Production of β-Glucosidase from a Newly Isolated Aspergillus Species Using Response Surface Methodology

A newly isolated fungus Aspergillus niger SOI017 was shown to be a good producer of β-glucosidase from all isolated fungal strains. Fermentation condition (pH, cellobiose concentration, yeast extract concentration, and ammonium sulfate concentration) was optimized for producing the enzyme in shake flask cultures. Response surface methodology was used to investigate the effects of 4 fermentation parameters (yeast extract concentration, cellobiose concentration, ammonium sulfate concentration, and pH) on β-glucosidase enzyme production. Production of β-glucosidase was most sensitive to the culture medium, especially the nitrogen source yeast extract. The optimized medium for producing maximum β-glucosidase specific activity consisted of 0.275% yeast extract, 1.125% cellobiose, and 2.6% ammonium sulfate at a pH value of 3

Optimization of Pectate Lyase Production from Paenibacillus polymyxa N10 using Response Surface Methodology

The parameters affecting the production of pectate lyase from P. polymyxa N10 were studied using the response surface methodology agitation rate (X1, 100-300 rpm), temperature (X2, 25-45 °C) and pH (X3, 5.5-9.5). The most significant factors influencing enzyme production were temperature and pH. The second order polynomial regression model obtained was fitted and found adequate, with an R2 of 0.9600 (p &lt; 0.001). A maximum pectate lyase activity of 84.5 U/ml was attained in 72 h of cultivation at agitation rate 200 rpm, temperature 35 °C and pH 8. Optimizations of agitation rate and aeration on pectate lyase production were also carried out in a 5-l stirred-tank bioreactor. The aeration rate was varied in the range of 0.5-2 vvm at agitation rate of 200 rpm (temperature 35°C and initial pH 8). At agitation rate of 200 rpm, the shear force was high and then decreased the pectate lyase activity due to its negative effect on the enzyme structure. A maximum pectate lyase activity of 110.42 U/ml in the bioreactor was close to that obtained from the shake flask fermentation study. </jats:p