Polyphasic study, species description and significance of novel chryseobacterium species isolated from poultry sources

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dc.contributor.advisorHugo, C. J.
dc.contributor.advisorCharimba, G.
dc.contributor.advisorNewman, J. D.
dc.contributor.advisorHitzeroth, A.
dc.contributor.advisorSteyn, L.
dc.contributor.authorNde, Adeline Lum
dc.date.accessioned2020-12-15T05:40:42Z
dc.date.available2020-12-15T05:40:42Z
dc.date.issued2020-01
dc.description.abstractChryseobacterial strains have been isolated from sources like soil, beer bottles, plants and hospital equipment. Other sources include poultry, meat, fish, milk, creamed rice and canned vegetables where they have been reported to cause food spoilage. They have a wide range of applications ranging from the production of keratinases for the degradation of chicken feather keratin, to the degradation of toxic environmental compounds like flubendiamide. They have also been reported to offer protection to plants where some protect plants against pathogens and possess plant growth-stimulating properties. In the first section of this study, a polyphasic approach was used to describe two novel strains of Chryseobacterium (1_F178T and 5_R23647). 16S rRNA sequencing was done and phylogenetic analysis confirmed Chryseobacterium jejuense and Chryseobacterium nakagawai as the closest relatives of strain 1_F178T, and Chryseobacterium piscium and Chryseobacterium balustinum as the closest relatives of strain 5_R23647. Phenotypic, chemotaxonomic and genotypic methods confirmed the affiliation of both strains to the genus Chryseobacterium, and only confirmed strain 1_F178T as a novel species of Chryseobacterium, to which the name Chryseobacterium pennae was proposed. The growth kinetics of Chryseobacterium strain 1_F178T, 5_R23647, Chryseobacterium carnipullorum and the spoilage specific microorganism, Pseudomonas fluorescens were investigated in the second section of this study, to determine their spoilage potential. Chryseobacterium strain 1_F178T had the highest specific growth rate which indicated a higher spoilage potential. Its growth at temperatures as low as 4 °C was indicative of growth at refrigeration with possibly food spoilage. Chryseobacterium carnipullorum had the highest activation energy implying it has a high sensitivity to change in temperature. The lowest activation energy was obtained for P. fluorescens indicative of this microorganism being less sensitive to changes in temperature, hence can grow over wider temperature ranges, and will therefore have a higher spoilage potential than the chryseobacterial strains in this study and as confirmed in literature. The Huang model was seen as a more effective model in predicting the minimum and maximum temperatures for growth. Analysis using the BiologTM Phenotype MicroArray (PM) system showed the ability of Chryseobacterium strain 1_F178T to oxidise a wide range of substrates ranging from fatty acids, carbohydrates, carboxylic acids, amino acids and polymers, which is linked to its spoilage potential. Strain 1_F178T was able to oxidise a number of fungicides which showed potential of this organism for agricultural applications.en_ZA
dc.identifier.urihttp://hdl.handle.net/11660/10892
dc.language.isoenen_ZA
dc.publisherUniversity of the Free Stateen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA
dc.subjectThesis (Ph.D. (Microbial, Biochemical and Food Biotechnology))--University of the Free State, 2020en_ZA
dc.subjectChryseobacteriumen_ZA
dc.subjectFood spoilageen_ZA
dc.subjectStrain 1_f178ten_ZA
dc.subjectStrain 5_r23647en_ZA
dc.subjectPolyphasic approachen_ZA
dc.subjectTaxonomyen_ZA
dc.subjectWhole genome sequencingen_ZA
dc.subjectGrowth kineticsen_ZA
dc.subjectPhenotype microarrayen_ZA
dc.subjectApplicationen_ZA
dc.subjectPredictive microbiologyen_ZA
dc.titlePolyphasic study, species description and significance of novel chryseobacterium species isolated from poultry sourcesen_ZA
dc.typeThesisen_ZA
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