UTILISATION DE LA PLANIFICATION EXPERIMENTALE POUR L’OPTIMISATION DE LA PRODUCTION DE L’ α - AMYLASE PAR RHIZOPUS ORYZAE.

The production optimization of α-amylase (E.C.3.2.1.1.) from Rhizopus oryzae fungus is obtained with statistical experimental design. The methodology was based on the Plackett and Burman design (N = 12) [12 experiments and 11 factors in which 8 are real ones (agitation, pH, starch, yeast extract, ‘‘corn steep liquor’’, NaNO3 , salts and Tween 80) and 3 errors. This design has been chosen in order to select the factors favoring enzyme production and biomass. The production medium is prepared using cheese whey. The observed results are adjusted using a multiple linear regression. Indeed, the most influential factors on biomass include agitation, starch, yeastextract, the "corn steep liquor" and salts. All these factors increase positively the biomass: a significant way for agitation (p=0.270), (p=0.133) for yeast extract and (p=0.194) for the "corn steep liquor and salts (p=0.095) and highly significant for starch (p=0.039). In terms of production of α-amylase, it is positively correlated with starch (p=0.145) and yeast extract (p=0.156) but variation of agitation from 100 to 200 rpm and the addition of NaNO3 to 36 g/l appear to be negatively correlated with the production of the enzyme