Bacterial Microflora of Contaminated Metalworking Fluids

Abstract

ABSTRACTMetal working fluids (MWF) are commonly used in manufacturing and machining industries. There are four major classes of MWF: (i) which contain lubricant base oils without water (straight oils), (ii) composed of an aqueous oil emulsion with oil in high concentration (soluble oils) or (iii) lower concentration (semi-synthetic MWF) and (iv)formulated with no petroleum oils (synthetic fluid). Historically, microbial contamination of metal working fluids has been a problem in the metalworking industries, primarily because of potential adverse health effects and microbial growth effects on fluid quality and performance. Metalworking fluids are chemically complex mixtures. Such mixtures render MWFs potentially toxic to the environment. One solution to the disposal problem is on-site biological treatment of waste MWFs, using bioreactor systems. Bioaugmentation with selected strains may improve the opportunity to create more reproducible system.In this study the bacterial microflora of soluble oil and synthetic metalworking fluid in-use was quantified, isolated and tentatively identified. An indicator plates for dehydrogenase activity were used in attempt to demonstrate the potential of bacteria isolated from contaminated metalworking fluids to utilize hydrocarbons—a component of MWFs.