Different metal ions were added as supplements to culture media to study sophorolipids production by Wickerhamiella domercqiae Y2A CGMCC 3798. The fermentation media were supplemented with different metal ions in the form of sulfate. A maximum yield 149.90 g/L was achieved in the presence of Cu2+ ions. The production of lactonic sophorolipids was favored when culture media wad supplied with Mg2+ ions, while Fe2+ ions were the optimal ions for acidic sophorolipids production. TLC, HPLC, and LC–MS analyses were used for further investigation on the sophorolipids production. The results of SDS–PAGE and enzymatic transformation of acidic sophorolipids showed differential expression of extracellular proteins of W. domercqiae Y2A CGMCC 3798 in presence of Mg2+ or Fe2+. Overall the results indicated potential selective production of different sophorolipids based on selected metal ions in culture media.
Practical applications: During the fermentation process of sophorolipids, L-SLs and A-SLs were produced selectively by adding Mg2+ and Fe2+into fermentation media, respectively.
Sophorolipid composition and production are different produced by Wickerhamiella domercqiae Y2A CGMCC 3798 cultured with Mg2+ (a) and Fe2+ (b), respectively by HPLC analysis.