Search

An extracellular alkaline protease producing B. amyloliquefaciensSP1 was isolated from apple rhizosphere having multifarious plant growth-promoting activities. B. amyloliquefaciensSP1 protease was immobilized using various concentrations of calcium alginate, agar and polyacrylamide to determine the optimum concentration for formation of the beads. Enzyme activity before immobilization (at 60 °C, pH 8.0 for 5 min) was 3580 µg/ml/min. The results of immobilization with various matrices revealed that 3 % calcium alginate (2829.92 µg/ml/min), 2 % agar (2600 µg/ml/min) and 10 % polyacrylamide (5698.99 µg/ml/min) were optimum concentrations for stable bead formation. Immobilized enzyme reusability results indicated that calcium alginate, agar and polyacrylamide beads retained 25.63, 22.05 and 34.04 % activity in their fifth repeated cycle, respectively. In cell immobilization technique, the free movement of microorganisms is restricted in the process, and a semi-continuous system of fermentation can be used. In the present work, this technique has been used for alkaline protease production using different matrices. Polyacrylamide (10 %) was found with the highest total alkaline protease titer, i.e., 24,847 µg/ml/min semi-continuously for 18 days as compared to agar (total enzyme titer: 5800 in 10 days) and calcium alginate (total enzyme titer: 13,010 in 15 days). This present study reported that polyacrylamide (10 %) among different matrices has maximum potential of immobilization of B. amyloliquefaciensSP1 and its detergent stable alkaline protease with effective application in bloodstain removal.

The effects of yeast extract (X1), NH4NO3(X2), peptone (X3), urea (X4), CMC (X5), Tween 20 (X6), MgSO4(X7), and CaCO3(X8) on production of xylanase from Cellulosimicrobium cellulansCKMX1 were optimized by statistical analysis using response surface methodology (RSM). The RSM was used to optimize xylanase production by implementing the Central composite design. Statistical analysis of the results showed that the linear, interaction and quadric terms of these variables had significant effects. However, only the linear effect of X4, X5, interaction effect of X1X7, X1X8, X2X3, X2X8, X3X6, X3X8, X4X6, X4X7, X5X7, X5X8and quadratic effect of X32, X52and X72found to be insignificant terms in the quadratic model and had no response at significant level. The minimum and maximum xylanase production obtained was 331.50 U/g DBP and 1027.65 U/g DBP, respectively. The highest xylanase activity was obtained from Run No. 30, which consisted of yeast extract (X1), 1.00 g (%); NH4NO3(X2), 0.20 g (%); peptone (X3), 1.00 g (%); urea (X4), 10 mg (%); CMC (X5), 1.00 g (%); Tween 20 (X6), 0.02 mL (%); CaCO3(X7), 0.50 g (%) and MgSO4(X8), 9.0 g (%). The optimization resulted in 3.1-fold increase of xylanase production, compared with the lowest xylanase production of 331.50 U/g DBP after 72 h of incubation in stationary flask experiment. Application of cellulase-free xylanase in pulp biobleaching from C. cellulansCKMX1 under C–EP–D sequence has been shown to bring about a 12.5 % reduction of chlorine, decrease of 0.8 kappa points (40 %), and gain in brightness was 1.42 % ISO points in 0.5 % enzyme treated pulp as compared to control.