A polyhydroxyalkanoate (PHA) copolymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)], was biosynthesized from biphenyl as the sole carbon source using Alcaligenes (currently Achromobacter) denitrificans A41. This strain is capable of degrading polychlorinated biphenyls (PCBs) and biphenyl. This proof-of-concept of the conversion of aromatic chemicals such as the environmental pollutant PCBs/biphenyl to eco-friendly products such as biodegradable polyester PHA was inspired by the uncovering of two genes encoding PHA synthases in the A. denitrificans A41 genome. When the carbon/nitrogen (C/N) ratio was set at 21, the cellular P(3HB-co-3HV) content in strain A41 reached its highest value of 10.1% of the cell dry weight (CDW). A two-step cultivation protocol improved the accumulation of P(3HB-co-3HV) by up to 26.2% of the CDW, consisting of 13.0 mol % 3HV when grown on minimum salt medium without nitrogen sources. The highest cellular content of P(3HB-co-3HV) (47.6% of the CDW) was obtained through the two-step cultivation of strain A41 on biphenyl as the sole carbon source. The purified copolymer had ultra-high molecular weight (weight-average molecular weight of 3.5 × 10⁶), as revealed through gel-permeation chromatography. Based on the genomic information related to both polymer synthesis and biphenyl degradation, we finally proposed a metabolic pathway for the production of P(3HB-co-3HV) associated with the degradation of biphenyl by strain A41.

中文翻译：

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脱氮产碱菌 A41 将联苯生物转化为聚羟基链烷酸酯共聚物。

使用Alcaligenes（目前为Achromobacter）脱氮菌A41 ，以联苯为唯一碳源，生物合成聚羟基烷酸酯（PHA）共聚物，聚（3-羟基丁酸酯-co -3-羟基戊酸酯）[P(3HB- co -3HV)] 。该菌株能够降解多氯联苯 (PCB) 和联苯。将环境污染物 PCB/联苯等芳香族化学物质转化为可生物降解聚酯 PHA 等环保产品的这一概念验证的灵感来自于脱氮放线菌A41基因组中编码 PHA 合酶的两个基因的发现。当碳/氮(C/N)比设置为21时，菌株A41中细胞P(3HB- co -3HV)含量达到最高值，为细胞干重(CDW)的10.1%。当在没有氮源的最低盐培养基上生长时，两步培养方案将 P(3HB- co -3HV) 的积累提高了 CDW 的 26.2%，其中包括 13.0 mol% 3HV。通过以联苯为唯一碳源对菌株 A41 进行两步培养，获得了最高的 P(3HB- co -3HV) 细胞含量（CDW 的 47.6%）。通过凝胶渗透色谱法表明，纯化的共聚物具有超高分子量(重均分子量为3.5×10 ^{6 )。}基于与聚合物合成和联苯降解相关的基因组信息，我们最终提出了菌株A41产生与联苯降解相关的P(3HB- co -3HV)的代谢途径。