Department of Applied Biological Chemistry, Utsunomiya University, Tochigi 321-8505, Japan.
Carbohydr Polym. 2013 Jul 1;96(1):314-9. doi: 10.1016/j.carbpol.2013.03.081. Epub 2013 Apr 3.
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.
2,2,6,6-四甲基哌啶-1-氧自由基（TEMPO）介导的氧化作用被应用于支链淀粉，制备水溶性的钠（1→3）-β-多聚半乳糖醛酸，并进一步研究了其生物降解行为。从土壤中分离到一种具有降解（1→3）-β-多聚半乳糖醛酸能力的细菌菌株（EH621），并鉴定为芽孢杆菌属。EH621 菌株在培养（1→3）-β-多聚半乳糖醛酸时，在 3 天内使上清液中的初始总碳减少了约 60%，表明（1→3）-β-多聚半乳糖醛酸可被自然环境中存在的微生物迅速降解和代谢。在 EH621 的无细胞提取物中检测到了水解酶活性，该酶对（1→3）-β-多聚半乳糖醛酸具有高度特异性。对酶解产物的分析表明，（1→3）-β-多聚半乳糖醛酸通过一些低聚物和二聚体，以内切的方式降解为其单体单元，半乳糖醛酸。
