Comparison and modification of models in production of biosurfactant for Paenibacillus alvei and Bacillus mycoides and its effect on MEOR efficiency

• Ability of biosurfactant production at wide range of pH and temperature.
• Producing preferable surface-active substance.
• Response surface methodology (RSM) was exploited to optimize biosurfactant production.
• The developed model was found to be adequate to describe the biosurfactant production.
• Modified model has significant role in bacterial efficiency for enhanced oil recovery.

Biosurfactant production from two indigenous consortia has already been investigated in two previous studies. In this study, comparison and modification of those models for having as much biosurfactant as possible was conducted. After characterization of bacteria by biochemical tests and 16S ribotyping, a fully modification on the final models was presented. Response surface methodology has the ability to investigate the liability of the parameters and models by the help of Desirability mode and R2 coefficient in Design Expert software. Our models in the previous works follow the style of (y=f(A,B,…)) and two Desirability of 0.968 and 0.996 for Paenibacillus alvei ARN63 and Bacillus mycoides SH2, respectively. After modification by the help of Cox–Box tools in the software, two new models were in the forms of (y3=f1(A,B,…)) and (y0.57=f2(A,B,…)) and their Desirability were 1 and 0.988, respectively which are much more reliable than the previous ones. These new models present a higher R2 and precision comparing to the non-modified data and models. Analysis of variance for both consortia showed the independency of P. alvei ARN63 from temperature and B. mycoides SH2 from lonely variations of pH and salinity. Finally, the effect of this modification has examined on enhancing oil recovery by produced biosurfactants. The results show that the modified model obtained in this study has significant role in modes of enhancing bacterial efficiency for surfactant enhanced oil recovery.