Surfactin Production by B. Subtilis Using Oil Lee Mix as Substrate

Biosurfactants have similar characteristics to surfactants, being synthesized by microorganisms and have a great ability to reduce the surface tension of liquids, having low toxicity and high biodegradability. The objective of this work was to evaluate the production of the biosurfactant surfactin produced from Bacillus subtilis having as substrate the residual oily sludge from the manufacture of soybean and cottonseed oils. The use of this oily sludge mixture has not yet been reported in research for this purpose. For this, an experimental design was carried out, using the factorial design of the central compound using different concentrations of glucose and oily sludge as a substrate in the fermentation by Bacillus subtilis, keeping other variables, such as: temperature, agitation and pH at constant values. After the surfactin fermentation and purification process, analyzes were performed to determine the surfactin by high-performance liquid chromatography (HPLC), as well as the biomass and substrate conversion factors into surfactin. It is noteworthy that in the substrate containing 3% (m/v) of glucose and 6% (m/v) of oily sludge, there was a higher production of surfactin (126.80 mg.L-1), in the fermented broth, on average. The results obtained can demonstrate that the oily sludge can be a suitable substrate for the production of surfactin by Bacillus subtilis.

Automated summary

This study evaluated the production of the biosurfactant surfactin using residual oily sludge as a substrate and found that the highest surfactin production was achieved with a substrate containing 3% glucose and 6% oily sludge.