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6‐pentyl‐α‐pyrone production by Trichoderma harzianum : The influence of energy dissipation rate and its implications on fungal physiology
Author(s) -
RochaValadez J. Antonio,
Hassan Mainul,
Corkidi Gabriel,
Flores Celia,
Galindo Enrique,
SerranoCarreón Leobardo
Publication year - 2005
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.20489
Subject(s) - trichoderma harzianum , bioreactor , growth rate , biology , fermentation , metabolism , energy metabolism , food science , spore , botany , chemistry , biophysics , zoology , biochemistry , biological pest control , geometry , mathematics , endocrinology
The influence of the agitation conditions on biomass growth, morphology, carbon metabolism, viability, and 6‐pentyl‐α‐pyrone (6PP) production by Trichoderma harzianum were studied in an extractive fermentation system. Batch spore‐inoculated cultures developed at dissolved oxygen concentrations above 35% of air saturation were carried out in a 14 L bioreactor. The effect of energy dissipation rate over culture performance was assessed using two sets of three Rushton turbines (having different diameters) operated at different agitation speeds. Higher mechanical stress enhanced cellular differentiation (i.e., sporulation), while yielding lower specific growth rates and increased specific CO 2 production rates (CPRs) at relatively constant specific glucose consumption rates. In addition, fungal viability and clump mean diameter decreased gradually at higher energy dissipation rates. 6PP biosynthesis was growth associated and its specific productivity showed a bell‐shaped relationship with the energy dissipation rate. T. harzianum physiology was, therefore, strongly influenced by the prevailing hydrodynamic conditions as it triggered cellular metabolism and differentiation shifts. © 2005 Wiley Periodicals, Inc.