Spatiotemporal dynamic changes in the microbiota in a front-loading household washing machine

Household washing machines (WMs) often form annoying biofilm and produce unpleasant smell, which are mainly caused by microbial fouling. In this work, the spatiotemporal dynamic changes in the microbiota of a WM after one year of operation were determined in the biofilms on the rubber door seal and the inside wall of the outer drum. Results showed that the main bacterial species in the WMs were Acinetobacter, Sphingobium, Pseudomonas, and Chryseobacterium, while the main fungi were Meyerozyma guilliermondii and Rhodotorula mucilaginosa. The typical microorganisms were isolated and identified. When cultivated in a medium containing laundry wastewater, Acinetobacter junii and Pseudomonas putida produced abundant dimethyl disulfide. Pseudomonas putida and M. guilliermondii were resistant to Ag+. The dominant microorganisms were classified for each season, and the mechanism of microorganism colonization and odor production in the WMs was proposed.