Molecular Characterization And Enzymatic Properties Of Agarase Production By The Algal Degrading Bacterium Alteromonas Sp. Aga1552

The present study reports the isolation of a highly active agar-degrading bacterium,Aga1552,from Indonesian macroalgae and its identification as Alteromonas sp.The whole genome sequencing of Aga1552 revealed the annotation of 145 polysaccharide-degrading enzyme genes,including 16 genes related to agar degradation.Among these genes,three agarase sequences(aga1364,aga1365,and aga2457)from different agarase families were selected for bioinformatics analysis,gene cloning,and recombinant expression in Escherichia coli.The purified recombinant agarases showed optimal enzymatic activity at 50°C and pH 7.0(Tris-HCl buffer)with high thermal stability,providing a basis for their potential industrial application.Enzymatic product analysis demonstrated that Aga1364 mainly produced neoagarose,while Aga1365 produced neoagarobiose(NA2),neoagarotetraose(NA4),and neoagarhexose(NA6).Aga2457 showed the ability to degrade neoagarobiose to produce galactose and 3,6-anhydro-galactose(AHG).Synergistic degradation was observed when the three recombinant agarases were used in combination.The findings of this study provide a scientific basis and technical support for the enzymatic preparation of algal oligosaccharides,particularly3,6-anhydro-galactose,from marine macroalgae polysaccharides.