Assessing an effective feeding strategy to optimize crude glycerol utilization as sustainable carbon source for lipid accumulation in oleaginous yeasts.
Assessing an effective feeding strategy to optimize crude glycerol utilization as sustainable carbon source for lipid accumulation in oleaginous yeasts.
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DOI：
10.1186/s12934-016-0467-x
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发表时间：
2016-05-05
影响因子：
6.4
通讯作者：
Branduardi P
中科院分区：
文献类型：
--
作者：
Signori L;Ami D;Posteri R;Giuzzi A;Mereghetti P;Porro D;Branduardi P
在可行的生物经济背景下，微生物脂类可作为生物柴油生产的有价值的替代原料。这种生产可以通过在粗甘油上培养一些含油微生物来推动，甘油是从油脂到生物柴油的酯交换过程中产生的一种10%(w/w)的副产品。尽管很有吸引力，但这一前景在经济上仍然是不可持续的，主要是因为粗甘油中的杂质会对微生物的性能产生负面影响。在这种观点下，选择最好的电池工厂，以及开发稳健和有效的生产工艺是主要要求。本工作比较了三种不同含油酵母菌：托鲁氏红孢子菌(DSM 4444)、斯塔基脂肪霉菌(DSM 70295)和隐球菌属(DSM 70022)以甘油为碳源产脂的能力。开发了一种有效而简单的补料策略，以避免因在粗甘油上生长而导致的滞后期，从而导致所有受试酵母的生物量和脂肪产量都很高。在主成分分析(PCA)的支持下，采用流式细胞术和傅里叶变换红外(FTIR)显微光谱分析技术，作为无创、快速的技术，监测、比较和分析随时间推移的脂肪生成。气相色谱(GC)分析完成了定性定量描述。在这些操作条件下，测得的脂肪含量最高(高达60.9%wt/wt)，而斯塔凯氏乳杆菌的甘油消耗速度最快(1.05g/L−1h−1)。作为最具工业相关性的指标，在所提出的优化条件下，罗汉果表现出最好的脂肪产量(分别为L−1和粗甘油−1的0.13和0.15)。在这里，我们证明了开发一种有效的喂养策略足以防止粗甘油的抑制作用，并且足够强大，以确保三种不同的含油酵母的高脂肪积累。单细胞和原位分析可以描述和比较三种不同酵母不同发生的生长和脂肪积累之间的转变。这些数据提供了新的信息，可用于筛选最佳的细胞工厂，朝着可持续的微生物生物柴油生产迈进。本文的在线版本(doi：10.1186/s12934-0160467-x)包含补充材料，授权用户可以使用。
Microbial 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. The 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). Here 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. The online version of this article (doi:10.1186/s12934-016-0467-x) contains supplementary material, which is available to authorized users.