Ochsenreither Katrin, Glück Claudia, Stressler Timo, Fischer Lutz, Syldatk Christoph
Technical Biology, Institute of Process Engineering in Life Sciences, Karlsruhe Institute of Technology Karlsruhe, Germany.
Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim Stuttgart, Germany.
Front Microbiol. 2016 Oct 5;7:1539. doi: 10.3389/fmicb.2016.01539. eCollection 2016.
Polyunsaturated fatty acids (PUFAs) of the ω-3 and ω-6 class (e.g., α-linolenic acid, linoleic acid) are essential for maintaining biofunctions in mammalians like humans. Due to the fact that humans cannot synthesize these essential fatty acids, they must be taken up from different food sources. Classical sources for these fatty acids are porcine liver and fish oil. However, microbial lipids or single cell oils, produced by oleaginous microorganisms such as algae, fungi and bacteria, are a promising source as well. These single cell oils can be used for many valuable chemicals with applications not only for nutrition but also for fuels and are therefore an ideal basis for a bio-based economy. A crucial point for the establishment of microbial lipids utilization is the cost-effective production and purification of fuels or products of higher value. The fermentative production can be realized by submerged (SmF) or solid state fermentation (SSF). The yield and the composition of the obtained microbial lipids depend on the type of fermentation and the particular conditions (e.g., medium, pH-value, temperature, aeration, nitrogen source). From an economical point of view, waste or by-product streams can be used as cheap and renewable carbon and nitrogen sources. In general, downstream processing costs are one of the major obstacles to be solved for full economic efficiency of microbial lipids. For the extraction of lipids from microbial biomass cell disruption is most important, because efficiency of cell disruption directly influences subsequent downstream operations and overall extraction efficiencies. A multitude of cell disruption and lipid extraction methods are available, conventional as well as newly emerging methods, which will be described and discussed in terms of large scale applicability, their potential in a modern biorefinery and their influence on product quality. Furthermore, an overview is given about applications of microbial lipids or derived fatty acids with emphasis on food applications.
ω-3和ω-6类多不饱和脂肪酸(PUFAs)(如α-亚麻酸、亚油酸)对于维持人类等哺乳动物的生物功能至关重要。由于人类无法合成这些必需脂肪酸,因此必须从不同食物来源获取。这些脂肪酸的传统来源是猪肝和鱼油。然而,由藻类、真菌和细菌等产油微生物生产的微生物脂质或单细胞油也是一种很有前景的来源。这些单细胞油可用于许多有价值的化学品,不仅应用于营养领域,还可用于燃料,因此是生物基经济的理想基础。建立微生物脂质利用的一个关键点是具有成本效益地生产和纯化燃料或高价值产品。发酵生产可以通过深层发酵(SmF)或固态发酵(SSF)来实现。所获得的微生物脂质的产量和组成取决于发酵类型和特定条件(如培养基、pH值、温度、通气、氮源)。从经济角度来看,废物流或副产品流可以用作廉价且可再生的碳源和氮源。一般来说,下游加工成本是实现微生物脂质完全经济效率需要解决的主要障碍之一。对于从微生物生物质中提取脂质,细胞破碎最为重要,因为细胞破碎效率直接影响后续的下游操作和整体提取效率。有多种细胞破碎和脂质提取方法可供选择,包括传统方法和新出现的方法,将从大规模适用性、在现代生物炼制中的潜力以及对产品质量的影响等方面进行描述和讨论。此外,还将概述微生物脂质或衍生脂肪酸的应用,重点是食品应用。