Abstract PHB-silver nanocomposite (PHB-AgNc) was synthesized biologically by utilizing a dairy-industry by-product, cheese whey permeate as a substrate for Bacillus megaterium. The single-step synthesis of PHB-AgNc was further confirmed by UV–vis spectroscopy and GC-MS analysis. Further, the extracted PHB-Ag Nc was characterized by employing various techniques such as TEM, SEM, FTIR, NMR, Zeta Potential, and DLS analysis. Mechanical properties such as elongation at break, tensile strength, and Young's Modulus were found to be 1.305%, 35.42, and 1.058 N/mm2, respectively. The nanocomposite was found to be stable, polydispersive, and hydrophobic. It exhibited a degradation temperature of 340 °C and portrayed significant antimicrobial resistance against common food pathogens such as E.coli and Pseudomonas spp. Batch fermentation study was carried out for a period of 96 h in a 14 L bioreactor. The highest biomass and nanocomposite yield obtained was 5.8 and 2.4 g/L, respectively. The highest product productivity concerning biomass was found to be 0.012 h−1 at 12 h. The film's migration properties were tested for various food stimulants, and the values obtained were less than the overall migration limit established for food contact materials; hence, the film was found to be appropriate for food packaging applications.

中文翻译：

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PHB-银纳米复合材料的生物和环境良性合成方法及其表征

摘要 PHB-银纳米复合材料（PHB-AgNc）是通过利用乳制品工业副产品奶酪乳清渗透物作为巨大芽孢杆菌的底物而生物合成的。通过紫外-可见光谱和 GC-MS 分析进一步证实了 PHB-AgNc 的一步合成。此外，提取的 PHB-Ag Nc 通过使用各种技术进行表征，例如 TEM、SEM、FTIR、NMR、Zeta 电位和 DLS 分析。发现断裂伸长率、拉伸强度和杨氏模量等机械性能分别为 1.305%、35.42 和 1.058 N/mm2。发现纳米复合材料是稳定的、多分散的和疏水的。它的降解温度为 340 °C，并对常见的食物病原体（如大肠杆菌和假单胞菌属）表现出显着的抗菌抗性。在 14 L 生物反应器中进行了 96 小时的批量发酵研究。获得的最高生物质和纳米复合材料产量分别为 5.8 和 2.4 g/L。发现关于生物质的最高产品生产力是 12 小时时的 0.012 h-1。对各种食品刺激剂测试了薄膜的迁移性能，所得值低于为食品接触材料制定的总体迁移限值；因此，发现该薄膜适用于食品包装应用。获得的数值低于为食品接触材料制定的总体迁移限值；因此，发现该薄膜适用于食品包装应用。获得的数值低于为食品接触材料制定的总体迁移限值；因此，发现该薄膜适用于食品包装应用。