Enhancing the effect of soybean oil refinery byproducts on erythromycin production by Saccharopolyspora erythraea

Erythromycin production is clearly enhanced by the addition of vegetable oils. However, whether this positive effect is brought about by the triglyceride or non-triglyceride fraction, is not clear. The non-triglyceride portions of the oils accumulate in the waste during the refining process leaving mainly triglycerides in the refined oil. In this research, sub-fractions of soybean oil, including lecithin, soap stock, free fatty acid, deodorizer distillate and unsaponifiable matter were supplemented by batch and fed-batch to chemically defined and complex fermentation media. The fermentation flasks were incubated at 30°C for 8 days at 220 rpm. It resulted in the production of low concentrations of oil by-products (1-5 g/l) at the beginning of fermentation, increased antibiotic production and had a greater enhancing effect than using crude oil. However, some fractions of oil such as free fatty acids considerably reduced antibiotic production. The results of this study highlight the advantages of substitution of vegetable oil with its refining by-products in the fermentation media.