To establish bioplastics as a real alternative to conventional plastics, high production costs must be constrained by using different kinds of wastewater streams as organic substrates and novel microbial strains as material-accumulating bacteria with high performance. Volatile fatty acids (VFAs) from the effluent of dairy wastewater biodigestion represent a new and inexpensive feedstock, which was used in this study for biopolymer production through microbial processes. Cupriavidus necator DSM 13513 was particularly able to accumulate PHAs when operating in fed-batch mode by limiting the oxygen level together with intermittent feeding of a carbon source; maximum poly-β-hydroxybutyrate (PHB) accumulation was achieved in 48 h without compromising microbial growth. The complex VFAs mixture from the digestate did not influence PHA homopolymer accumulation. In fact, structural characterization by NMR analysis revealed PHB synthesis by C. necator DSM 13513 grown with different VFAs mixtures. Moreover, the bioplastic disk obtained from C. necator DSM 13513 cells grown on VFAs from digested dairy wastewater effluent presented good thermic properties and low affinity to water. Overall, the results make digested dairy wastewater effluent suitable for PHB production for specific biobased industrial applications.

中文翻译：

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乳制品废水中的聚羟基链烷酸酯（PHA）：细菌积累，结构表征和物理性质

为了将生物塑料确立为传统​​塑料的真正替代品，必须通过使用不同种类的废水流作为有机底物和使用新型微生物菌株作为高性能的材料积累细菌来限制高生产成本。奶牛场废水生物消化过程中产生的挥发性脂肪酸（VFA）代表了一种新型且廉价的原料，该原料在本研究中用于通过微生物过程生产生物聚合物。在以分批补料模式运行时，铜氧菊酯除臭剂DSM 13513能够通过限制氧气含量和碳源的间歇补给来积累PHAs。在48小时内达到最大的聚-β-羟基丁酸酯（PHB）积累，而不会损害微生物的生长。消化物中的复杂VFA混合物不影响PHA均聚物的积累。实际上，通过NMR分析的结构表征揭示了C. necator DSM 13513与不同的VFA混合物一起生长时的PHB合成。此外，从生长在VFA上的C. necator DSM 13513细胞获得的生物塑料盘，来自消化的乳制品废水流出物，具有良好的热学性质，并且对水的亲和力低。总体而言，结果使消化后的乳制品废水适合于特定生物基工业应用的PHB生产。在消化的乳制废水中的VFA上生长的necator DSM 13513细胞具有良好的热学性质，并且对水的亲和力较低。总体而言，结果使消化后的乳制品废水适合于特定生物基工业应用的PHB生产。在消化的乳制废水中的VFA上生长的necator DSM 13513细胞具有良好的热学性质，并且对水的亲和力较低。总体而言，结果使消化后的乳制品废水适合于特定生物基工业应用的PHB生产。