Several methods are available for determining the volumetric oxygen transfer coefficient in bioreactors, though their application in industrial bioprocess has been limited. To be practically useful, mass transfer measurements made in nonfermenting systems must be consistent with observed microbial respiration rates. This report details a procedure for quantifying the relationship between agitation frequency and oxygen transfer rate that was applied in stirred-tank bioreactors used for clinical biologics manufacturing. The intrinsic delay in dissolved oxygen (DO) measurement was evaluated by shifting the bioreactor pressure and fitting a first-order mathematical model to the DO response. The dynamic method was coupled with the DO lag results to determine the oxygen transfer rate in Water for Injection (WFI) and a complete culture medium. A range of agitation frequencies was investigated at a fixed air sparge flow rate, replicating operating conditions used in Pichia pastoris fermentation. Oxygen transfer rates determined by this method were in excellent agreement with off-gas calculations from cultivation of the organism (P = 0.1). Fermentation of Escherichia coli at different operating parameters also produced respiration rates that agreed with the corresponding dynamic method results in WFI (P = 0.02). The consistency of the dynamic method results with the off-gas data suggests that compensation for the delay in DO measurement can be combined with dynamic gassing to provide a practical, viable model of bioreactor oxygen transfer under conditions of microbial fermentation.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/btpr.540 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Floating BiOBr/TiC aerogel spheres for efficient degradation of quinolone antibiotics: Rapid oxygen transfer via triphase interface and effective charges separation by internal electric field.
J Colloid Interface Sci
January 2025
School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China. Electronic address:
The limited transport of oxygen at the solid-liquid interface and the poor charge separation efficiency of single catalyst significantly impedes the generation of reactive oxygen species (ROS), thereby weakening the application potential of photocatalytic technology in water pollution control. Herein, a hollow porous photocatalytic aerogel sphere (calcium alginate/cellulose nanofibers (CA/CNF)) loaded BiOBr/TiC, combining a favourable mass transfer structure with effective catalytic centers was firstly presented. The floatability and hollow pore structure facilitated rapid O transfer via a triphase interface, thereby promoting the generation of ROS.
View Article and Find Full Text PDFExploring the degradation of ofloxacin in sewer overflows by Fe(Ⅵ)/PMS, Fe(Ⅵ)/PDS, and Fe(Ⅵ)/SPC: Overlooked synergistic effect of oxidation and in-situ coagulation.
J Hazard Mater
January 2025
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Ministry of Education Key Laboratory of Yangtze River Water Environment, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
Sewer overflows are a potential source of emerging contaminants to urban waters, posing a threat to ecosystems and human health. Herein, the performance and mechanism of ferrate(Ⅵ) (Fe(Ⅵ))/peroxymonosulfate (PMS), Fe(Ⅵ)/peroxydisulfate (PDS), and Fe(Ⅵ)/percarbonate (SPC) for the degradation of ofloxacin (OFL) in overflows were comparatively investigated. These systems achieved efficient degradation of OFL and the removal of conventional pollutants.
View Article and Find Full Text PDFMassive endobronchial hemorrhage leading to Cardiac arrest during EBUS-TBNA: a case of successful resuscitation.
BMC Pulm Med
January 2025
Department of Pulmonary and Critical Care Medicine, School of Medicine, Zhongshan Hospital of Xiamen University, Xiamen University, Xiamen, Fujian, China.
Introduction: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is commonly used for diagnosing mediastinal lymphadenopathy. Despite a low complication rate, severe hemorrhage can occur which is reported in this literature, particularly in hypervascular conditions like Castleman disease.
Methods: A 54-year-old male with idiopathic multicentric Castleman disease underwent EBUS-TBNA for mediastinal lymph node sampling.
Carboxylated cellulose nanocrystals mediated flower-like zinc oxide for antimicrobial without activation of light.
J Colloid Interface Sci
April 2025
State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China. Electronic address:
Conventional light-driven antimicrobial strategies of zinc oxide (ZnO) are limited by inadequate illumination in dark environments. In this study, carboxylated cellulose nanocrystals (MCNC) mediated flower-like ZnO (C@Z) with self-promoted reactive oxygen species release under dark is fabricated. The adsorption of Zn ions on MCNC prompts the growth of ZnO along the (002) crystal plane, forming a flower-like hybrid with superior dispersibility and oxygen vacancies compared to MCNC-free ZnO, which exposes the (100) plane.
View Article and Find Full Text PDFPoly(3,4-ethylenedioxithiophene) coated on vanadium oxide hydration nanobelts enhancing ammonium-ion storage for hybrid supercapacitors.
J Colloid Interface Sci
January 2025
School of Chemistry, Dalian University of Technology, Dalian 116024 PR China. Electronic address:
The development of electrode materials for aqueous ammonium-ion supercapacitors (NH-SCs) has garnered significant attention in recent years. Poor intrinsic conductivity, sluggish electron transfer and ion diffusion kinetics, as well as structural degradation of vanadium oxides during the electrochemical process, pose significant challenges for their efficient ammonium-ion storage. In this work, to address the above issues, the core-shell VO·nHO@poly(3,4-ethylenedioxithiophene) composite (denoted as VOH@PEDOT) is designed and prepared by a simple agitation method to boost the ammonium-ion storage of VO·nHO (VOH).
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!