Polycyclic aromatic hydrocarbons (PAHs) are a persistent and prevalent class of pollutants in petroleum-contaminated saline environment, which pose potential harm to organisms. Researches on anaerobic biodegradation of PAHs are gradually emerging, but the response of anaerobic microorganisms to salinity changes and the co-effects of salinity and PAHs in anaerobic digestion (AD) system have seldom been reported. Thus, we investigated the variations of AD system performance and anaerobic microbial community caused by different concentrations of naphthalene (Nap) or/and NaCl based on Box-Behnken Design (0 mg/L ≤ Nap ≤150 mg/L, 0 g/L ≤ NaCl ≤25 g/L). The promoted efficiencies of acidogenesis and methanogenesis were found in presence of moderate NaCl or Nap, but high salinity (NaCl >4.4 g/L) weakened AD performance. Moreover, the high salinity (NaCl >4.4 g/L) and Nap resulted in reduced microbial Ca²⁺ Mg²⁺- ATPase activity, poor EPS secretion and the highest difference of the microbial operational taxonomic units (OTUs), and synergistically inhibited AD process. Microbiological analysis revealed that the relative abundance of Clostridium and acetoclastic Methanosaeta was increased by 2.01 times and 2.17 times in single Nap treated group compared to control. With the simultaneous addition of NaCl and Nap, Proteiniphilum and hydrogenotrophic methanogens (Methanobacterium, Methanofollis, and Methanolinea) occupied the major abundance. Potential functions prediction indicated that high salinity could disrupt the co-metabolism between carbohydrate metabolism and Nap degradation. This study provides basis for anaerobic bioremediation of PAHs-polluted saline environment.

多环芳烃（PAHs）是石油污染的盐碱环境中一类持久存在且普遍存在的污染物，对生物体构成潜在危害。PAHs厌氧生物降解的研究逐渐兴起，但厌氧微生物对盐度变化的响应以及盐度与PAHs在厌氧消化（AD）系统中的共同作用鲜有报道。因此，我们基于 Box-Behnken 设计（0 mg/L ≤ Nap ≤150 mg/L，0 g/L ≤ NaCl ≤25 克/升）。在中等 NaCl 或 Nap 存在下发现酸化和产甲烷效率提高，但高盐度（NaCl > 4.4 g/L）削弱了 AD 性能。而且，²⁺ Mg ²⁺ - ATPase 活性、EPS 分泌不良和微生物操作分类单元（OTU）的最大差异，并协同抑制 AD 过程。微生物学分析表明，与对照组相比，单次 Nap 处理组中梭菌和乙酰碎屑甲烷菌的相对丰度分别增加了 2.01 倍和 2.17 倍。同时添加 NaCl 和 Nap、Proteiniphilum和氢营养型产甲烷菌（Methanobacterium、Methanofollis和Methanolinea) 占据了主要的丰度。潜在功能预测表明，高盐度会破坏碳水化合物代谢和午睡降解之间的共代谢。该研究为多环芳烃污染的盐水环境的厌氧生物修复提供了依据。