FIG. 7.

Proposed pathway for the initial reactions involved in MTBE oxidation by propane-grown cells of M. vaccae JOB5. The figure shows the proposed pathway for the initial reactions involved in MTBE oxidation by propane-grown cells of M. vaccae JOB5. The structures of hypothesized transient intermediates and other undetected products are in normal type, whereas structures of detected products are in boldface. The reactions with filled arrows were characterized during this study and represent the proposed dominant pathway of MTBE oxidation. The putative enzymes responsible for each reaction are in italics (SCAM = short-chain alkane monooxygenase; EST = esterase). Reactions with hash-marked arrows are predicted but uncharacterized reactions. The putative enzymes responsible for each of these reactions are also in italics (ADH = alcohol dehydrogenase; FDH = formate dehydrogenase). Open arrows represent either abiotic reactions or possible alternative reactions. The reaction arrow marked with an X indicates reactions for which no evidence was obtained. The three thick horizontal lines on the bottom beside C₂H₂ indicate reactions that are sensitive to complete inhibition by acetylene (10% [vol/vol], gas phase).