Abstract
Oil contamination in arid regions poses significant environmental challenges under high salinity and extreme temperatures. This study investigated bioremediation performance of free and carrier-immobilized bacterial consortia (Rhodococcus erythreus AT7 and Dietzia maris 22K) under varying temperature (+4°C, +32°C, +42°C) and salinity conditions (3%, 5%, 10% NaCl; 0.5%, 1% MgSO₄). Strains were immobilized on agricultural waste carriers (buckwheat and rice husks) using adsorption method. Rice husk-immobilized bacteria demonstrated superior oil degradation, achieving 78.4±0.89% efficiency under extreme stress (10% NaCl, +42°C) versus 37.2±0.95% for free cells. Optimal temperature (+32°C) enhanced degradation rates, with immobilized systems maintaining 75.0-83.0% efficiency under high salinity. Temperature elevation to +42°C severely impacted free cell viability (5.1 log CFU/g) while immobilized systems maintained higher densities (6.9 log CFU/g). Results demonstrate that agricultural waste-based immobilization significantly enhances microbial stress tolerance and bioremediation efficiency, offering practical solutions for petroleum contamination treatment under extreme environmental conditions. Field validation is required before practical application.