ABSTRACT
A commercial metalworking fluid, 5% stock solution/95 % deionized water, was found to contain multiple microbial species including bacteria, most probably Actinobacter, Pseudomonas, Aerobacter and Bacillus, and fungi. Bacterial concentrations in the metalworking fluid increased with decreasing temperature (5.0 × 107 @ 50%C and 2.5 × 108 @ 37%C). The bacterial population was capable of using all the stock solution components as substrates. However, fatty acids and fatty acid esters were metabolized at a much greater rate than the other components due to the ease of the β-oxidation metabolism of these components. Rates of biological growth decreased with increasing temperature.
