Application of Doehlert experimental design in the optimization of experimental variables for the Pseudozyma sp. (CCMB 306) and Pseudozyma sp. (CCMB 300) cell lysis Aplicação do modelo Doehlert na otimização das variáveis experimentais para a lise de Pseudozyma sp. (CCMB 306) e Pseudozyma sp. (CCMB 300)Amanda Reges de SENA 1,3 , Gildomar Lima VALASQUES JÚNIOR 1,2 , Ingara Keisle São Paulo BARRETTO 1 , Sandra Aparecida ASSIS 1 * IntroductionThe cell wall of yeast is basically made of glucan and mannan-protein. Lytic enzymes such as chitinases, proteases and β-1,3-glucanases are usually necessary. There are numerous applications for biotechnologies: preparation of protoplasts, extraction of pigments, mass treatment of residual yeast cell fermentation industries for preparation of animal feed, in studies of the mechanism of cell wall synthesis for control of pathogenic yeast, etc. (HUNTER;ASENJO, 1988;SATO, 2005;SALAZAR; ASENJO, 2007).These enzymes are capable of lysing the cell wall of Saccharomyces cereviseae, Candida sp. and other genera of yeasts, which extends their use allowing the selective manufacture of products, regardless of scale, and can be performed under temperature and pH conditions that do not involve the denaturation of cellular products of interest (FLEURI; SATO, 2005). Mathematical models have been increasingly used to help explain responses of biochemical reactions. This technique is often used for optimization and/or verification of the influence of medium components and cultivation parameters for enzyme production (FLEURI; SATO, 2008).The production and optimization of the parameters that affect the enzymatic synthesis should always be investigated because the optimal conditions vary among different organisms and different enzymes (BRAVO et al., 2000). In many cases, the interaction of parameters that influence fermentation processes can be evaluated with a reduced number of tests using an experimental design (THÉODORE; PANDA, 1995). Several experimental design models could be used to reduce the number of experiments under different conditions. Among them are the Plackett-Burman, Doehlert, Central Composite, and Box-Behnken (LI et al., 2007).The choice of Doehlert design is justified by a number of advantages such as (1) its spherical experimental domain with an uniformity in space filling, (2) its ability to explore the whole of the domain, and (3) its potential for sequentially where the experiments can be reused when the boundaries have not been well chosen at first (BENSALAH et al., 2010). Doehlert designs are easily applied to optimized variables and offer advantages over the Central Composite (CCD) and Box-Behnken designs, used in response surface analysis. They need fewer experiments, ResumoO presente trabalho visou verificar a influência do pH e temperatura na lise de leveduras utilizando planejamento experimental. No estudo, foi utilizado o extrato enzimático, contendo β-1,3-glucanase e quitinase líticas, obtidas do micro-organismo Moniliophthora perniciosa. O delineamento experiment...