Evaluation of biofilm formation by bacteria isolated from engine oil-contaminated soil and exploring its bioremediation potential in vitro

• Published in: Journal of the Indian Chemical Society 2024-09, Vol.101 (9), p.101249, Article 101249
• Main Authors: Rai, Chaithra J., Prakash, Bharathi, Girisha, S.K., Khedkar, G.D., Kushala, K.B., Murthy, H.C. Ananda
• Format: Article
• Language: English
• Subjects: 16s RNA sequencing; Bioremediation; Klebsiella quasipneumoniae; Microtiter plate; Stutzerimonas stutzeri; Tube adherence test
• ISSN: 0019-4522
• DOI: 10.1016/j.jics.2024.101249

This study investigated the biofilm-forming ability of bacteria isolated from engine oil-contaminated soil and assessed their potential for bioremediation. Fifteen engine oil contaminated soil samples were collected and inoculated into Bushnell-Haas (BH) broth supplemented with 2 % engine oil. After incubation, bacterial colonies were isolated and identified using 16s RNA sequencing. The tube adherence test also known as Christensen method and modified microtiter plate quantification of biofilm formation by Stepanović et al. (2000) [1], was used to study bacterial biofilm as tube test and the microtiter-plate test are the most frequently used techniques for quantifying biofilm formation was used to study bacterial biofilm. Both quantitative (OD measurements) and qualitative (visual observation) methods were employed, classifying the six isolates into three categories: strong, moderate, and low biofilm producers. Among the 6 bacterial isolates, Stutzerimonas stutzeri exhibited the highest biofilm-forming ability. Oil degradation capacity of the isolates were tested individually as monocultures and co-cultures with other isolates. Results showed that the co-culture of Stutzerimonas stutzeri and Klebsiella quasipneumoniae showed significantly higher oil degradation compared to their monoculture and other co-cultures, suggesting synergistic interactions between the two bacterial species. However, Stutzerimonas stutzeri alone exhibited good oil degradation potential and is more useful for bioremediation but Klebsiella quasipneumoniae's rare pathogenicity, may not be suitable for field application. This study highlights biofilm-forming bacteria, particularly Stutzerimonas stutzeri, as a potential solution for bioremediating engine oil-contaminated sites. [Display omitted] •Stutzerimonas stutzeri exhibited superior biofilm formation among tested isolates, indicating strong adhesion potential.•Stutzerimonas stutzeri achieved the highest individual oil degradation (0.38 g), demonstrating its bioremediation capacity.•The co-culture of Stutzerimonas stutzeri and Klebsiella quasipneumoniae exhibited a 26.32 % increase in oil degradation.•Combining bacteria with complementary strengths leads to superior bioremediation efficiency compared to individual strains.