Effect of two-stage controlled pH and temperature on pullulan production by Auerobasidium pullulans

Effect of two-stage controlled pH and temperature on cell growth and pullulan production by Auerobasidium pullulans was investigated. Lower pH and higher temperature supported cell growth of A. pullulans, while higher pH and lower temperature stimulate pullulan synthesis. Maximum pullulan production (39 g/L) was obtained at initially lower pH (2.5) and higher temperature (32 degrees C), subsequently higher pH (5.5) and lower temperature (26 degrees C), and higher than those achieved at uncontrolled pH (initial pH 5.5) with two-stage temperature (initially 32 degrees C and subsequently 26 degrees C), or two-stage pH (initially pH 2.6 and subsequently 5.5) with constant temperature 26 degrees C. Results indicate that combination of two-stage controlled pH and temperature support mass production of pullulan. (C) 2011 Elsevier Ltd. All rights reserved.