TY - JOUR
T1 - Effects of initial ammonium ion concentration on pullulan production by Aureobasidium pullulans and its modeling
AU - Cheng, Kuan Chen
AU - Demirci, Ali
AU - Catchmark, Jeffrey M.
AU - Puri, Virendra M.
N1 - Funding Information:
This project is funded by Pennsylvania Agricultural Experiment Station . The authors thank the Statistical Consulting Center at Pennsylvania State University for providing guidance on statistical analysis.
PY - 2011/3
Y1 - 2011/3
N2 - Pullulan fermentations by Aureobasidium pullulans with various initial ammonium ion concentrations were evaluated in a 2-L bioreactor. The results demonstrated that A. pullulans produced highest pullulan (23.1 g/L) when the initial ammonium sulfate was 7 at 5 g/L. The purity of produced pullulan was 94.6%. Seven gram per liter of ammonium sulfate produced more biomass due to the higher level of nitrogen source, but the pullulan-degrading enzyme activity was detected after the depletion of sucrose, which reduced pullulan concentration. From the results of fed-batch fermentation, addition of 10 g/L of sucrose suppressed A. pullulans from producing pullulan-degrading enzyme. Additionally, the modified-Gompertz equation demonstrated its generality to fit all pullulan production, biomass production, and sucrose consumption curves at three ammonium sulfate levels. After incorporating the degrading factor, a re-modified-Gompertz equation was obtained that can adequately describe the decrease of pullulan at the late fermentation stage.
AB - Pullulan fermentations by Aureobasidium pullulans with various initial ammonium ion concentrations were evaluated in a 2-L bioreactor. The results demonstrated that A. pullulans produced highest pullulan (23.1 g/L) when the initial ammonium sulfate was 7 at 5 g/L. The purity of produced pullulan was 94.6%. Seven gram per liter of ammonium sulfate produced more biomass due to the higher level of nitrogen source, but the pullulan-degrading enzyme activity was detected after the depletion of sucrose, which reduced pullulan concentration. From the results of fed-batch fermentation, addition of 10 g/L of sucrose suppressed A. pullulans from producing pullulan-degrading enzyme. Additionally, the modified-Gompertz equation demonstrated its generality to fit all pullulan production, biomass production, and sucrose consumption curves at three ammonium sulfate levels. After incorporating the degrading factor, a re-modified-Gompertz equation was obtained that can adequately describe the decrease of pullulan at the late fermentation stage.
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U2 - 10.1016/j.jfoodeng.2010.10.004
DO - 10.1016/j.jfoodeng.2010.10.004
M3 - Article
AN - SCOPUS:78649474518
SN - 0260-8774
VL - 103
SP - 115
EP - 122
JO - Journal of Food Engineering
JF - Journal of Food Engineering
IS - 2
ER -