Biosurfactant production and growth kinetics of bacteria in a designer marine medium: improved physiochemical properties

A combinatorial screening strategy was adopted for the development of a suitable medium for enhanced biosurfactant production by a marine strain. As a result, a modified marine medium (MMM) was developed, which contained urea and strontium chloride besides other salts important for the growth of marine bacteria. This medium supported growth, evident from a higher maximum growth rate value of 0.42 h(-1) and an enhanced biosurfactant production of 2.58 g/L. The critical micelle concentration (CMC) was determined for the biosurfactants obtained from all tested media combinations. The biosurfactant produced with this medium was stable at high temperature (100 °C), a wide range of pH (5-11) and salt concentration of 5-35%. The emulsifying activity and stability of the biosurfactant obtained using MMM was better than the biosurfactant obtained using conventional media. This biosurfactant with improved physiochemical properties is suitable for a wide range of applications in industry and for marine environmental cleaning.