School of Life Sciences, Northeast Normal University, Changchun 130024, China.
World J Microbiol Biotechnol. 2012 Oct;28(10):2929-35. doi: 10.1007/s11274-012-1103-5. Epub 2012 Jun 19.
In this study, fungi isolated from soil were screened for their ability to form clear zones on agar plates with emulsified poly(ε-caprolactone) (PCL). The most active strain, designated as DSYD05, was identified as Penicillium oxalicum on the basis of morphological characteristics and phylogenetic analysis. Mutant DSYD05-1, obtained by ultraviolet-light mutagenesis from strain DSYD05, was more effective in PCL degradation. In liquid cultures of the mutant strain with PCL emulsion, DSYD05-1 showed the highest PCL-degrading activity after 4 days of cultivation. The products of PCL degradation were analysed by mass spectrometry; the results indicated that 6-hydroxyhexanoic acid was produced and assimilated during cultivation. The degradation of PCL film by DSYD05-1 was observed by scanning electron microscopy, and was indicative of a three-stage degradation process. The degradation of amorphous parts of the film preceded that of the crystalline center and then the peripheral crystalline regions. In addition, DSYD05-1 showed a wide range of substrate specificity, with capability to degrade PCL, poly(β-hydroxybutyrate), and poly(butylene succinate), but not poly(lactic acid), indicating that the strain could have potential for application in the treatment or recycling of bio-plastic wastes.
在这项研究中，从土壤中分离出的真菌被筛选出来，以评估其在含有乳化聚己内酯（PCL）的琼脂平板上形成透明区域的能力。最活跃的菌株被命名为 DSYD05，根据形态特征和系统发育分析，被鉴定为草酸青霉。从 DSYD05 菌株通过紫外线诱变获得的突变株 DSYD05-1 在 PCL 降解方面更有效。在含有 PCL 乳液的突变株液体培养中，DSYD05-1 在培养 4 天后显示出最高的 PCL 降解活性。通过质谱分析对 PCL 降解产物进行了分析；结果表明，在培养过程中产生并同化了 6-羟基己酸。通过扫描电子显微镜观察到 DSYD05-1 对 PCL 薄膜的降解，表明降解过程经历了三个阶段。薄膜无定形部分的降解先于结晶中心，然后是周边结晶区域。此外，DSYD05-1 表现出广泛的底物特异性，能够降解 PCL、聚（β-羟基丁酸酯）和聚丁二酸丁二醇酯，但不能降解聚乳酸，表明该菌株在生物塑料废物的处理或回收方面具有应用潜力。
