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A Quantitative Approach to Characterizing Cell Lysis Caused by Mechanical Agitation of Streptomyces clavuligerus
Author(s) -
Roubos Johannes A.,
Krabben Preben,
Luiten Ruud G. M.,
Verbruggen Henk B.,
Heijnen Joseph. J.
Publication year - 2001
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp0001617
Subject(s) - streptomyces clavuligerus , lysis , yield (engineering) , streptomyces , saturation (graph theory) , biomass (ecology) , strain (injury) , chemistry , chromatography , biological system , biology , biochemistry , bacteria , actinomycetales , materials science , mathematics , ecology , genetics , anatomy , combinatorics , metallurgy
Streptomyces clavuligerus is a commercially important actinomycete that is used to produce clavulanic acid, a β‐lactamase inhibitor. Observations during 10 batch cultivations with S. clavuligerus on defined media have led to the finding that the organism is very sensitive to shear when grown in batch cultures with increasing stirrer speed. The stirrer speed was increased to keep the dissolved oxygen level above 50% air saturation. A quantitative approach based on the calculation of elemental balances and a simple mathematical model is proposed to characterize the biomass lysis. Finally, a linear relation between biomass yield and observed specific growth rate is determined. Results show that cell lysis occurs at a high degradation rate, e.g., μ max = 0.16 h − 1 and k d = 0.07 h − 1 , when the gassed power input increases above 1.1, 1.7, or 2.0 kW/m 3 , respectively, depending on the medium composition. The overall biomass yield on substrate is dramatically reduced in all experiments (>30%).