EFFECT OF FORCED INTERNAL AIR CONVECTION IN PHYTASE ACTIVITY PRODUCED BY Aspergillus niger IN SOLID-STATE FERMENTATION ON TRAY BIOREACTOR (original) (raw)
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Improvement of heat removal in solid-state fermentation tray bioreactors by forced air convection
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Bioresources and Bioprocessing
Background The growth of Aspergillus awamori and Aspergillus oryzae in a self-designed, multi-stacked circular tray solid-state bioreactor (SSB), operating in solid-state fermentation (SSF) conditions at a laboratory scale, was studied. The bioreactor was divided into six layers by six circular perforated trays. Wheat bran was used as both a carrier of bound mycelia and nutrient medium for the growth of A. awamori and A. oryzae. The new tray SSB is equipped with instrumentation (an oxygen (O2)/carbon dioxide (CO2) gas analyser and a thermocouple) to continuously monitor O2 consumption and CO2 and heat evolved, which can directly be used to monitor the fungal biomass. The integrated Gompertz model was used to describe the accumulated evolution of CO2. Results The results from the models strongly suggest that the evolved and accumulated CO2 can be used to excellently describe fungal growth. Another important parameter that can be determined by the gas balance method is the respiratory...
Research, Society and Development
The production of phytase and biomass (estimated by the ergosterol content) by submerged fermentation with Aspergillus niger var. phoenicis URM 4924 was studied. Experimental assays were carried under different conditions of pH (4.0 to 8.0) and temperature (25 to 35 ºC), and the influence of these variables on the responses was studied through a 22 central composite design and response surface methodology. Phytase and biomass production were strongly affected by the pH and temperature used during fermentation. Phytase activity was increased in up to 7.8-fold (from 1.04 to 8.09 U/mL) and the ergosterol content was increased in up to 38-fold (from 9.3 to 354.09 µg/mL). The maximum values of both responses were achieved when using pH 4.0 and 30 ºC. Good correlation (second-order fit, R2 = 0.9875) was found between the data obtained for phytase activity and ergosterol content, suggesting that the phytase production depends on the biomass formation. These results are of interest since th...
Firstly, improvement of culture condition on phytase production by Aspergillus ficuum was investigated using submerged fermentation. The four factors studied were significantly effective on the phytase production. The optimum values for the factors were determined via response surface methodology (RSM) as: glucose, 5.23 g/100 mL; ammonium sulphate, 1.6 g/100 mL; wheat bran, 3.28 g/100 mL, and fermentation time, 198.30 h. The produced amount of phytase under these conditions was 40.21 U/ mL. In the next stage, the process was scaled up to a 3-L batch bioreactor. The highest level of phytase produced in this stage was 85.41 U/mL, which resulted in a 2.1-fold enhancement. In the last stage, the results of optimization of phytase production in solid-state fermentation were further scaled up to packed bed solid-state bioreactor. The highest level of phytase produced in this stage was 87.75 U/gds, which resulted in a 3.4-fold enhancement.