Application of response surface methodology to evaluate the influence of temperature and initial pH on the production of β-1,3-glucanase and carboxymethylcellulase from Trichoderma harzianum

Abstract: This listing covers the period May 1, 1997 through to June 30, 1997. Citations are arranged in groups which roughly correspond with the British Mycological Society's Special Interest Committees. All correspondence about this item should be addressed to the Executive Editor. Reprints of this feature will not be available.

Abstract: Response surface methodology was employed to study the effect of liquid:solid ratio, NaCl concentration and reaction time on the production of protein from germinant pumpkin seeds. Regression analysis was performed on the data obtained. The most relevant variable was liquid:solid ratio. The coefficient determination ( R 2 ) was good for the second-order model. A liquid:solid ratio of 30.2: 1 (v/w), a NaCl concentration of 4.26% and a reaction time of 18.1 min were found to be optimal for protein extraction from germinant pumpkin seeds. By means of additional experiments, the adequacy of this model is confirmed.

Abstract: The effects of cultivation medium compositions including tapioca, fishmeal, CaCO3 and (NH4)2SO4 for the growth of Bacillus thuringiensis YMB 96-1988 were accessed by using response surface methodology (RSM). The two-level (24–1) fractional factorial designs (FFD) which involve two concentrations of each nutrient, and the paths of steepest ascent were effective in searching for the major factors of the bacteria growth. This allows the fitting of a first order linear model to the data. In this study, supplementary CaCO3 showed a negative effect on the spore production based on the first order regression coefficients derived from SAS programme. Subsequently, a 23 central composite design (CCD) was used for allocation of treatment combinations. Preliminary studies showed that tapioca and fishmeal is believed to be the major factors for the growth of B. thuringiensis. Estimated optimum compositions for the production of spores by B. thuringiensis are as follows: tapioca, 5.01%; fishmeal 5.86%; (NH4)2SO4 0.06% and resulted in a maximum spore count of 8.56 × 108/ml was obtained. This value is close to the 8.35 × 108/ml spore density as counted from actual experimental observations.

Abstract: The effect of temperature (25–80°C), water to seed ratio (25:1–85:1) and pH (3–9) on the yield, apparent viscosity and emulsion stability index of wild sage seed hydrocolloid was investigated. The generated quadratic model showed that the optimum conditions for maximizing the responses were when temperature was 25°C, water to seed ratio was 51:1 and pH was 5.5. All hydrocolloid solutions (1% w/v) showed shear thinning behavior in different extraction conditions, consistency coefficient and flow behavior index varied from 4.455 to 9.435 (Pa.sn), and 0.317 to 0.374, respectively. Besides, the chemical compositions of the seed and extracted gum were determined at optimal conditions.

Abstract: The reaction conditions were optimized for enzymatic hydrolysis of pectic substances using pectolytic enzymes produced by Aspergillus niger NCIM 548. Response surface methodology was used to optimize the reaction parameters and the central composite design was employed for this purpose. Pectin was used as the substrate for polymethylgalacturonase and pectinlyase, whereas polygalacturonic acid was the substrate for polygalacturonase. The volume ratio of reactants for maximum hydrolysis was determined under the assay conditions. The optimum amount of substrate and enzyme were found to be 0.2 cm 3 and 0.074 cm 3 for polymethylgalacturonase, 0.4 cm 3 and 0.086 cm 3 for polygalacturonase, and 0.63 cm 3 and 0.7 cm 3 for pectinlyase. The pH and temperature optima were found to be 5.3 and 30°C for polymethylgalacturonase, 6.6 and 26°C for polygalacturonase, and 4.8 and 35°C for pectinlyase. Under optimized conditions the enzyme activities were higher when compared to unoptimized conditions.

Abstract: Advances in Enzymology and Related Subjects of Biochemistry Vol 24 Edited by F F Nord Pp v + 572 (New York and London: Interscience Publishers, a Division of John Wiley and Sons, 1962) 120s

Abstract: When grown in dual culture, hyphae of the majority of Trichoderma isolates coiled around hyphae of different test fungi. Penetration of hyphae by Trichoderma hyphae seldom occurred. The importance of antibiotics and extracellular enzymes during hyphal interaction is discussed.

Abstract: A filter paper assay method and unit value is described for the measurement of enzyme saccharification action. The method is simple, reproducible, and quantitative and predicts enzyme action under practical saccharification conditions. (JSR)