Establish a Bench-Scale System for Studying Metalworking Fluids Associated Biofilms

Research Trainee: Jianfeng Wu, PhD, Postdoctoral Fellow, Dept. of Environmental Health Sciences at the University of Michigan

Faculty Researcher: Chuanwu Xi, PhD, Assistant Professor of Environmental Health Sciences at the University of Michigan

Metal removal fluids (MRFs) are used to reduce heat and friction and to improve product quality in industrial machining and grinding operations. However, water-based metal removal fluids support microbial growth, which introduces biological contaminants (such as bacterial and fungal cells or cell components and their related biological byproducts such as endotoxins, exotoxins, and mycotoxins). In 1993 the first cases of hypersensitivity pneumonitis (HP) in relation to metal removal fluids were reported. Since then there have been approximately 20 reported outbreaks involving hundreds of cases, with strong evidence that the causative agent (or agents) is microbial contamination of the fluids. Recently, a newly identified organism, Mycobacterium immunogenum (MI), has been reported have an etiologic role in hypersensitive pneumonitis (HP) associated with the exposure to MRFs. Our previous research, supported by the University of Michigan Center for Occupational Health and Safety Engineering (UM-COHSE), a National Institute for Occupational Safety and Health (NIOSH) funded Education and Research Center (ERC), revealed that the microbial community in MRFs system contained a broad diversity of microbes, including Mycobacteria. It was more interesting that Mycobacteria (more specifically MI) were found in all biofilm samples. This finding strongly support our hypothesis that biofilms play a very important role in microbial ecology in MRFs, which may provide a shield or sheltered microenvironment for the growth of Mycobacteria and act as seeding sources for circulating MRFs. In this pilot project, we will establish a bench-scale bioreactor system to monitor biofilm development in MWFs and evaluate the efficacy of several intervention approaches for controlling biofilm development and Mycobacteria growth in MWFs and its associated biofilms. Meanwhile, an ongoing project on the screening a collection of 56,000 chemicals for small compounds that inhibit specially biofilm formation and growth has been initiated in Dr. Xi’s lab; we will test the efficacy of several compounds identified from that project on the biofilm formation and growth in MWFs using the bench-scale bioreactor. This project will permit research and research training among the following NORA focus areas: 1) Infectious Diseases; 2) Indoor Environments; 3) Exposure Assessment Methods.


Publications resulting from this project:
Wu, J., Franzblau, A., and Xi, C. (2016). Molecular characterization of microbial communities and quantification of Mycobacterium immunogenum in metal removal fluids and their associated biofilms. Environmental science and pollution research international 23, 4086-4094.

Grants resulting from this project:
NIOSH/CDC. 5R01 OH009306-02. Prospective Study of Biofilms, Mycobacteria and Pseudomonads in Metalworking Fluids (PI: Xi). 2009-2012.

Research trainee’s current position:
Jianfeng Wu is currently a Research Investigator in the Dept. of Environmental Health Sciences at the University of Michigan.