content

Full text links

Icon for Springer
Loading ...
Support Center