Cadmium (Cd) and chromium (Cr) are widespread contaminants with a high risk to the environment and humans. Herein we isolated a novel strain of Serratia marcescens, namely strain S27, from soil co-contaminated with Cd and Cr. This strain showed strong resistance to Cd as well as Cr. S27 cells demonstrated Cd adsorption rate of 45.8% and Cr reduction capacity of 84.4% under optimal growth conditions (i.e., 30 °C, 200 rpm, and pH 7.5). Microscopic characterization of S27 cells revealed the importance of the functional groups C–O–C, C–H–O, C–C, C–H, and –OH, and also indicated that Cr reduction occurred on bacterial cell membrane. Cd(II) and Cr(VI) bioaccumulation on S27 cell surface was mainly in the form of Cd(OH)₂ and Cr₂O₃, respectively. Further, metabolomic analyses revealed that N-arachidonoyl-l-alanine was the key metabolite that promoted Cd and Cr complexation by S27; it primarily promotes γ-linolenic acid (GLA) metabolism, producing siderophores and coordinating with organic acids to enhance metal bioavailability. To summarize, our results suggest that S27 is promising for the bioremediation of environments contaminated with Cd and Cr in tropical regions.

镉 (Cd) 和铬 (Cr) 是广泛存在的污染物，对环境和人类具有高风险。在这里，我们从被 Cd 和 Cr 共同污染的土壤中分离出一株新的粘质沙雷氏菌菌株，即菌株 S27。该菌株对 Cd 和 Cr 表现出很强的抗性。S27 细胞在最佳生长条件（即 30 °C、200 rpm 和 pH 7.5）下表现出 45.8% 的 Cd 吸附率和 84.4% 的 Cr 还原能力。S27 细胞的显微表征揭示了官能团 C–O–C、C–H–O、C–C、C–H 和 –OH 的重要性，并且还表明 Cr 还原发生在细菌细胞膜上。Cd(II)和Cr(VI)在S27细胞表面的生物富集主要以Cd(OH) ₂和Cr ₂ O _{3的形式存在}， 分别。此外，代谢组学分析表明，N-花生四烯酰基-l-丙氨酸是通过 S27 促进 Cd 和 Cr 络合的关键代谢物；它主要促进γ-亚麻酸（GLA）代谢，产生铁载体并与有机酸协调以提高金属生物利用度。总而言之，我们的结果表明 S27 有望用于热带地区受 Cd 和 Cr 污染的环境的生物修复。