Assessing an effective feeding strategy to optimize crude glycerol utilization as sustainable carbon source for lipid accumulation in oleaginous yeasts

Microbial Cell Factories

Research

Paolo Mereghetti¹  Paola Branduardi²  Lorenzo Signori²  Danilo Porro²  Andrea Giuzzi²  Riccardo Posteri²  Diletta Ami³ 

[1] Center for Nanotechnology Innovation@NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127, Pisa, Italy;Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy;Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy;Department of Physics, University of Milano-Bicocca, Piazza della Scienza 3, 20126, Milan, Italy;Consorzio Nazionale Interuniversitario per le Scienze fisiche della Materia (CNISM), UdR Milano-Bicocca, Via R. Cozzi 53, 20126, Milan, Italy;

关键词: Cryptococcus curvatus;    Rhodosporidium toruloides;    Lipomyces starkeyi;    Crude glycerol;    Fatty acids methyl esters (FAME);    Flow-cytometry;    Fourier transform infrared (FTIR) microspectroscopy;    Principal component analysis (PCA);   

DOI  :  10.1186/s12934-016-0467-x

 received in 2015-12-21, accepted in 2016-04-20,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundMicrobial lipids can represent a valuable alternative feedstock for biodiesel production in the context of a viable bio-based economy. This production can be driven by cultivating some oleaginous microorganisms on crude-glycerol, a 10 % (w/w) by-product produced during the transesterification process from oils into biodiesel. Despite attractive, the perspective is still economically unsustainable, mainly because impurities in crude glycerol can negatively affect microbial performances. In this view, the selection of the best cell factory, together with the development of a robust and effective production process are primary requirements.ResultsThe present work compared crude versus pure glycerol as carbon sources for lipid production by three different oleaginous yeasts: Rhodosporidium toruloides (DSM 4444), Lipomyces starkeyi (DSM 70295) and Cryptococcus curvatus (DSM 70022). An efficient yet simple feeding strategy for avoiding the lag phase caused by growth on crude glycerol was developed, leading to high biomass and lipid production for all the tested yeasts. Flow-cytometry and fourier transform infrared (FTIR) microspectroscopy, supported by principal component analysis (PCA), were used as non-invasive and quick techniques to monitor, compare and analyze the lipid production over time. Gas chromatography (GC) analysis completed the quali-quantitative description. Under these operative conditions, the highest lipid content (up to 60.9 % wt/wt) was measured in R. toruloides, while L. starkeyi showed the fastest glycerol consumption rate (1.05 g L−1 h−1). Being productivity the most industrially relevant feature to be pursued, under the presented optimized conditions R. toruloides showed the best lipid productivity (0.13 and 0.15 g L−1 h−1 on pure and crude glycerol, respectively).ConclusionsHere we demonstrated that the development of an efficient feeding strategy is sufficient in preventing the inhibitory effect of crude glycerol, and robust enough to ensure high lipid accumulation by three different oleaginous yeasts. Single cell and in situ analyses allowed depicting and comparing the transition between growth and lipid accumulation occurring differently for the three different yeasts. These data provide novel information that can be exploited for screening the best cell factory, moving towards a sustainable microbial biodiesel production.

【 授权许可】

CC BY   
© Signori et al. 2016

【 图 表 】

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