Partial characterization of proteases from Spretomyces clavuligerus using an inexpensive medium

The partial characterization of extracellular proteases from Streptomyces clavuligerus NRRL 3585 and 644 mutant was investigated. The enzyme production was carried out in batch fermentation using soy bean filtrate as nitrogen source. Maximum activity was obtained after 96h of fermentation with an initial pH of 7.0. The enzyme was partially purified by ammonium sulphate precipitation. Enzymes from the two strains retained 37 per cent of their initial activities at pH 8.0 after 2 h incubation at 25§C. Enzyme half-life at pH 8.0 and 60§C was 40.30 and 53.32 min, respectively for both strains (partially purified extract). The optimum pH was obtained at pH 7.0-8.0 and 8.4 for enzymes produced for 3585 and 644 strains (crude extract), respectively, and 8.4 and 8.0 for enzymes from the partially purified extract 3585 and 644 strains, respectively. The optimum temperature for the crude extract was 21§C for both strains. However, for the partially preparation the optimum temperature was 50§C and 40ºC for S. clavuligerus NRRL 3585 and 644 strains respectively.

Production of extracellular lipase by the phytopathogenic fungus "Fusarium solani" FS1

A Brazilian strain of "Fusarium solani" was tested for extracellular lipase production in peptone-olive oil medium. The fungus produced 10,500 U.L(E-1) of lipase after 72 hours of cultivation at 25ºC in shake-flask at 120rpm in a medium containing 3(per cent) (w/v) peptone plus 0.5(per cent)(v/v) olive oil. Glucose (1(per cent) w/v) was found to inhibit the inductive effect of olive oil. Peptone concentrations below 3(per cent)(w/v) resulted in a reduced lipase production while increased olive oil concentration (above o.5(per cent)) did not further stimulate lipase production. The optimum lipase activity was achieved at pH 8.6 and 30ºC and a good enzyme stability (80(per cent) activity retention) was observed at pH ranging from 7.6 to 8.6, and the activity rapidly dropped at temperatures above 50ºC. Lipase activity was stimulated by addition of n-hexane to the culture medium supernatatnts, in contrast to incubation with water-soluble solvents