AUTOLYSIS OF BAKER’S YEAST AND PARTIAL PURIFICATION OF INVERTASE IN THE PRESENCE OF SURFACTANTS
Michele Vitolo *
ABSTRACT
Baker’s yeast cells were suspended in 0.154M NaHCO3 in the presence or absence of surfactants (TWEEN 20, 40, 60, or 80), and shaken at 200 cycles/min at 45oC for 24 h. The suspension was centrifuged (10,000 rpm/20 min) and the supernatant collected (autolyzate). Sodium picrate was added to the autolyzate; after 5h of contact at room temperature, the precipitate formed was separated by centrifugation (10,000 rpm/30 min) and discharged. The supernatant was treated with acetone in the presence or absence of surfactants to precipitate invertase. Invertase activity increased by at least 11% and 25% in the presence of TWEEN-40 and blends of TWEENs, respectively. Precipitation of invertase with acetone was neither affected by HLB nor by surfactant type and concentration. However, HLB and total invertase activity were linearly correlated, indicating that in an emulsified solution, such as aqueous two-phase systems, the use of surfactants could be more effective on the precipitation of invertase with acetone.
Keywords: Invertase, yeast, enzyme purification, autolysis.
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