Figure 2 (IMAGE) Tokyo Institute of Technology Caption Typical samples analyzed in the study. Left-hand side: Incubation of bacteria with propane. Right-hand side: Natural gas sample. Credit N. Escanlar/ELSI Usage Restrictions The image may only be used with appropriate caption or credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.