Effect of Salt Addition upon the Production of Metabolic Compounds by Yarrowia lipolytica Cultivated on Biodiesel-Derived Glycerol Diluted with Olive-Mill Wastewaters
Effect of Salt Addition upon the Production of Metabolic Compounds by Yarrowia lipolytica Cultivated on Biodiesel-Derived Glycerol Diluted with Olive-Mill Wastewaters
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DOI：
10.3390/en12193649
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发表时间：
2019-09
期刊：
影响因子：
3.2
通讯作者：
M. Tzirita;Maria Kremmyda;D. Sarris;A. Koutinas;S. Papanikolaou
中科院分区：
文献类型：
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作者：
M. Tzirita;Maria Kremmyda;D. Sarris;A. Koutinas;S. Papanikolaou
主要的环境问题之一是来自橄榄油生产的剧毒的农业工业废水，称为橄榄磨废水(OMW)。另一方面，生物液体燃料工业(生物柴油和生物乙醇)的持续发展使其主要副产品粗甘油的加工和开发成为强制性的。本研究利用非常规酵母菌Yarrowia lisoltica，在用OMWs稀释的培养基中，对生物柴油粗甘油进行了生物技术转化。OMWs同时作为液体介质和底物是近年来工业生物技术领域出现的一个新趋势，利用OMWs可以同时对废渣进行部分脱毒(即脱色和脱酚)来生产增值代谢物。在本研究中，以稀释后的有机废渣(总酚含量为2.0g/L)与70.0g/L粗甘油混合作为底物。研究了解脂耶尔森菌ACA-YC5031菌株在有利于产生次生代谢物(柠檬酸、多元醇、微生物脂类、多糖)的有限氮源中产生增值化合物的条件。通过摇瓶分批培养，研究了添加不同浓度的氯化钠(1.0%、3.0%、5.0%w/w)对菌株生化行为的影响。在所有试验中都观察到了显著的生物量产生，而在空白试验中(不加OMWs和不加盐)，代谢转向合成多元醇(Σ多元醇=甘露醇+阿拉伯醇+赤藓糖醇>；20g/L，最大总柠檬酸-Cit(柠檬酸和异柠檬酸之和)=10.5g/L)。在添加5.0%Σ的条件下，添加OMWs后Citmax为32.7g/L，Cit多元醇浓度降至-lt；15g/L，而Cit产量急剧增加，最终达到54.0g/L(单位甘油转化率=0.82g/g)。最后，观察到了显著的颜色和酚的去除，评估了酵母作为OW的去污介质和生产附加值化合物的很好的候选者。
One of the major environmental problems is the highly toxic agro-industrial waste called olive mill wastewater (OMW), deriving from olive oil production. On the other hand, the continuous development of the biological liquid fuel industry (biodiesel and bioethanol) makes it mandatory the process and exploitation of their main by-products, crude glycerol. This study dealt with the biotechnological conversions of biodiesel-derived crude glycerol with the use of the non-conventional yeast Yarrowia lipolytica in media that had been diluted with OMWs. OMWs, employed as simultaneous liquid medium and substrate, is a new trend recently appearing in Industrial Biotechnology, where value-added metabolites could be produced with simultaneous partial detoxification (i.e. decolorization and phenol removal) of the used residue. In the present study, diluted OMWs (containing 2.0 g/L of total phenolic compounds) blended with 70.0 g/L crude glycerol were employed as substrates. Production of value-added compounds by Y. lipolytica strain ACA-YC 5031 was studied in nitrogen-limited media favoring the production of secondary metabolites (i.e. citric acid, polyols, microbial lipids, polysaccharides). Batch-flask cultures were carried out and the impact of the addition of different NaCl concentrations (1.0%, 3.0%, 5.0% w/w) added upon the biochemical behavior of the strain was studied. Remarkable biomass production was observed in all trials, while in the “blank” experiment (no OMWs and no salt added), the metabolism was shifted toward the synthesis of polyols (Σpolyols = mannitol + arabitol + erythritol > 20 g/L and maximum total citric acid-Cit (sum of citric and isocitric acid) = 10.5 g/L). Addition of OMWs resulted in Citmax = 32.7 g/L, while Σpolyols concentration dropped to <15 g/L. Addition of salt in the OMW-based media slightly reduced the produced biomass, while Cit production drastically increased, reaching a final value of 54.0 g/L (conversion yield of Cit produced per unit of glycerol consumed = 0.82 g/g) in the trial with addition of 5.0% NaCl. Finally, significant color and phenols removal were observed, evaluating the yeast as a decontamination medium for the OMW and a great candidate for the production of value-added compounds.