Experimental modeling and optimization of pullulan production by Aureobasidium pullulans AZ-6

• Published in: Polymer bulletin (Berlin, Germany) Vol. 81; no. 10; pp. 9139 - 9180
• Main Authors: Mujdeci, Gamze Nur, Bozdemir, M. Tijen, Ozbas, Z. Yesim
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2024; Springer Nature B.V
• Subjects: Biomass; Carbon; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Experiments; Fermentation; Fourier transforms; Fungi; Infrared analysis; Nitrogen; Optimization; Organic Chemistry; Original Paper; Pathogens; Peptones; Physical Chemistry; Polymer Sciences; Pullulan; Response surface methodology; Soft and Granular Matter; Sucrose; Yeast; Poland; Japan; Turkey; Pullulan; Response surface methodology; Optimization; Central composite rotatable design
• ISSN: 0170-0839; 1436-2449
• DOI: 10.1007/s00289-024-05146-8

The objective of this study was to optimize the fermentation parameters by using response surface methodology for increasing pullulan production of Aureobasidium pullulans AZ-6 in synthetic fermentation medium. The optimum conditions were determined as follows: the initial sucrose concentration ( X 1 ): 100 g/L; the initial peptone concentration ( X 2 ): 11.31 g/L; the initial pH ( X 3 ): 6.48; and the temperature ( X 4 ): 24.2 °C. In the optimum conditions, the maximum exopolysaccharide (EPS) concentration ( Y 1 ), the maximum pullulan concentration ( Y 2 ), the specific growth rate ( Y 3 ), the maximum specific pullulan formation rate ( Y 4 ), and the pullulan yield ( Y 5 ) were expected to be obtained as 37.078 and 35.372 g/L, 0.062 h −1 , 0.021 [g pullulan/(g mo.h)], and 53.681%, respectively. The observed values of Y 1 , Y 2 , Y 3 , Y 4 , and Y 5 were 36.950 g/L, 35.470 g/L, 0.064 h −1 , 0.036 [g pullulan/(g mo.sa)], and 54.480%, respectively, as a result of validation experiments. EPS samples were characterized by Fourier-transform infrared spectroscopy and scanning electron microscope analyses. The optimization process caused more than a 50% increase in EPS and pullulan concentrations. This study showed that the color-variant A. pullulans AZ-6 strain could become a significant industrial strain if it is explored further in the future to produce pullulan on a larger scale.