1H NMR imaging study of enzymatic degradation in poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Evidence for preferential degradation of the amorphous phase by PHB depolymerase B from Pseudomonas lemoignei
1H NMR imaging study of enzymatic degradation in poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Evidence for preferential degradation of the amorphous phase by PHB depolymerase B from Pseudomonas lemoignei
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DOI：
10.1021/ma971193m
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发表时间：
1997-12
期刊：
影响因子：
5.5
通讯作者：
A. Spyros;R. Kimmich;B. Briese;D. Jendrossek
中科院分区：
文献类型：
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作者：
A. Spyros;R. Kimmich;B. Briese;D. Jendrossek
1 H NMR 成像已用于监测来自柠檬假单胞菌的 PHB 解聚酶 B 对聚（3-羟基丁酸酯）、PHB 和聚（3-羟基丁酸酯-co-23%-3-羟基戊酸酯）、PHB/V 的酶促降解。所检查的样品是通过熔铸生产的厚度约为200μm的薄膜。由于只有半结晶薄膜的非晶区域对 1H NMR 图像强度有贡献，因此当与总重量损失测量相结合时，该技术提供了有关薄膜非晶区域降解过程的独特信息。研究发现，虽然 PHB 和 PHB/V 薄膜的总重量损失率是恒定的，但正如之前报道的那样，初始非晶材料消耗率是指数级的。在降解过程的初始阶段，长达 40−60 小时，发现解聚酶 B 会优先消耗无定形材料。在后期阶段，对非晶态材料的偏好减弱，晶体和非晶态材料都...
1H NMR imaging has been used to monitor the enzymatic degradation of poly(3-hydroxybutyrate), PHB, and poly(3-hydroxybutyrate-co-23%-3-hydroxyvalerate), PHB/V, by PHB depolymerase B from Pseudomonas lemoignei. The samples examined were thin films of approximately 200 μm thickness produced by melt casting. Since only the amorphous regions of the semicrystalline films contribute to the 1H NMR image intensity, this technique provides unique information regarding the degradation process in the amorphous regions of the films when combined with total weight loss measurements. It was found that although the total weight loss rate of both the PHB and PHB/V films was constant, as previously reported, the initial amorphous material consumption rate was exponential. During the initial stages of the degradation process, up to 40−60 h, preferential consumption of amorphous material by depolymerase B was found to take place. At later stages the preference for amorphous material diminished, and both crystalline and amor...