1 Enrichment of Novel Actinomycetales and the Detection of Monooxygenases during 2 Aerobic 1,4-Dioxane Biodegradation with Uncontaminated and Contaminated Inocula 3 4 5 6 Vidhya Ramalingam and Alison M. Cupples* 7 8 9 Department of Civil and Environmental Engineering, Michigan State University, East Lansing, 10 Michigan, USA 11 12 13 14 *Corresponding Author: 15 Alison M. Cupples 16 A135, 1449 Engineering Research Court, Michigan State University, East Lansing, MI 48824, 17
[email protected] 18 19 20 21 KEYWORDS: 1,4-dioxane, soluble di-iron monooxygenases, Nocardioides, Gordonia, 22 Kribbella, prmA, tomA3 23 Page 1 of 22 24 Abstract 25 1,4-dioxane, a co-contaminant at many chlorinated solvent sites, is a problematic groundwater 26 pollutant because of risks to human health and characteristics which make remediation 27 challenging. In situ 1,4-dioxane bioremediation has recently been shown to be an effective 28 remediation strategy. However, the presence/abundance of 1,4-dioxane degrading species across 29 different environmental samples is generally unknown. Here, the objectives were to identify 30 which 1,4-dioxane degrading functional genes are present and which genera may be using 1,4- 31 dioxane and/or metabolites to support growth across different microbial communities. For this, 32 laboratory sample microcosms and abiotic control microcosms (containing media) were 33 inoculated with four uncontaminated soils and sediments from two contaminated sites. Live 34 control microcosms were treated in the same manner, except 1,4-dioxane was not added. 1,4- 35 dioxane decreased in live microcosms with all six inocula, but not in the abiotic controls, 36 suggesting biodegradation occurred.