Sterilization of Diesel for Use in Microbial Assimilation Assays on Solid Medium

For in vitro biodegradation studies, hydrocarbons are typically incorporated into culture media. However, the absence of sterilization protocols presents a challenge. The diesel is a non-sterile complex hydrocarbon mixture that is difficult to sterilize using conventional methods. This study aimed to develop a simple and effective method for diesel sterilization that preserves its integrity to allow its use in culture medium. Two sterilization approaches were tested: UV irradiation (15 and 30 min) and filtration through polypropylene membranes. Results showed that UV sterilization of diesel (B7 blend) requires a longer irradiation time, which may alter its chemical composition. Filtration was the most effective method to achieve the sterilization of the hydrocarbon. This technique enabled subsequent diesel assimilation assays. This work proposes an easy-to-implement reproducible sterilization method, which is crucial for accurately assessing microbial degradation and for advancing laboratory-based research in bioremediation. We also proposed diesel as a possible model for studying complex hydrocarbons.