Biodegradation of (1→3)-β-polyglucuronate prepared by TEMPO-mediated oxidation

2,2,6,6-Tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation was applied to curdlan to prepare water-soluble sodium (1→3)-β-polyglucuronate, and its biodegradation behavior was then investigated. A bacterial strain (EH621) having the ability to degrade (1→3)-β-polyglucuronate was isolated from soil, and identified as Paenibacillus sp. Strain EH621 cultured with (1→3)-β-polyglucuronate decreased the initial total carbon in the supernatant by approximately 60% within 3 days, showing that (1→3)-β-polyglucuronate can be readily degraded and metabolized by microorganisms present in the natural environment. Hydrolytic enzyme activity was detected in the cell-free extract of EH621, which was highly specific to (1→3)-β-polyglucuronate. Analyses of the enzymatic degradation products revealed that (1→3)-β-polyglucuronate was endolytically degraded to its monomeric unit, glucuronate, via some oligomers and dimers.