Microbial lipids and added value metabolites production by Yarrowia lipolytica from pork lard

Yarrowia lipolytica is a suitable microbial platform to convert low-value hydrophobic substrates into microbial oils and other important metabolites. In this work, this yeast species was used to simultaneously synthetize ex novo lipids and produce citric acid and lipase from animal fat (pork lard) adding higher value to the low-cost fatty substrate. The effect of pH, lard concentration, arabic gum concentration and oxygen mass transfer rate (OTR) on lipids accumulation on Y. lipolytica batch cultures was assessed by an experimental design based on Taguchi method. OTR was by far the most influential parameter in the range of 96 mg L-1 h(-1)-480 mg L-1 h(-1). A bio-modification of initial lipidic substrate was observed and, depending on the nutritional and operational conditions, specialty lipids with specific composition and high added-value were obtained. The unsaturated-tosaturated fatty acids ratio of these microbial lipids is higher than in initial substrate, which indicates that they are more suitable than animal fat for food additives. Moreover, the simultaneous induction of lipase and citric acid by Y. lipolytica growing in animal fat demonstrates that a biorefinery approach may be designed based on animal fat raw material.