Abstract: Hydrocarbon-contaminated soils are important reservoirs of biosurfactant-producing bacteria due to the selective pressure exerted by petroleum pollutants on indigenous microbial communities. Biosurfactants are surface-active compounds produced by microorganisms and have gained considerable attention because of their applications in environmental remediation and various industrial processes. This study aimed to isolate and screen biosurfactant-producing bacteria from hydrocarbon-contaminated soils collected from automobile mechanic workshops in Sokoto Metropolis, Nigeria. Soil samples were collected from three contaminated sites and analyzed using standard physicochemical and microbiological methods. Aerobic heterotrophic bacterial counts ranged from 2.5 × 10⁷ to 1.38 × 10⁸ CFU/g across the sampling locations. A total of sixteen bacterial isolates were recovered and identified as Pseudomonas aeruginosa, Bacillus subtilis, Bacillus pumilus and Staphylococcus epidermidis. Biosurfactant production was screened using haemolysis, drop collapse and oil displacement assays, while emulsification activity was used to evaluate selected isolates. Eight isolates showed positive haemolytic activity, five were positive for the drop collapse test and eight exhibited oil displacement activity. Among the identified isolates, Pseudomonas aeruginosa and Bacillus subtilis demonstrated the strongest biosurfactant-producing potential based on their performance in the screening assays and emulsification activity. The findings indicate that hydrocarbon-contaminated soils in Sokoto Metropolis harbour indigenous bacteria with promising potential for biosurfactant production and possible application in bioremediation of petroleum-contaminated environments. Further studies on molecular characterization and optimization of biosurfactant production are recommended. Keywords: Biosurfactants; hydrocarbon-contaminated soil; Pseudomonas aeruginosa; Bacillus subtilis; bioremediation. Title: Isolation and Screening of Biosurfactant-Producing Bacteria from Hydrocarbon-Contaminated Mechanic Workshop Soils in Sokoto Metropolis, Nigeria Author: Asiya Gidado Yabo, Sakina Abubakar Gatawa International Journal of Novel Research in Life Sciences ISSN 2394-966X Vol. 13, Issue 3, May 2026 – June 2026 Page No: 1-7 Novelty Journals Website: www.noveltyjournals.com Published Date: 03-June-2026 DOI: https://doi.org/10.5281/zenodo.20525007 Paper Download Link (Source) https://www.noveltyjournals.com/upload/paper/Isolation%20and%20Screening%20of%20Biosurfactant-03062026-3.pdf