Identification of Regulatory Genes and Metabolic Processes Important for Alginate Biosynthesis in Azotobacter vinelandii by Screening of a Transposon Insertion Mutant Library

作者: Mali Mærk , Øyvind M. Jakobsen , Håvard Sletta , Geir Klinkenberg , Anne Tøndervik

DOI: 10.3389/FBIOE.2019.00475

关键词:

摘要: Alginates are commercially important polysaccharides with a wide range of industrial and technological applications. Polymer chain length monomer distribution greatly affect the material properties, which makes different alginate types ideal for areas use. All commercial manufacture is currently based on extraction from brown algae, but polymers also produced by bacteria in genera Pseudomonas Azotobacter. Bacterial bioproduction technically possible, not yet economically competitive algal alginates. A. vinelandii an attractive candidate development bacterial strains due to its potential producing homogenous alginates tailored compositions, thus high market value. Successful cultivation conditions however dependent extensive knowledge factors affecting biosynthetic process question.Along availability complete genome sequences, multitude new opportunities has arised regard investigations gene functions, metabolic regulatory relationships, environmental adaptations etc. Part work presented this thesis contribution manual curation annotation first published genome, provided basis our subsequent genomebased analyses production organism. The analysis carried out as part was mainly concerned carbohydrate metabolism genes, foundation further sugar uptake utilization A notable outcome discovery numerous highly similar apparently conserved intra-genome homologs among core genes. Investigations 943 archaeal genomes confirmed that number such indeed unusually large vinelandii. We propose retention multiple copies confers adaptive benefits via dosage and/or increased flexibility.Genes, cellular processes, were investigated construction screening transposon insertion library comprising 4000 mutant strains. Abolished or diminished ~70 mutants disrupted genes identified sequencing. included structural involved biosynthesis, well iron uptake, peptidoglycan recycling, motility synthesis several cofactors central metabolites. Based these results effect various medium supplements wild type investigated, addition thiamine, succinate mixture lysine, methionine diaminopimelate shown result significantly levels. revealed two possible regulators biosynthesis; fructose phosphotransferase system protein FruA IclR family transcriptional regulator. Two have gained increase production. For one mucA, encoding main negative regulator biosynthesis.Global effects inactivating MucA phenotypic characterization transcriptome fermentor-grown mucA lowered growth rate, elevated respiration rate compared strain. Both composition inactivation had profound carbon source utilization. roles key MucA/AlgU control composition, cell mass production, possibly nitrogen fixation. redirection reflected changes gluconeogenesis/glycolysis energy production.The will importance towards long-term goal establishing systems

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