Kinetics of an extracellular β-D-fructofuranosidase fructohydrolase production from a derepressed mutant of Saccharomyces carlsbergensis and parameter significance analysis by 2-factorial design

In the present study,over hundred strains of saccharomyces carlsbergensis were isolated from various fruits including jaman,plum,peach,date,banana and mango. these isolates were screened for extracellular β-d- fructofuranosidase fructohydrolase (ffh) production under submerged fermentation (smf). the strain gcbt-99 isolated from plum gave relatively better enzyme activity and it was exposed to ultraviolet radiations (uv dose ∼1.2×10 j/m2/s) to improve its ffh potential. among 16 uv irradiated mutant strains,uv-dg4 was selected for batch culture optimizations as it exhibited ∼17.86 fold higher enzyme activity compared to wild culture. the potential mutant was cultured overnight and plated on yps-agar medium containing various levels of 2-deoxy-d-glucose (2dg). the cultural conditions and nutritional requirements were optimized in a stirred fermentor by the selected mutant culture. over 75% enhancement in enzyme production (38.72 u/ml/min) on the basis of substrate consumption was achieved when the process parameters including sucrose concentration (10 g/l),incubation period (72 h),initial ph (6),inoculum size (12%,v/v) and soybean meal as a nitrogen source (5 mg/ml nitrogen) were further identified using plackett-burman design (pbd) and response surface methodology (rsm). on the basis of kinetic variables,notably qp (0.826 u/ml/h),yp/s (2.845 u/ml/g) and qp (0.102 u/g yeast cells/h),the mutant uv-dg4 was found to be a hyper ffh producer (p≤0.05) indicating a viable utility (hs,lsd∼0.031). copyright 2013 zoological society of pakistan.