Selection of the Optimal Medium Composition and Cultivation Conditions for the Maximum Yield of Rhamnolipids from Heterologous Producers

Rhamnolipids are highly effective microbial surfactants that can be used as a component of cosmetics and detergents. Heterologous expression of rhamnolipid genes is a way to avoid complex regulation of rhamnolipid biosynthesis. The composition of the medium and cultivation conditions for rhamnolipid producers were optimized. For heterologous Pseudomonas viridiflava AlC1223: P5, P6, P8, when using soybean and tall oil as a carbon source, the maximum yield of the product was obtained, which amounted to: 120.3 ± 0.6, 210.1 ± 1.7, 172 ± 0.3 mg/mL, respectively; in heterologous Escherichia coli BLWT: E14, the highest product yield (43.2 ± 0.4 mg/mL) was observed with glycerol. In all cases, peptone as a nitrogen source had a positive effect on the yield of rhamnolipids. The best source of trace elements is yeast extract for E14 and a mixture of salts (magnesium sulfate and potassium monohydrophosphate) for P5, P6, P8. The increase in temperature and pH has a positive effect on productivity when hydrophobic substrates are used.