Enhancement of extracellular lipid production by oleaginous yeast through preculture and sequencing batch culture strategy with acetic acid

- An acid-tolerant oleaginous yeast was found.
- The yeast began to release extracellular lipids when acetic acid exceeded 20 g/L.
- Pre-culture of seed yeast using acetate increased the extracellular lipids to 37.7%.
- Sequencing batch cultivation increased the extracellular lipids to 50.5%.

Oleaginous yeast Cryptococcus curvatus MUCL 29819, an acid-tolerant lipid producer, was tested to spill lipids extracellularly using different concentrations of acetic acid as carbon source. Extracellular lipids were released when the yeast was cultured with acetic acid exceeding 20 g/L. The highest production of lipid (5.01 g/L) was obtained when the yeast was cultured with 40 g/L acetic acid. When the yeast was cultivated with moderate concentration (20 g/L) of acetic acid, lipid production was further increased by 49.6% through preculture with 40 g/L acetic acid as stimulant. When applying high concentration (40 g/L) of acetic acid as carbon source in sequencing batch cultivation, extracellular lipids accounted up to 50.5% in the last cycle and the extracellular lipids reached 5.43 g/L through the whole process. This study provides an effective strategy to enhance extracellular lipid production and facilitate the recovery of microbial lipids.