Karl Stone

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A Method of using off-line Measurements in an On-line Estimator of Biomass Concentration for a Penicillin Fermentation, and its Effects on the Quality of the Estimates

IFAC Proceedings Volumes, Mar 1, 1992

Abstract A method of improving on-line estimation of the biomass concentration for a fed-batch pe... more Abstract A method of improving on-line estimation of the biomass concentration for a fed-batch penicillin fermentation, by using the information available in off-line measurements of biomass concentration, is presented. The on-line estimator was based on a well known, two parameter model that relates respiratory activity, in the form of carbon dioxide evolution rate measurements, to growth and non growth associated culture activities. The off-line measurements were used to identify one of the model parameters. In an illustrative example, estimation is shown to be improved using off-line measurements that are delayed by up to 24.5 hours. The quality of the estimation was found to decrease with increasing analysis delay.

Comprehensive identification of essential Staphylococcus aureus genes using Transposon-Mediated Differential Hybridisation (TMDH)

BMC Genomics, 2009

Background In recent years there has been an increasing problem with Staphylococcus aureus strain... more Background In recent years there has been an increasing problem with Staphylococcus aureus strains that are resistant to treatment with existing antibiotics. An important starting point for the development of new antimicrobial drugs is the identification of "essential" genes that are important for bacterial survival and growth. Results We have developed a robust microarray and PCR-based method, Transposon-Mediated Differential Hybridisation (TMDH), that uses novel bioinformatics to identify transposon inserts in genome-wide libraries. Following a microarray-based screen, genes lacking transposon inserts are re-tested using a PCR and sequencing-based approach. We carried out a TMDH analysis of the S. aureus genome using a large random mariner transposon library of around a million mutants, and identified a total of 351 S. aureus genes important for survival and growth in culture. A comparison with the essential gene list experimentally derived for Bacillus subtilis highligh...

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Dry weight measurement of microbial biomass and measurement variability analysis

Biotechnology Techniques, 1992

Comprehensive identification of essential Staphylococcus aureus genes using Transposon-Mediated Differential Hybridisation (TMDH)

BMC Genomics, Jul 1, 2009

Background: In recent years there has been an increasing problem with Staphylococcus aureus strai... more Background: In recent years there has been an increasing problem with Staphylococcus aureus strains that are resistant to treatment with existing antibiotics. An important starting point for the development of new antimicrobial drugs is the identification of "essential" genes that are important for bacterial survival and growth. We have developed a robust microarray and PCR-based method, Transposon-Mediated Differential Hybridisation (TMDH), that uses novel bioinformatics to identify transposon inserts in genome-wide libraries. Following a microarray-based screen, genes lacking transposon inserts are re-tested using a PCR and sequencingbased approach. We carried out a TMDH analysis of the S. aureus genome using a large random mariner transposon library of around a million mutants, and identified a total of 351 S. aureus genes important for survival and growth in culture. A comparison with the essential gene list experimentally derived for Bacillus subtilis highlighted interesting differences in both pathways and individual genes. We have determined the first comprehensive list of S. aureus essential genes. This should act as a useful starting point for the identification of potential targets for novel antimicrobial compounds. The TMDH methodology we have developed is generic and could be applied to identify essential genes in other bacterial pathogens.

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Fault Detection and Identification in Fermenters

IFAC Proceedings Volumes, Mar 1, 1992

This paper outlines a method for detection and analysis of abnormal fermenter operation for small... more This paper outlines a method for detection and analysis of abnormal fermenter operation for small scale fermenters, such as those typically used for strain development work. The work was based on the desire to further improve the operability of fermenters used in the strain improvement effort of the project's sponsors. The work was based on fed . batch penicillin fermentations, performed by the method described by . The method is illustrated by a case study from a specific fed batch penicillin fermentation.

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Two methods of selecting smoothing splines applied to fermentation process data

Aiche Journal, Apr 1, 1994

splines with a low percentage fit extracted trends from the data, while for general use a 50% fit... more splines with a low percentage fit extracted trends from the data, while for general use a 50% fit appeared satisfactory. The goodness-of-fit method executed more quickly than the GCV/GA method, but the GCV/GA method was more generally applicable as it chose both the degree of the spline and the amount of smoothing automatically.

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The use of off-line measurement information in the on-line state estimation of fed-batch penicillin fermentations

Thesis (Ph. D.)--University of London, 1995.

format_quoteThe EKF estimator was unstable despite accurate estimation; performance worsened under practical measurement conditions.format_quote

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