J.B. Risatti M. Schoell D.D. Coleman 1981 <div id="preview-section-abstract"><div id="abstracts" class="Abstracts u-font-serif text-s"><div id="aep-abstract-id6" class="abstract author"><div id="aep-abstract-sec-id7"><p>Carbon isotopic analysis of methane has become a popular technique in the exploration for oil and gas because it can be used to differentiate between thermogenic and microbial gas and can sometimes be used for gas-source rock correlations. Methane-oxidizing bacteria, however, can significantly change the carbon isotopic composition of methane; the origin of gas that has been partially oxidized by these bacteria could therefore be misinterpreted.</p><p>We cultured methane-oxidizing bacteria at two different temperatures and monitored the carbon and hydrogen isotopic compositions of the residual methane. The residual methane was enriched in both<span>&nbsp;</span>¹³C and D. For both isotopic species, the enrichment at equivalent levels of conversion was greater at 26°C than at 11.5°C. The change in δD relative to the change in δ¹³C was independent of temperature within the range studied. One culture exhibited a change in the fractionation pattern for carbon (but not for hydrogen) midway through the experiment, suggesting that bacterial oxidation of methane may occur via more than one pathway.</p><p>The change in the δD value for the residual methane was from 8 to 14 times greater than the change in the δ¹³C value, indicating that combined carbon and hydrogen isotopic analysis may be an effective way of identifying methane which has been subjected to partial oxidation by bacteria.</p></div></div></div></div> application/pdf 10.1016/0016-7037(81)90129-0 en Elsevier Fractionation of carbon and hydrogen isotopes by methane-oxidizing bacteria article