Biosurfactant production by native marine bacteria (Acinetobacter calcoaceticus P1-1A) using waste carbon sources: Impact of process conditions

The high cost of biosurfactant production is an obstacle for widespread commercial applications. Cost-effective generation of biosurfactants could be achieved using industrial wastes and by-products as substrates and tailoring cultural conditions. In this work, waste streams including refined waste cooking oil and crude glycerol were compared to each other and to commercial carbon sources. Based on this assessment, the waste cooking oil was selected for further studies. A response surface methodology (RSM) was then used to study biosurfactant production by Acinetobacter calcoaceticus P1-1A strain (a strain indigenous to the North Atlantic Ocean) using the refined waste cooking oil as the sole carbon source. The concentrations of carbon, nitrogen, and NaCl, as well as the initial pH and temperature were varied. The emulsification index was measured as the response. The cultural conditions to reach the maximum emulsification index (68.17%) were 0.0435 v/v (4.35 vol.%) refined waste cooking oil, 6.5 g/L ammonium sulphate, 13.5 g/L NaCl, initial pH of 7.7, and temperature of 34.8 degrees C. The experimental validation of the predicted response under optimum conditions was performed with 862 mg/L of the biosurfactant product generated. The product showed high thermal, pH, and salinity stability. The use of this indigenous bacteria combined with the use of a no-cost carbon source from waste has the potential to not only reduce costs associated with biosurfactant production but also to produce a biosurfactant better suited to treat oil spills in the harsh environment of the North Atlantic and other cold waters.

Automated summary

This study demonstrates the cost-effective production of biosurfactants using waste substrates and optimized cultural conditions. By using waste cooking oil as the sole carbon source, a biosurfactant with high stability in thermal, pH, and salinity conditions was successfully produced. The combination of indigenous bacteria and no-cost carbon sources from waste shows great promise in reducing production costs and producing biosurfactants tailored for harsh environments like the North Atlantic.