Identification and Characteristics of a Fungal Contaminant in Naphthenic Metal Working Fluid

microbial contamination;metal working fluid;fungal contamination;Penicillium;College of Arts and Sciences: Biology

Cossaboom, Russell M.Flint ;

University of Michigan

关键词: microbial contamination;    metal working fluid;    fungal contamination;    Penicillium;    College of Arts and Sciences: Biology;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/117691/Cossaboom.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Microbial contamination of metalworking fluids is an ongoing problem. The fluid provides nutrients and thus the mocrobes degrade the emulsion oil fluid. Samples were obtained from a metal fabrication factory that was experienceing intermittent contamination and fouling of machinery with the resulting biofilm. The funal contaminant was isolated and then identified by morphological characteristics based on the Saccardo System of Classification. Morphological characteristics were observed with two approaches, light and scanning electron microscopies. The fungal contaminant was identified as Penicillium. Culture tubes of naphthenic metalworking fluid were incolulated with a sterile loop of conidia. The fluid was preared as one part oil to six parts sterile municipal water for incubation periods, 2, 3, 4, and 5 weeks at 23 degrees Celcius and 37 degrees Celcius. The interaction between the metalworking fluid and fungal contaminant was characterized by gas chromatography. The gas chromatograph curves were digitized into area sthat corresponded to boiling point fractins of standard alkanes. Gas chromatographs showed unique peak differences between culture samples of different ages and termperatures. The boiling point fraction of 60-110 degrees Celcius contained unique peaks that were observed with Penicillium and occurred as early as two weeks of age. The fungal cultures showed decreases in the relative percent of the areas of the gas chromatograph in higher boiling point fractions, by the age of 5 weeks. These fungal chemical byproducts found in the 60-100 degrees Celcius fraction correspond to compounds of 6-10 carbon atoms. This research demonstrates that Penicillium can grow in naphthenic metalworking fluid and thus, alter the chemical composition of that fluid.