초록
<P><B>Abstract</B></P><P>To improve biomass production and glucoamylase activity (GA) by <I>Candida famata</I>, culture conditions were optimized. A 2<SUP>3</SUP> full factorial design (FFD) with a response surface model was used to evaluate the effects and interactions of pH (<I>X</I><SUB>1</SUB>), time of cultivation (<I>X</I><SUB>2</SUB>), and starch concentration (<I>X</I><SUB>3</SUB>) on the biomass production and enzyme activity. A total of 16 experiments were conducted toward the construction of an empiric model and a first‐order equation. It was found that all factors (<I>X</I><SUB>1</SUB>, <I>X</I><SUB>2</SUB>, and <I>X</I><SUB>3</SUB>) and their interactions were significant at a certain confidence level (<I>P</I> < 0.05). Using this methodology, the optimum values of the three tested parameters were obtained as follows: pH 6; time of cultivation 24 H and starch concentration 7 g/L, respectively. Our results showed that the starch concentration (X3) has significantly influenced both dependent variables, biomass production and GA of <I>C. famata</I>. Under this optimized medium, the experimental biomass production and GA obtained were 1.8 ± 0.54 g/L and 0.078 ± 0.012 µmol/L/Min, about 1.5‐ and 1.8‐fold, respectively, higher than those in basal medium. The (<I>R</I><SUP>2</SUP>) coefficients obtained were 0.997 and 0.990, indicating an adequate degree of reliability in the model. Approximately 99% of validity of the predicted value was achieved.</P>