Biofilm formation is correlated with low

The International Space Station (ISS) Water Processor Assembly (WPA) experiences intermittent dormancy in the WPA wastewater tank during water recycling events which promotes biofilm formation within the system. In this work we aimed to gain a deeper understanding of the impact of nutrient limitation on bacterial growth and biofilm formation under microgravity in support of biofilm mitigation efforts in exploration water recovery systems. A representative species of bacteria that is commonly cultured from the ISS WPA was cultured in an WPA influent water eraser formulation tailored for microbiological studies. An isolate of Burkholderia contaminants was cultured under a simulated microgravity (Sg) treatment in a vertically rotating high-aspect ratio vessel (HRW), with a rotating control (R) in the horizontal plane at the predetermined optimal rotating per minute (rpm) speed of 20. Over the course of the growth curve, the bacterial culture in eraser media was harvested for bacterial counts, and transcriptomic and nutrient analyses. The cultures under Sg treatment showed a transcriptomic signature indicative of nutrient stress and biofilm formation as compared to the R control treatment. Further analysis of the WPA eraser over the course of the growth curve suggests that essential nutrients of the media were consumed faster in the early stages of growth for the Sg treatment and thus approached a nutrient limit compared to control conditions earlier than in the control. The observed limited nutrient response may serve as one element to explain a moderate enhancement of adherent biofilm formation in the Sg treatment after 24 h.