We determined that a UV-C irradiance of >5-10 mW/cm2 controls biofilm accumulation on surfaces. Lower UV-C intensities appear to be ineffective in curtailing the growth of biofilms. Insufficient sublethal UV-C exposure led to upregulation genes for SOS response and quorum sensing as survival strategies against UV-C stress. These results underscore the need to maintain minimum UV-C exposure on surfaces to effectively inhibit biofilm formation in water systems. On the basis of this work, more future research is needed to understand the behavior of light within different components of live/dead bacteria but also within EPS, proteins, and other materials potentially present in biofilms. The dynamic nature of biofilms and their response to low levels of UV-C light are potentially one of the most critical areas for future research.
A recent collaboration between NEWT institutes at Arizona State University and Rice University; Biodesign Swette Center for Environmental Biotechnology, Arizona; and Advanced interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhuhai, China.
Collaborative cross-campus efforts (left to right) by authors: Zhe Zhao, Yi-Hao Luo, Shahnawaz Sinha, Bruce Rittmann, Pedro Alvarez (Rice University), François Perreault, and Paul Westerhoff of Arizona State University. Tzu-Heng Wang and Li Ling are not pictured.