Two-stage syngas fermentation into microbial oils and β-carotene with Clostridium carboxidivorans and engineered Yarrowia lipolytica

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG

[Abstract] An engineered Yarrowia lipolytica strain was able to simultaneously accumulate microbial oils and β-carotene from both acetic and butyric acids produced from syngas fermentation by Clostridium carboxidivorans, through the Wood-Ljungdahl pathway, with CO and CO2 as carbon sources. It was first determined that Y. lipolytica showed no inhibition at concentrations < 16 g/L of a mixture of VFAs (Volatile Fatty Acids) containing acetic, butyric, and even hexanoic acids. The yeast was then grown in a bioreactor with a culture medium derived from acetogenic syngas (CO, CO2, H2) fermentation containing all three acids. Y. lipolytica consumed a total of 91 g/L VFAs, progressively supplied through eight successive additions of these acids to the reactor. A maximum lipid content of 36.18% g/g cell was achieved at 61 g/L VFAs consumed and with an airflow rate of 2.0 vvm. Besides, a total of 88.4 mg/g cell and 759 mg/L β-carotene content and concentration were achieved at about 80 g/L VFAs consumed and with a 2.0 vvm airflow rate. It was concluded that; a non-limiting air flow favors the metabolic pathway for β-carotene formation against lipid accumulation

This research is part of projects funded by the Spanish Ministry of Science and Innovation and European FEDER funds (PID2020-117805RB-I00; TED2021-130055B-I00). RR thanks that same Ministry for financially supporting his doctoral contract (E-15-2019-0344365). The manuscript is based on research related to COST action Yeast4Bio. The authors, belonging to the BIOENGIN group, thank Xunta de Galicia for financial support to Competitive Reference Research Groups (ED431C 2021/55). Funding for open access charge was covered by Universidade da Coruña/CISUG.

Xunta de Galicia; ED431C 2021/55