Optimization of β-galactosidase production by response surface methodology using locally isolated Kluyveromyces marxianus.

Five parameters including initial sugar concentration, agitation speed, initial pH, incubation time and temperature were studied for the optimization of β-galactosidase production in synthetic medium containing lactose as carbon source by Kluyveromyces marxianus DIYS11 and using Response Surface Methodology (RSM) as statistical analysis. The optimum conditions for the highest enzyme activity were sugar concentration = 10%, agitation speed = 250 rpm, pH =3, incubation time = 64 hours and temperature=20˚C which generated 4997 U/ml/min and made the yeast Kluyveromyces marxianus DIYS11 a promise organism for industrial β-galactosidase production, and the RSM a good tool for the optimization of enzyme production.