bioRxiv preprint doi: https://doi.org/10.1101/2021.08.30.458270; this version posted August 31, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 Global distribution of anaerobic dichloromethane degradation potential 2 3 Short Title: Anaerobic dichloromethane biodegradation 4 5 Robert W. Murdoch1†, Gao Chen1,2, Fadime Kara Murdoch1,7†, E. Erin Mack5, Manuel I. Villalobos Solis6, 6 Robert L. Hettich6, and Frank E. Löffler1,2,3,4,6* 7 1Center for Environmental Biotechnology, 2Department of Civil and Environmental Engineering, 8 3Department of Microbiology, 4Department of Biosystmes Engineering and Soil Science, University of 9 Tennessee, Knoxville, TN 37996, USA 10 5Corteva Environmental Remediation, Corteva Agriscience, Wilmington, DE 19805, USA 11 6Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA 12 † Current address: Battelle Memorial Institute, Columbus, Ohio 43201 13 * Corresponding author: Frank E. Löffler. Center for Environmental Biotechnology, 14 University of Tennessee, 676 Dabney Hall, 1416 Circle Drive, Knoxville, TN 37996-1605, USA 15 Phone: (865) 974 4933 Email:
[email protected] 16 Competing Interest Statement: The authors declare no competing interest. 17 Classification: Biological Sciences (Major); Environmental Sciences (Minor) 18 Keywords: Dichloromethane fluxes, Degradation Potential, Bioremediation, Ozone Destruction 19 Abstract 20 Anthropogenic activities and natural processes release dichloromethane (DCM), a toxic chemical with 21 substantial ozone-depleting capacity. Specialized anaerobic bacteria metabolize DCM; however, the 22 genetic basis for this process has remained elusive. Comparative genomics of the three known 23 anaerobic DCM-degrading bacterial species revealed a homologous gene cluster, designated the 24 methylene chloride catabolism (mec) gene cassette, comprising eight to ten genes with predicted 79.6 – 25 99.7% amino acid identity.