Comparison of Nitrogen Depletion and Repletion on Lipid Production in Yeast and Fungal Species
1
National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
2
Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
*
Authors to whom correspondence should be addressed.
Academic Editor: Thomas E. Amidon
Energies 2016, 9(9), 685; https://doi.org/10.3390/en9090685
Received: 18 June 2016
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Revised: 18 August 2016
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Accepted: 24 August 2016
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Published: 29 August 2016
(This article belongs to the Collection Bioenergy and Biofuel)
Although it is well known that low nitrogen stimulates lipid accumulation, especially for algae and some oleaginous yeast, few studies have been conducted in fungal species, especially on the impact of different nitrogen deficiency strategies. In this study, we use two promising consolidated bioprocessing (CBP) candidates to examine the impact of two nitrogen deficiency strategies on lipid production, which are the extensively investigated oleaginous yeast Yarrowia lipolytica, and the commercial cellulase producer Trichoderma reesei. We first utilized bioinformatics approaches to reconstruct the fatty acid metabolic pathway and demonstrated the presence of a triacylglycerol (TAG) biosynthesis pathway in Trichoderma reesei. We then examined the lipid production of Trichoderma reesei and Y. lipomyces in different media using two nitrogen deficiency strategies of nitrogen natural repletion and nitrogen depletion through centrifugation. Our results demonstrated that nitrogen depletion was better than nitrogen repletion with about 30% lipid increase for Trichoderma reesei and Y. lipomyces, and could be an option to improve lipid production in both oleaginous yeast and filamentous fungal species. The resulting distinctive lipid composition profiles indicated that the impacts of nitrogen depletion on yeast were different from those for fungal species. Under three types of C/N ratio conditions, C16 and C18 fatty acids were the predominant forms of lipids for both Trichoderma reesei and Y. lipolytica. While the overall fatty acid methyl ester (FAME) profiles of Trichoderma reesei were similar, the overall FAME profiles of Y. lipolytica observed a shift. The fatty acid metabolic pathway reconstructed in this work supports previous reports of lipid production in T. reesei, and provides a pathway for future omics studies and metabolic engineering efforts. Further investigation to identify the genetic targets responsible for the effect of nitrogen depletion on lipid production improvement will facilitate strain engineering to boost lipid production under more optimal conditions for productivity than those required for nitrogen depletion.
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Keywords:
advanced biofuel; lipids; nitrogen depletion; nitrogen repletion; Trichoderma reesei; Yarrowia lipolytica
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MDPI and ACS Style
Yang, S.; Wang, W.; Wei, H.; Van Wychen, S.; Pienkos, P.T.; Zhang, M.; Himmel, M.E. Comparison of Nitrogen Depletion and Repletion on Lipid Production in Yeast and Fungal Species. Energies 2016, 9, 685. https://doi.org/10.3390/en9090685
AMA Style
Yang S, Wang W, Wei H, Van Wychen S, Pienkos PT, Zhang M, Himmel ME. Comparison of Nitrogen Depletion and Repletion on Lipid Production in Yeast and Fungal Species. Energies. 2016; 9(9):685. https://doi.org/10.3390/en9090685
Chicago/Turabian StyleYang, Shihui, Wei Wang, Hui Wei, Stefanie Van Wychen, Philip T. Pienkos, Min Zhang, and Michael E. Himmel. 2016. "Comparison of Nitrogen Depletion and Repletion on Lipid Production in Yeast and Fungal Species" Energies 9, no. 9: 685. https://doi.org/10.3390/en9090685
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