Sensitivity of Microbial Lipases to Antibiotics

Abstract

A study was conducted to determine the effect of various concentrations of pimaricin, mycostatin, and penicillin upon bacterial and fungal lipases. Although the antibiotics exhibited extremely mild inhibitory effects upon the cell production of Achromobacter lipolyticum, the lipase activity of the growing culture was arrested by 46 to 100%, 59 to 100%, and 43 to 100% by 0.5 to 50.0 units of pimaricin, mycostatin, and penicillin per milliliter, respectively. Different concentrations of the antibiotics inhibited the lipases produced by A. lipolyticum, Geotrichum candidum, Aspergillus niger, and Penicillium roqueforti to varying degrees. There was a direct but not proportional relationship between the antibiotic concentration and the per cent inhibition. The fungal lipase of G. candidum showed maximum resistance to antibiotic action. Under the conditions of the study, A. lipolyticum, produced considerably more lipase or at a faster rate than those produced by the fungi. While A. lipolyticum and G. candidum produced only extracellular lipases, A. niger and P. roqueforti produced both intra- and extra-cellular lipases. The antibiotics appeared to have no specificity in regard to the inhibition of intra- or extra-cellular mold lipases. An increase in the substrate concentration in the experimental mixture nullified the inhibitory effect of the antibiotics upon the microbial lipases, indicating that the antibiotics are competitive inhibitors.