Project description:Genome mining of pigmented Pseudoalteromonas has revealed a large potential for production of bioactive compounds, both hydrolytic enzymes and secondary metabolites and the purpose of the present study was to explore this bioactivity potential in a potent antibiotic and enzyme producer, Pseudoalteromonas rubra strain S4059. Proteomic analyses indicated that a highly efficient chitin degradation machinery was present in the red-pigmented P. rubra S4059 when grown on chitin. Four GH18 chitinases and two GH20 hexosaminidases were significantly upregulated by chitin. GH19 chitinase which is not common in bacteria is consistently found in pigmented Pseudoalteromonas and in S4059 it was only detected when the bacterium was grown on chitin. To explore the possible role of GH19 in pigmented Pseudoalteromonas, we deleted the GH19 chitinase and compared a range of phenotypes in the mutant and wild type. Neither, the chitin degrading ability or the biofilm forming capacity was affected by GH19 deletion. In some Vibrionaceae, the secondary metabolome is significantly affected by growth on chitin as compared to simpler carbon sources. The secondary metabolites produced by S4059 and the GH19 mutant were xxx start by chitin/mannose – then the mutant. not altered by the absence of the gene, indicating that chitin utilization may not directly influence the production of secondary metabolites as has been observed in some Vibrionaceae. Metabolome analysis reveal that growth on chitin XX. In summary,