Characterisation of mixed microbial populations in white mineral dispersions

• Main Author: Di Maiuta, Nicola
• Published: University of Warwick 2010
• Subjects: 549; QH301 Biology
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526186

In recent years, the microbiology of white mineral dispersions and the application of microbiocides for their preservation have taken a central role for the producer and user with the aim of maintaining high quality requirements such as brightness, rheological parameters, and odour neutrality. Additionally, new applications of mineral dispersions set to open up markets in food, cosmetics and pharmaceutical applications have aroused the interest in the microbiology of white mineral dispersions. Due to the occurrence of biocide resistant bacteria, technical limitations in the usage of biocides, as well as the more rigorous regulatory situation created by the BPD, the demand for new biocide research to ensure continuing effective WMD preservation is increasing. Despite efforts to optimise the application of microbiocides for the storage and protection of mineral dispersions, costs for preservation and disinfection are escalating. These are reasons why the current preservation strategies have been revisited and new preservation strategies have been designed. The work described in this thesis demonstrates that the microbial diversity of white mineral dispersions is greater than previously assumed and gives detailed insight about the microbial diversity of mineral dispersions. The occurrence of microbial contamination in mineral dispersions is of a seasonal nature rather than manufacture site or product type specific. Furthermore, the incidence of biocideresistant bacteria in mineral slurries is increasing and the microbial degradation products of biocidal compounds are disadvantageous for dispersion stability (pH and viscosity). New strategies for the preservation of mineral dispersions have been developed and biocide performance against biocide-resistance bacteria has been enhanced by combining in-use biocides with a range of non-biocidal additives. The industrial application of these new findings contributes to a more efficient preservation of white mineral dispersions with respect to both environmental as well as financial resources and opens up a basis for alternative preservation strategies of white mineral dispersions.