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Some Characteristics of the Lipase of Geotrichum Candidum

1952; Elsevier BV; Volume: 35; Issue: 5 Linguagem: Inglês

10.3168/jds.s0022-0302(52)93727-2

1529-9066

W.O. Nelson,

Enzyme Catalysis and Immobilization

The conditions necessary for optimum lipase activity vary with the source of enzyme, the substrate and the methods used in obtaining the lipase preparation.Thus, it has been reported (4) that both Aspergillus niger and Penicillium roqueforti produce two types of lipase.The extracellular lipases were most active at pH 8.0, whereas the mycelial lipases exhibited maximum activity at pH 6.5.In addition, the optimum temperature for lipolysis varied with the substrate.Similarly, Tammisto (13) demonstrated that the heat-resistant intracellular lipase of B. jl1w1'escens liquefaciens became heat sensitive when the cells were air-dried.Furthermore, the dried preparations exhibited a lower pH optimum than did the fresh cell preparation.The lipase of Candida lipolytica, characterized by Peters and Nelson ( 7), was active over wide ranges of pH and temperature.Maximum cleavage of butterfat occurred at pH 6.2 to pH 6.5 and at 28 to 33°C.The activity of cellfree preparations was virtually unchanged by storage at 3 to 5°C. for 3 mo.However, considerable activity was lost during lyophilization and foam concentration.The same authors (8) also reported that favorable growth conditions resulted in low lipase production.The accumulation of lipase was enhanced by growing C. lipolytica without shaking and the addition of reducing substances to the cultures had little or no effect on the accumulation of lipase.Although it has been reported that cysteine reverses the inactivation of milk lipase brought about by aeration (6) and that wheat germ lipase requires intact sulfhydryl groups for activity (12), the lipase of some microorganisms may differ in this regard.According to Fiore and Nord (2), the intracellular lipase of Fusarium lini contains no sulfhydryl or disulfide groups essential for activity.Similarly, microbiallipases also may vary in sensitivity to oxygen and other oxidizing agents.In this connection, it has been reported (3) that the lipase of Clostridium perfringens was unaffected by air or 10-2 M H 2 0 2 • Conversely, H 2 0 2 or KBrOg have been added to cultures of Geotrichum candidum during fat synthesis studies (9) to prevent lipolysis of the accumulated fat.Thus, it is apparent that growth and assay conditions directly influence lipase production and activity and, therefore, the behavior of an organism and its lipase in a given situation cannot be predicted.Although G. candidum rapidly hydrolyzes butterfat in cream (5), the characteristics of its lipolytic system are relatively unknown.It is the purpose of this paper to report some of the characteristics of the G. cand'idum lipase.