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Evolution of Culture Broth Rheological Properties during Propagation of the Entomopathogenic Nematode Steinernema carpocapsae , in Submerged Monoxenic Culture
Author(s) -
ChavarríaHernández Norberto,
Inés RodríguezHernández Adriana,
PérezGuevara Fermín,
Torre Mayra de la
Publication year - 2003
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/bp025569d
Subject(s) - rheology , dilatant , entomopathogenic nematode , shear thinning , nematode , shearing (physics) , shear rate , food science , biology , botany , biological pest control , materials science , composite material , ecology
This article presents the evolution of culture broth rheological properties during monoxenic cultures of Steinernema carpocapsae in cylindrical bottles agitated orbitally. Rheological properties were evaluated in simple‐shear flow conditions and were well‐modeled by the Ostwald‐de Waele model. Rheological properties varied from slightly dilatant, n = 1.2 (–), to moderately pseudoplastic flow behavior, n = 0.6 (–). Nematode concentrations increased from 750 ± 190 to 130 900 ± 6900 nematodes/mL, and the apparent viscosity (η a ) evolved from 4.5 ± 0.7 to 46.6 ± 3.2 mPa·s during the fermentations. Rheological behavior did not appear to be strongly influenced by nematode number and/or its stage of development; however, the release of substances from the decomposition of nematode cadavers appeared to be of great importance. Among the different developmental stages of the nematodes, only juveniles of the first stage (J1) were highly susceptible to the shearing conditions tested (shear stress, θ r θ , from 0.9 to 3.5 Pa during periods of 80–100 min), resulting in the viability loss of 85% of J1 nematodes.