Ultrasound-intensified laccase production from Trametes versicolor.
An efficient intermittent ultrasonic treatment strategy was developed to improve laccase production from Trametes versicolor mycelia cultures. The optimized strategy consisted of exposing 2-day-old mycelia cultures to 5-min ultrasonic treatments for two times with a 12-h interval at the fixed ultrasonic power and frequency (120 W, 40 kHz). After 5 days of culture, this strategy produced the highest extracellular laccase activity of 588.9 U/L among all treatments tested which was 1.8-fold greater than the control without ultrasound treatment. The ultrasonic treatment resulted in a higher pellet porosity that facilitated the mass transfer of nutrients and metabolites from the pellets to the surrounding liquid. Furthermore, the ultrasonic treatment induced the expression of the laccase gene (lcc), which correlated with a sharp increase in both extracellular and intracellular laccase activity. This is the first study to find positive effects of ultrasound on gene expression in fungal cells. These results provide a basis for understanding the stimulation of metabolite production and process intensification by ultrasonic treatment in filamentous fungal culture.
National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
Feng
F
Wang
An-Zhou
AZ
Ma
Chen
C
Guo
Guo-Qiang
GQ
Zhuang
Chun-Zhao
CZ
Liu
D046508:Culture Techniques / Q000379:methods*; D005110:Extracellular Space / Q000201:enzymology; D007101:Immersion; D042541:Intracellular Space / Q000201:enzymology; D042845:Laccase / Q000096:biosynthesis* / Q000235:genetics; D025282:Mycelium / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D055454:Trametes / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D014465:Ultrasonics
D042845:Laccase