Semi-continuous pilot-scale microbial oil production withMetschnikowia pulcherrimaon starch hydrolysate
Semi-continuous pilot-scale microbial oil production withMetschnikowia pulcherrimaon starch hydrolysate
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DOI：
10.1186/s13068-020-01756-2
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发表时间：
2020-07-16
影响因子：
6.3
通讯作者：
Chuck, Christopher J.
中科院分区：
文献类型：
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作者：
Abeln, Felix;Hicks, Robert H.;Chuck, Christopher J.
背景异养微生物油是植物油或化石油在食品和燃料应用中潜在的更可持续的替代品。然而，由于几乎所有的工作在该领域是在实验室规模进行，这样的研究进行有限的工业相关性，并没有给出一个明确的指示，什么是需要产生一个实际的工业process.Metschnikowia pulcherrimais一个非致病性的工业上有前途的产油酵母，具有成本效益的脂质生产，包括广泛的底物摄取，抗菌活性和发酵抑制剂的耐受性的许多优点。在本研究中，M. Pulcherrima在高达350 L的搅拌罐反应器中发酵，工作体积为250 L，分批和半连续操作，以突出潜在的工业相关性。由于是食品级，适合大规模处理，并证明M的低聚糖摄取能力。为了生产一品红，选择葡萄糖浆形式的酶水解淀粉作为发酵原料。结果在2L规模的分批发酵中，脂质浓度达到14.6g L-1，生产能力为0.11g L-1h-1，在50 L规模的分批发酵中，脂质浓度达到15.8g L-1，生产能力为0.10g L-1h-1。最大产脂速率为0.33 g L-1 h（-1）（日平均），但底物摄取速率随寡糖链长度的增加而降低。为了生产1 kg含有高达43%（w/w）脂质的干酵母生物质，需要5.2 kg葡萄糖浆，其中脂质产量高达0.21 g g（-1）消耗的干酵母。在半连续操作中，第一次以相对稳定的脂质生产速率（约0.08 g L-1 h（-1））和脂肪酸谱（约27.6%w/w的脂肪酸饱和度）并且无污染地培养了产油酵母超过2个月。在250-L规模上，观察到类似的结果，最终产生近10 kg脂质，脂质生产率为0.10 g L-1 h（-1）。结论M. Pulcherrima用于工业生物技术及其商业生产食品级油的适用性。需要进一步提高生产率以制造M。pulcherrimalipid生产的工业现实，特别是当涉及较长链的脂肪酸。
Background Heterotrophic microbial oils are potentially a more sustainable alternative to vegetable or fossil oils for food and fuel applications. However, as almost all work in the area is conducted on the laboratory scale, such studies carry limited industrial relevance and do not give a clear indication of what is required to produce an actual industrial process.Metschnikowia pulcherrimais a non-pathogenic industrially promising oleaginous yeast which exhibits numerous advantages for cost-effective lipid production, including a wide substrate uptake, antimicrobial activity and fermentation inhibitor tolerance. In this study,M. pulcherrimawas fermented in stirred tank reactors of up to 350 L with 250-L working volume in both batch and semi-continuous operation to highlight the potential industrial relevance. Due to being food-grade, suitable for handling at scale and to demonstrate the oligosaccharide uptake capacity ofM. pulcherrima, enzyme-hydrolysed starch in the form of glucose syrup was selected as fermentation feedstock. Results In batch fermentations on the 2-L scale, a lipid concentration of 14.6 g L(-1)and productivity of 0.11 g L-1 h(-1)were achieved, which was confirmed at 50 L (15.8 g L-1; 0.10 g L-1 h(-1)). The maximum lipid production rate was 0.33 g L-1 h(-1)(daily average), but the substrate uptake rate decreased with oligosaccharide chain length. To produce 1 kg of dry yeast biomass containing up to 43% (w/w) lipids, 5.2 kg of the glucose syrup was required, with a lipid yield of up to 0.21 g g(-1)consumed saccharides. In semi-continuous operation, for the first time, an oleaginous yeast was cultured for over 2 months with a relatively stable lipid production rate (around 0.08 g L-1 h(-1)) and fatty acid profile (degree of fatty acid saturation around 27.6% w/w), and without contamination. On the 250-L scale, comparable results were observed, culminating in the generation of nearly 10 kg lipids with a lipid productivity of 0.10 g L-1 h(-1). Conclusions The results establish the importance ofM. pulcherrimafor industrial biotechnology and its suitability to commercially produce a food-grade oil. Further improvements in the productivity are required to makeM. pulcherrimalipid production industrial reality, particularly when longer-chain saccharides are involved.