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

Abstract

Abstract

Microbial Enhanced Oil Recovery (MEOR) involves the utilization of microorganisms to improve oil recovery from hydrocarbon reservoirs. The success of MEOR operation is hinge on the selection and utilization of potent microbial organisms capable of producing high-performance biosurfactants under extreme oil reservoir conditions. This study therefore, developed and optimize of 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 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 over 10 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.