Study on the production of Sophorolipid by Starmerella bombicola yeast using waste fried oil fermentation

Abstract

Sophorolipid (SLs) are surface active compounds that have excellent surface-lowering properties. SLs was produced by Starmerella bombicola (CGMCC1576) yeast with sunflower seeds oil, fried waste oil, cooked tung oil and raw tung oil used as hydrophobic carbon sources. The results showed that the strain could use sunflower seed oil and fried waste oil as hydrophobic carbon sources to produce SLs, and the yields were 44.52 and 39.09 gL-1, and it could not use cooked tung oil and raw tung oil. Analysis by high performance liquid chromatography-high resolution mass spectrometry (HPLC-MS/MS) showed that the main composition and structure of SLs produced by fermentation using waste fried waste oil were similar to that of sunflower seed oil as hydrophobic carbon source. The yield of SLs was the highest when the fried waste oil was used as hydrophobic carbon source, glucose 8%, waste oil 6% and yeast 0.3%. When fried waste oil was used as hydrophobic carbon source in a parallel 4-strand fermentation tank (FT), the combination with the largest yield and the most cost saving was that 3% of fried waste oil was added into the initial medium, and another 3% was again added after 72h of fermentation. The total yield of SLs was 121.28 gL-1, and the yield of lactone SLs was 48.07 gL-1.