Beta-D-fructofuranosidase production by a 2-deoxy-D-glucose stabilized mutant strain of Saccharomyces cerevisiae on kinetic basis
2006
Ikram-ul-Haq (Government Coll. Univ., Lahore (Pakistan). Biotechnology Research Centre) | Ali, S. (Government Coll. Univ., Lahore (Pakistan). Biotechnology Research Centre) | Aslam, A. | Qadeer, M.A.
The present study deals with the beta-D-fructofuranosidase production by a 2-deoxy-D-glucosc resistant mutant strain of Saccharomyces cerevisiae on kinetic basis. For this purpose, the wild-culture (Saccharomyces cerevisiae IS-14) was developed by combined treatments of radiations and chemicals (UV/MNNG, UV/EMS, MNNG/EMS) for different time intervals (10-30 min). The best beta-D- fructofuranosidase mutant strain of Saccharomyces cerevisiae (34.12 U/ml) was coded to as UME-2. This mutant strain was cultured on the medium containing 2-deoxy D- glucose (2dg) and its stability for beta-D-fructofuranosidase productivity was determined at various 2dg levels. The 2dg concentration of 0.04 mg/ml was found optimal, as at this level UME-2 gave consistent beta-D-fructofuranosidase yield. After optimization of incubation time (48 h), sucrose concentration (5.0 g/I), initial pH (6.0) and 16 h old inoculum (size 2.0 %, v/v), enzyme production reached 45.65 U/ml with a noticeable = 40-fold increase compared to the original wild-culture (IS-14). On the basis of kinetic parameters notably Qp (0.723 U/g/h), Yp/s (2.036 U/g) and Qp (0.091 U/g yeast cells/h), it was concluded that the mutant (UME-2) is a hyper producer of beta-D- fructofuranosidase and has a faster growth rate. The over all rate of volumetric productivity is 31.43 fold improved over the parental strain and economically highly significant (LSD 0.054, p less than 0.05).
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