A fluorimetric method for the determination of Pseudomonas fluorescens AR11 lipase in milk

SUMMARY A method has been developed, using the fluorogenic substrate 4-methylumbelliferyl oleate, to measure the activity of the extracellular lipase of the psychrotroph Pseudomonas fluorescens AR11 in milk. Inhibition of lipolysis by constituents of skim-milk was prevented by including both sodium taurocholate and cetyltrimethylammonium bromide in the reaction mixture. Cream also interfered with the reaction and skim-milk was used for high sensitivity. Natural milk lipase was readily inactivated by heat treatment to which AR11 lipase was relatively resistant.