Department of Genetics

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https://scholar.sun.ac.za/handle/10019.1/21

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Browsing Department of Genetics by browse.metadata.advisor "Bekker, J."

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    Isolation and characterisation of genes encoding biopolymer manufacturing enzymes
    (Stellenbosch : Stellenbosch University, 2012-03) Rapp, Telana; Bekker, J.; Kossmann, J. M.; Stellenbosch University. Faculty of AgriSciences. Dept. of Genetics. Institute for Plant Biotechnology.
    ENGLISH ABSTRACT: Biopolymers exhibit the required material properties to replace conventional, non-biodegradable, petroleum-based polymer products. They have a closed carbon cycle, making them carbon neutral and environmentally friendly. Biopolymers are produced from non-toxic substrates during in vivo enzymatic reactions. Biosynthesis of the most commercially important biopolymers is too complex to be reproduced in in vitro reactions. Identification of the genes responsible for their biosynthesis has been under investigation, with some pathways already elucidated. The genes involved in the biosynthesis of these polymers have been targeted for genetic manipulation to increase productivity, as well as create tailor-made polymers. Novel biopolymers and the genes responsible for their synthesis are of interest for their potential commercial applications. Bacteria produce a wide range of biopolymers and are being implemented as the bio-factories for biopolymer production. They are capable of utilising easily accessible and renewable carbon sources such as sucrose for polymer biosynthesis. Bacteria thus allow for economical production of these environmentally beneficial polymers. In this study, the gene responsible for the production of an unknown biopolymer from an unknown bacterium was identified. The biopolymer producing bacteria were grown on media enriched with sucrose as carbon source, during an expression library screening in a previous study. Expression library technology was used to search for the gene and it was identified as a 424 amino acid levansucrase which had a 100% homology to Leuconostoc mesenteroides M1FT levansucrase (AAT81165.1). Biopolymer analysis revealed that the biopolymer was a levan, a polysaccharide consisting of only fructose molecules with a molecular weight of ± 5 kDa. Analysis of a 516 bp fragment of the 16S rRNA determined that the unknown bacteria were a Pseudomonas species.