Exploring the Potential and Evaluating Hydrocarbon Degradation by Novel Antarctic <i>Dietzia</i> and <i>Pusillimonas</i> Isolates From a Pristine Environment

This study evaluated the bioremediation potential of two psychrotolerant strains, Pusillimonas sp. ANT_WB101 and Dietzia sp. ANT_WB102, isolated from an uncontaminated water pond. Comparative analysis indicated affinities with P. gingsengisoli/soli and D. kunjamensis/maris. Both strains demonstrated substantial crude oil degradation efficiency, achieving ≥ 79% under aerobic conditions and ≥ 34% under anaerobic conditions. Genomic analysis identified crucial genes involved in crude oil degradation, including alkane monooxygenase, cytochrome P450, and polyphenol monooxygenase. These strains displayed adaptability to a wide range of environmental factors, such as pH (4-11), salinity (up to 6%-9%), temperature (4°C-37°C), resistance to freeze-thaw cycles, and tolerance to high crude oil concentration. Biosafety evaluations indicated the sensitivity of the strains to various antibiotics, ensuring their suitability and safety for environmental applications. At low temperature, these strains increased microbial activity in environmental samples (1.34 times in biological oxygen demand compared to the control) and showed effective biodegradation (~39%). In conclusion, the study highlights the potential of ANT_WB101 and ANT_WB102 for treating contaminated sites and indicates the possible challenges of using microorganisms not initially adapted to site-specific conditions in bioremediation efforts.