Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química y Biología (CICA), BIOENGIN group, University of La Coruña, E-15008-La, Coruña, Spain.
Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química y Biología (CICA), BIOENGIN group, University of La Coruña, E-15008-La, Coruña, Spain.
Chemosphere. 2024 Oct;365:143345. doi: 10.1016/j.chemosphere.2024.143345. Epub 2024 Sep 13.
There is growing scientific interest in oleaginous yeasts producing microbial oils as precursors of biofuels and potential substitutes for fossil fuels. Due to the high cost of substrates commonly metabolized by yeasts, volatile fatty acids (VFAs) are gaining interest as alternative cheap and sustainable carbon sources, which can be obtained from solid, liquid and gas pollutants. In this research, Rhodosporidium toruloides was proven to be able to accumulate microbial oils from VFAs obtained from the fermentation of syngas by Clostridium carboxidivorans. Using CO and CO as carbon sources from the syngas mixture and H as energy source, this acetogen produced, via the Wood-Ljungdahl pathway, a mixture of acetic, butyric and caproic acids. It was first revealed that R. toruloides exhibited minimal inhibition at concentrations below 12 g/L when exposed to a mixture of VFAs, which included acetic, butyric and even hexanoic acids. The yeast was then grown on the culture medium derived from the acetogenic fermentation of syngas. Between the two yeast strains tested of the same species, R. toruloides DSM 4444 reached a total VFAs consumption of 69.1 g/L, supplied by successive additions of acids to the reactor, yielding a maximum lipid content of 29.7% w/w cell. The lipid profile obtained in this case, in terms of abundance followed the order C18:1 > C16:0 ≥ C18:0 > C18:2>others; in which the dominant compound (C18:1), represented approximately 50% of the total. This research opens new possibilities in the cultivation of oleaginous yeasts for the production of biofuels and bioproducts from C1 gases.
越来越多的科学家对产生微生物油脂的油脂酵母感兴趣，因为这些油脂可以作为生物燃料的前体和潜在的化石燃料替代品。由于酵母通常代谢的基质成本高昂，挥发性脂肪酸（VFAs）作为替代廉价和可持续的碳源引起了人们的兴趣，这些碳源可以从固体、液体和气体污染物中获得。在这项研究中，证明了嗜热脂肪红酵母能够从产乙酸梭菌发酵合成气得到的 VFAs 中积累微生物油脂。该产乙酸梭菌利用混合气中的 CO 和 CO2 作为碳源，H2 作为能源，通过 Wood-Ljungdahl 途径，产生了乙酸、丁酸和己酸的混合物。首次揭示了在浓度低于 12 g/L 时，R. toruloides 对 VFA 混合物的抑制作用最小，该混合物包含乙酸、丁酸甚至己酸。然后，酵母在源自合成气产乙酸发酵的培养基中生长。在测试的两种相同种属的酵母菌株中，R. toruloides DSM 4444 在通过向反应器连续添加酸的情况下，达到了 69.1 g/L 的总 VFA 消耗，最高产脂量达到了 29.7%w/w 细胞。在这种情况下获得的脂质谱，就丰度而言，遵循 C18:1>C16:0≥C18:0>C18:2>其他的顺序；其中优势化合物（C18:1）约占总量的 50%。这项研究为利用油脂酵母从 C1 气体生产生物燃料和生物产品开辟了新的可能性。
