Hexabromocyclododecane (HBCD) is a typical persistent organic pollutant that is widely detected in the environment. Despite the significant efforts put into its mineralisation, there is still a lack of microorganism resources that can completely mineralise HBCD. Stable isotope analysis revealed that the Citrobacter sp. Y3 can use [¹³C]HBCD as its sole carbon source and degrade or even mineralise it into ¹³CO₂, with a maximum conversion rate of 100% in approximately 14 days. Strain Y3 could completely mineralise HBCD, which it used as its only carbon source, and six debromination enzymes related to HBCD degradation were found in Y3, including haloalkane dehalogenase (DhaA), haloacid dehalogenase (HAD), etc. A functional gene named HBCD-hd-1, encoding a HAD, was found to be upregulated during HBCD degradation and heterologously expressed in Escherichia coli. Recombinant E. coli with the HBCD-hd-1 gene transformed the typical intermediate 4-bromobutyric acid to 4-hydroxybutanoic acid and showed excellent degradation performance on HBCD, accompanied by nearly 100% bromine (Br) ion generation. The expression of HBCD-hd-1 in Y3 rapidly accelerated the biodegradation of HBCD. With HBCD as its sole carbon source, strain Y3 could potentially degrade HBCD, especially in a low-nutrient environment.

六溴环十二烷（HBCD）是一种典型的持久性有机污染物，在环境中被广泛检测到。尽管在其矿化方面付出了巨大努力，但仍然缺乏可以完全矿化六溴环十二烷的微生物资源。稳定同位素分析表明，柠檬酸杆菌属sp 。Y3可以使用[ ¹³ C]HBCD作为其唯一的碳源，并将其降解甚至矿化成¹³ CO ₂，在大约 14 天内最高转化率为 100%。菌株Y3可以完全矿化作为其唯一碳源的六溴环十二烷，在Y3中发现了六种与六溴环十二烷降解相关的脱溴酶，包括卤代烷脱卤酶（DhaA）、卤酸脱卤酶（HAD）等。功能基因HBCD-发现编码 HAD 的hd-1在 HBCD 降解过程中上调，并在大肠杆菌中异源表达。带有HBCD-hd-1基因的重组大肠杆菌将典型的中间体 4-溴丁酸转化为 4-羟基丁酸，对 HBCD 表现出优异的降解性能，同时产生近 100% 的溴 (Br) 离子。HBCD-hd-1的表达Y3 迅速加速了六溴环十二烷的生物降解。以六溴环十二烷为唯一碳源，Y3 菌株可能会降解六溴环十二烷，尤其是在低营养环境中。