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Effects of ultrasound on culture of Aspergillus terreus
Author(s) -
Sainz Herrán Nuria,
Casas López José L,
Sánchez Pérez José A,
Chisti Yusuf
Publication year - 2008
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.1821
Subject(s) - sonication , aspergillus terreus , fermentation , biomass (ecology) , lovastatin , food science , ultrasound , rheology , chemistry , biology , microbiology and biotechnology , biochemistry , chromatography , materials science , agronomy , physics , cholesterol , acoustics , composite material
BACKGROUND: Fermentations of Aspergillus terreus are commercially used to produce lovastatin. How ultrasound might influence this fermentation is unknown. While high‐intensity ultrasound is effective in disrupting microbial cells, ultrasound of low intensity is known to improve productivity of some fermentation processes without damaging cells. Mechanisms behind productivity improvements have not been clearly identified in earlier studies. This work reports on the effects of ultrasound on A. terreus fermentation for low (957 W m −3 ), medium (2870 W m −3 ) and high (4783 W m −3 ) values of sonication power input in a slurry bubble column sonobioreactor. RESULTS: Sonication at any power level did not affect biomass growth profiles in comparison with negative controls. In contrast, medium‐ and high‐intensity sonication greatly reduced production of lovastatin and substantially altered the growth morphology. At medium and high intensity, ultrasound disrupted fungal pellets and caused the biomass to grow mainly as dispersed hyphae. Sonication affected broth rheology because rheology depends on the morphology of the suspended biomass. CONCLUSION: Sonication can be used to modify growth morphology and broth rheology without affecting growth of filamentous fungi. Sonication appears to influence the primary growth metabolism and secondary metabolism differently in different situations. Copyright © 2008 Society of Chemical Industry