Multivariable parameter optimization for the endoglucanase production by Trichoderma reesei Rut C30 from Ocimum gratissimum seed

Abstract

ABSTRACT The aim of this study was to evaluate the interaction effects of the physico-chemical parameters on the endoglucanase (CMCase) production by Trichoderma reesei Rut C30 on a cellulosic agro-residue by the solid-state fermentation (SSF) and to determine their optimum values by the EVOP factorial design technique. The best combination of physical parameters for the maximum production of the endoglucanase (CMCase) was 28 o C temperature, 79% relative humidity and 4.8 pH of the medium. The best combination of the chemical parameters was (mg/L) nicotinic acid 15, naphthalene acetic acid 7, ferric chloride 5 and Tween-80 6. With the application of this technique, the yield of the CMCase increased by ~ 2.3 fold. Key words: Enzyme, endoglucanase, carboxymethylcellulase (CMCase), EVOP factorial design technique * Author for correspondence INTRODUCTION Cellulases have attracted much interest because of the diversity of their application. Since the cost of production is the major constraint in the cellulase production, much attention is drawn on the availability of low cost carbon source and on effective fermentation system. Fungal cellulases are produced in large amounts, which include all the components of multi enzyme system acting in a synergism for the complete hydrolysis of the cellulose. Trichoderma reesei Rut C30 is known to be one of the best cellulolytic fungal strain, which makes it an ideal test organism for the cellulase production. The organism produces CMCase in major level than the other two enzymes, exo-β-glucanase and β-glucosidase (Chahal et al ., 1982; Juhasz et al ., 2004). Both the liquid and solid -state fermentations have been tried for the cellulase production by Trichoderma sp . (Esterbauer et al ., 1991; Kubicek, 1992; Montenecourt, 1983). Wheat bran has been extensively used in SSF (Jabbar and Ilahi, 1981). Reports on the production of the cellulase by Trichoderma sp. in SSF (Chahal, 1985; Chahal, 1986; Chahal, 1991; Kim et al ., 1985; Sim et al ., 1990) are numerous because different strains and mutants, culture conditions and substrates have been used under different studies. In the present study, the fungus was grown on a novel substrate (mixture of sawdust and seeds of Ocimum gratissimum, ) and through optimization of the physicochemical parameters of the solid-state fermentation process, enhanced yield of CMCase was expected.