Microbial production of hydroxy fatty acids utilizing crude glycerol

Abstract

Strain D2 was isolated from a natural sample as a crude glycerol-assimilating microorganism. The ITS-5.8S rDNA sequence of strain D2 was most similar to that of Fusarium solani deposited in the NCBI database. Strain D2 accumulated 10-hydroxy-cis-12-octadecenoic acid (HYA), 10-hydroxyoctadecanoic acid (HYB), and 10-oxooctadecanoic acid (KetoB) in a medium containing crude glycerol, as a carbon source, and yeast extract, named CG medium. The growth and HYB production of strain D2 depended on the crude glycerol concentration in the medium. Strain D2 produced 2.20 g/L (40% of total fatty acids) of HYB on cultivation in CG medium containing 8% crude glycerol. When strain D2 was cultivated in CG medium containing 6% crude glycerol, the yield of HYB on cultivation under 4 days-shaking and 3 days-static conditions reached 1.19 g/L, which was 2.2 times higher than that under 7 days-shaking conditions and accounted for 53% of total fatty acids. The fungus was found not only to efficiently produce fatty acids utilizing crude glycerol, but also to be the first filamentous fungus to produce hydroxy and oxo fatty acids such as HYB, HYA, and KetoB.