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Free radical aspects of Xanthomonas campestris cultivation with liquid phase oxygen supply strategy

DSpace at IIT Bombay

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Title Free radical aspects of Xanthomonas campestris cultivation with liquid phase oxygen supply strategy
 
Creator RAO, YMANJULA
SURESH, AK
SURAISHKUMAR, GK
 
Subject ros level
xanthomonas campestris
antioxidants
xanthan gum
 
Description Reactive oxygen (free radical) species such as hydroxyl, superoxide or peroxyl radicals significantly affect cell function and, therefore, determine bioreactor productivities. The specific intracellular reactive oxygen species (ROS) levels as well as the ROS type, during the log and stationary phases of several Xanthomonas campestris (both untreated and HOCl-treated cells) cultivations in the bioreactor, with and without antioxidants, were measured through electron spin resonance (ESR) spectroscopy. Depending on the cultivation conditions, intracellular hydroxyl or superoxide radicals at different levels were detected. The oxygen supply during the cultivations was through need-based, pulse additions of hydrogen peroxide (H2O2), which was subsequently decomposed by culture catalase to yield oxygen. Using data from all cultivations, it was found that the growth rate constant decreased with the log-phase intracellular ROS level; the specific productivity of xanthan gum was found to be optimal at an intracellular ROS level of 0.33 mmol per g cell in the stationary phase. The rheology of the xanthan gum produced in various cultivations is discussed. Further, a model, which can simulate and predict the specific total intracellular ROS level in the cultivations with untreated cells have been developed.
 
Publisher Elsevier
 
Date 2009-03-09T07:48:22Z
2011-11-25T18:58:43Z
2011-12-26T13:07:28Z
2011-12-27T05:55:31Z
2009-03-09T07:48:22Z
2011-11-25T18:58:43Z
2011-12-26T13:07:28Z
2011-12-27T05:55:31Z
2003
 
Type Article
 
Identifier Process Biochemistry 38(9), 1301-1310
1359-5113
http://dx.doi.org/10.1016/S0032-9592(02)00328-X
http://hdl.handle.net/10054/920
http://dspace.library.iitb.ac.in/xmlui/handle/10054/920
 
Language en