Adenylate Energy Charge-New Tool for Determining Metalworking Fluid Microbial Population’s Sublethal Response to Microbicide Treatment | Biomedgrid

Adenylate energy charge (AEC) is computed from the ratios of three energy molecules found in all living cells: adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP). Previous studies have shown that when microbicide treatments resulting in ATP concentration decreases of <2Log10 pg ATP mL-1, populations recover within a few days post-treatment. Recovery has not been observed when microbicide treatments reduce ATP-bioburdens by <2Log10 pg ATP mL-1. However, frequently <1 Log10 pg ATP mL-1 remains even after effective treatment. The AECs of robust microbial communities range from 0.7 to 0.95. When populations are stressed, the AEC decreases – reflecting the relative depletion of ATP and accumulation of ADP and AMP within cells. The paper reports the impact of lethal and sub-lethal microbicide treatments on AEC in microbially contaminated emulsifiable oil and semi-synthetic metalworking fluids. The results demonstrate the utility of AEC testing to determine the physiological state of microbial contaminants in water-miscible metalworking fluids. This capability is becoming increasingly important as metalworking fluid move from microbicide use to reliance on bio resistant functional additives.