scholarly journals SCREENING OF FACTORS INFLUENCING EXO-POLYGALACTURONASE PRODUCTION BY ASPERGILLUS NIGER ATCC 120120 USING TWO-LEVEL FRACTIONAL FACTORIAL DESIGN

2019 ◽  
Vol 81 (6) ◽  
Author(s):  
Halifah Pagarra ◽  
Roshanida A. Rahman ◽  
Rachmawaty ◽  
Nor Hasmaliana Abdul Manas

Exo-polygalacturonase was produced by Aspergillus niger ATCC 120120 in a solid-state fermentation using Nephrolepis biserrata leaves. Factors affecting the production of exo-polygalacturonase were determined using a two-level fractional factorial design. The screening process for six factors; pH, incubation time, temperature, pectin concentration, inoculum size and moisture content, that influence the production of exo-polygalacturonase by A. niger was performed. The result of variance analysis (ANOVA) suggested that there were four statistically significant (P < 0.005) factors in the production of exo-polygalacturonase by A. niger. These factors were incubation time, temperature, pectin concentration and moisture content. The statistical analysis shows that the linear mathematical model is significant with coefficient of determination (R2) value of 0.9711. The optimum production of exo-polygalacturonase obtained using the model in this study was at 40.00 U/g.

2018 ◽  
Vol 81 (1) ◽  
Author(s):  
Halifah Pagarra ◽  
Roshanida A. Rahman ◽  
Nur Izyan Wan Azelee ◽  
Rosli Md Illias

Polygalacturonases represent an important member of pectinases group of enzymes with immense industrial applications. The activity of exo-polygalacturonase produced by Aspergillus niger was studied in solid state fermentation (SSF) using Nephrolepis biserrata leaves as substrate. Central composite design (CCD) was used to optimize four significant variables resulted from the screening process that has been initially analyzed for the production of exo-polygalacturonase which are incubation time, temperature, concentration of pectin and moisture content. The optimum exo-polygalacturonase production obtained was 54.64 U/g at 120 hours of incubation time, temperature at 340C, 5.0 g/L of pectin concentration and 75.26% of moisture content. For partial characterization of exo-polygalacturonase, the optimum temperature and pH were obtained at 50°C and pH 4.0, respectively. SDS-PAGE analysis showed that molecular weight of exo-polygalacturonase were 35 and 71 kDa. This study has revealed a significant production of exo-polygalacturonase by A. niger under SSF using cheap and easily available substrate and thus could found immense potential application in industrial sectors and biotechnology


2019 ◽  
Author(s):  
Yasin Orooji ◽  
Fatemeh Noorisafa ◽  
Nahid Imami ◽  
Amir R. Chaharmahali

<p>Using experimental design and statistical analysis (½ Fractional Factorial Design), this study investigates the effect of different parameters in the membrane fabrication on the performance of nanocomposite PES/TiO<sub>2</sub> membrane. </p>


Author(s):  
Joachim S. Graff ◽  
Raphael Schuler ◽  
Xin Song ◽  
Gustavo Castillo-Hernandez ◽  
Gunstein Skomedal ◽  
...  

AbstractThermoelectric modules can be used in waste heat harvesting, sensing, and cooling applications. Here, we report on the fabrication and performance of a four-leg module based on abundant silicide materials. While previously optimized Mg2Si0.3Sn0.675Bi0.025 is used as the n-type leg, we employ a fractional factorial design based on the Taguchi methods mapping out a four-dimensional parameter space among Mnx-εMoεSi1.75−δGeδ higher manganese silicide compositions for the p-type material. The module is assembled using a scalable fabrication process, using a Cu metallization layer and a Pb-based soldering paste. The maximum power output density of 53 μW cm–2 is achieved at a hot-side temperature of 250 °C and a temperature difference of 100 °C. This low thermoelectric output is related to the high contact resistance between the thermoelectric materials and the metallic contacts, underlining the importance of improved metallization schemes for thermoelectric module assembly.


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