Improved <i>β</i>-Carotene and Lycopene Production by <i>Blakeslea trispora</i> with Ultrasonic Treatment in Submerged Fermentation

Institute of Resource Biology and Biotechnology, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China. Fax: 86-27-87 79 22 65. E-mail: mblu@mail.hust.edu.cn

Response surface methodology (RSM) based on Box-Behnken design (BBD) was employed to investigate the effect of ultrasonic treatment on β-carotene production by Blakeslea trispora. The optimized strategy involved exposing three-day-old mycelial cultures to ultrasonic treatment at a fixed frequency of 20 kHz, power of 491 W, treatment time of 3 min, working time of 3 s, and rest time of 5.8 s, repeated four times at a 24-h interval. Mycelium growth was not significantly promoted under ultrasonic stimulation; however, the glucose metabolism increased by about 10 %, the average size of the aggregates significantly decreased, and the uptake rate of imidazole into cells was increased about 2.5-fold. After a 6-d culture, the technique produced 173 mg/L of β-carotene and 82 mg/L of lycopene, which represented an increase of nearly 40.7 % and 52.7 %, respectively, over the yields obtained in cultures without ultrasonic treatment.