Optimization of Process Variables on Yield of Biosurfactant Derived from a Mutant Acinetobacter Sp.

Abstract

Microbial Enhanced Oil Recovery (MEOR) utilizes microorganisms to improve oil extraction from hydrocarbon reservoirs, with its success hinging on selecting potent strains that can produce high-performance biosurfactants under extreme reservoir conditions. This study, therefore, developed and optimized a hyperactive mutant strain of a novel Acinetobacter species isolated from reservoir formation water. To enhance its temperature, pH and salinity tolerance along with metabolic yield, the wild-type strain isolatedfrom formation water was subjected to Atmospheric and Room Temperature Plasma (ARTP) using a helium plasma jet at a radio-frequency input power of 120 W. Exposure for 30 seconds resulted in a cellular lethality rate of 90.08% and yielded a positive mutation rate of 60%. Thermal stability evaluations across a temperature range of 45–95 °C over10 days were assessed based on maximum Optical Density (OD) 550nm, emulsification indices (E24, E72), Oil Displacement Test (ODT), Surface Tension (ST), and Interfacial Tension (IFT) dynamics. The selected hyper-producing isolate was subsequently subjected to multi-objective numerical optimization to evaluate its yield limits across varying pH (7.20–10.52) and salinity (15–35%) levels under extreme thermal stress (95 °C). The Biosurfactant Yield (BY) of 1.858 mL, ODT of 7.985 mm, ST of 49.985 dyne/cm, IFT of 41.362 dyne/cm, and emulsification indices of 20.533% E24, 11.955% E48, and 6.568% E72 were obtained. The ARTP mutagenesis provides a highly efficient strategy for generating robust, stress-tolerant bio-agents for tertiary oil recovery applications.