@article{bealessio_chen_krippaehne_murnane_hyman_semprini_2023, title={Alcohol-Dependent Cometabolic Degradation of Chlorinated Aliphatic Hydrocarbons and 1,4-Dioxane by Rhodococcus rhodochrous strain ATCC 21198}, volume={8}, ISSN={["1557-9018"]}, DOI={10.1089/ees.2023.0058}, abstractNote={Resting cell batch kinetic studies were performed to evaluate the alcohol-dependent cometabolic degradation of chlorinated aliphatic hydrocarbons (CAHs) and 1,4-dioxane (1,4-D) by Rhodococcus rhodochrous strain ATCC 21198. This strain grew on diverse alcohols, organic acids, esters, and other organic compounds. Only growth on 2-butanol resulted in labeling of monooxygenase enzymes and the ability to oxidize propylene, the cylic ether 1,4-D, and its close structural analog tetrahydrofuran. In single compound rate tests, 2-butanol-grown cells exhibited faster degradation rates for less chlorinated compounds. The rates of degradation are ranked as follows from high to low: vinyl chloride > cis-dichloroethene (cis-DCE) >1,1-dichoroethane >1,1-dichoroethene (1,1-DCE) >1,4-D > 1,1,1-trichoroethane (1,1,1-TCA) >1,1,2-trichoroethene. All rates were significantly lower than isobutane-grown cells. 2-Butanol-grown cells exhibited a lag period before cometabolic degradation of most CAHs, including cis-DCE; however, production of cis-1,2-dichloro-1,2-epoxyethane (cis-DCE epoxide) was detected with no lag. Cells grown on 1-butanol, 2-butanol, or 2-ethyl-1-butanol also cometabolically degraded 1,4-D and various CAHs. However, compared to cells grown on 1-butanol or 2-ethyl-1-butanol, cells grown on 2-butanol had a larger transformation capacity and faster degradation rates and were able to fully degrade (>99% removal) a mixture of 1,4-D, cis-DCE, and 1,1,1-TCA. With CAH mixtures, alcohol-grown cells degraded cis-DCE faster than both 1,1,1-TCA and 1,4-D. sec-Butyl-acetate (sBA) was demonstrated as a potential slow-release substrate that hydrolyzes to yield 2-butanol and acetate. Cells grown on this ester degraded a mixture of 1,1,1-TCA and 1,4-D at rates faster than 2-butanol-grown cells. The cometabolic transformation of 1,1,1-TCA and 1,4-D was also observed in reactors where growth occurred with sBA as the growth substrate.}, journal={ENVIRONMENTAL ENGINEERING SCIENCE}, author={Bealessio, Alisa D. D. and Chen, Weijue and Krippaehne, Krysta J. J. and Murnane, Riley A. A. and Hyman, Michael R. R. and Semprini, Lewis}, year={2023}, month={Aug} }
 @article{chen_faulkner_smith_fruchte_hyman_2021, title={Draft Genome Sequences of Four Aerobic Isobutane-Metabolizing Bacteria}, volume={10}, ISSN={["2576-098X"]}, url={https://doi.org/10.1128/MRA.01381-20}, DOI={10.1128/MRA.01381-20}, abstractNote={Here, we report the draft genome sequences of four aerobic gaseous alkane-oxidizing bacteria isolated from soil by enrichment culture using isobutane (2-methylpropane) as the sole carbon and energy source. The sequences all reveal microorganisms with multiple alkane-oxidizing monooxygenases, including soluble di-iron monooxygenases (SDIMOs), copper-containing monooxygenases (CuMMOs), and alkane hydroxylases (AHs).}, number={18}, journal={MICROBIOLOGY RESOURCE ANNOUNCEMENTS}, publisher={American Society for Microbiology}, author={Chen, Weijue and Faulkner, Nicholas and Smith, Christy and Fruchte, Megan and Hyman, Michael}, editor={Maresca, Julia A.Editor}, year={2021}, month={May} }
 @article{murnane_chen_hyman_semprini_2021, title={Long-term cometabolic transformation of 1,1,1-trichloroethane and 1,4-dioxane by Rhodococcus rhodochrous ATCC 21198 grown on alcohols slowly produced by orthosilicates}, volume={240}, ISSN={["1873-6009"]}, DOI={10.1016/j.jconhyd.2021.103796}, abstractNote={Long-term cometabolic transformation of 1,1,1-trichlorethane (1,1,1-TCA) and 1,4-dioxane (1,4-D) was achieved using slow release compounds (SRCs) as growth substrates for pure cultures of Rhodococcus rhodochrous ATCC 21198 (ATCC strain 21198). Resting cell transformation tests showed 1,4-D transformation occurred without a lag phase for cells grown on 2-butanol, while an induction period of several hours was required for 1-butanol grown cells. These observations were consistent with activity-based labeling patterns for monooxygenase hydroxylase components and specific rates of tetrahydrofuran (THF) degradation. 1,1,1-TCA and 1,4-D degradation rates for alcohol-grown cells were slower than those for cells grown on gaseous alkanes such as isobutane. Batch metabolism and degradation tests were performed, in the presence of 1,1,1-TCA and 1,4-D, with the growth of ATCC strain 21198 on alcohols produced by the hydrolysis of orthosilicates. Three orthosilicates were tested: tetrabutylorthosilicate (TBOS), tetra-s-butylorthosilicate (T2BOS), and tetraisopropoxysilane (T2POS). The measured rates of alcohol release in poisoned controls depended on the orthosilicate structure with TBOS, which produced a 1° alcohol (1-butanol), hydrolyzing more rapidly than T2POS and T2BOS, that produced the 2° alcohols 2-butanol and 2-propanol, respectively. The orthosilicates were added as light non-aqueous phase liquids (LNAPLs) with ATCC strain 21198 and formed dispersed droplets when continuously mixed. Continuous rates of oxygen (O2) consumption and carbon dioxide (CO2) production confirmed alcohol metabolism by ATCC strain 21198 was occurring. The rates of metabolism (TBOS > T2POS > T2BOS) were consistent with the rates of alcohol release via abiotic hydrolysis. 1,4-D and 1,1,1-TCA were continuously transformed in successive additions by ATCC strain 21198 over 125 days, with the rates highly correlated with the rates of metabolism. The metabolism of the alcohols was not inhibited by acetylene, while transformation of 1,4-D and 1,1,1-TCA was inhibited by this gas. As acetylene is a potent inactivator of diverse bacterial monooxygenases, these results suggest that monooxygenase activity was required for the observed cometabolic transformations but not for alcohol utilization. Alcohol concentrations in the biologically active reactors were maintained below the levels of detection, indicating they were metabolized rapidly after being produced. Much lower rates of O2 consumption were observed in the reactors containing T2BOS, which has benefits for in-situ bioremediation. The results illustrate the importance of the structure of the SRC when developing passive aerobic cometabolic treatment systems.}, journal={JOURNAL OF CONTAMINANT HYDROLOGY}, author={Murnane, Riley A. and Chen, Weijue and Hyman, Michael and Semprini, Lewis}, year={2021}, month={Jun} }