Thiocyanate (SCN−) is harmful to a wide range of organisms, and its removal is essential for environmental protection. A neutrophilic halophile capable of thiocyanate degradation, Thiohalobacter sp. strain FOKN1, was highly enriched (relative abundance; 98.4%) from activated sludge collected from a bioreactor receiving thiocyanate-rich wastewater. The enrichment culture degraded 3.38 mM thiocyanate within 140 h, with maximum activity at pH 8.8, 37°C, and 0.18 M sodium chloride. Thiocyanate degradation was inhibited by 30 mg L−1 phenol, but not by thiosulfate. Microbial thiocyanate degradation is catalyzed by thiocyanate dehydrogenase, while limited information is currently available on the molecular mechanisms underlying thiocyanate degradation by the thiocyanate dehydrogenase of neutrophilic halophiles. Therefore, (meta)genomic and proteomic analyses of enrichment cultures were performed to elucidate the whole genome sequence and proteome of Thiohalobacter sp. strain FOKN1. The 3.23-Mb circular Thiohalobacter sp. strain FOKN1 genome was elucidated using a PacBio RSII sequencer, and the expression of 914 proteins was identified by tandem mass spectrometry. The Thiohalobacter sp. strain FOKN1 genome had a gene encoding thiocyanate dehydrogenase, which was abundant in the proteome, suggesting that thiocyanate is degraded by thiocyanate dehydrogenase to sulfur and cyanate. The sulfur formed may be oxidized to sulfate by the sequential oxidation reactions of dissimilatory sulfite reductase, adenosine-5′-phosphosulfate reductase, and dissimilatory ATP sulfurylase. Although the Thiohalobacter sp. strain FOKN1 genome carried a gene encoding cyanate lyase, its protein expression was not detectable. The present study advances the understanding of the molecular mechanisms underlying thiocyanate degradation by the thiocyanate dehydrogenase of neutrophilic halophiles.

中文翻译：

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中性嗜盐菌硫氰酸盐杆菌 FOKN1的高度富集培养物降解硫氰酸盐，来自活化污泥和对硫氰酸盐代谢的基因组学洞察

硫氰酸盐 (SCN−) 对多种生物有害，其去除对于环境保护至关重要。一种能够降解硫氰酸盐的嗜中性嗜盐菌，Thiohalobacter sp。FOKN1 菌株从接收富含硫氰酸盐废水的生物反应器收集的活性污泥中高度富集（相对丰度；98.4%）。富集培养物在 140 小时内降解了 3.38 mM 硫氰酸盐，在 pH 8.8、37°C​​ 和 0.18 M 氯化钠条件下具有最大活性。硫氰酸盐降解受 30 mg L-1 苯酚的抑制，但不受硫代硫酸盐的抑制。微生物硫氰酸盐降解由硫氰酸盐脱氢酶催化，而目前关于嗜中性嗜盐菌的硫氰酸盐脱氢酶降解硫氰酸盐的分子机制的信息有限。所以，对富集培养物进行（元）基因组学和蛋白质组学分析，以阐明硫卤杆菌属的全基因组序列和蛋白质组。应变 FOKN1。3.23 Mb 环状硫卤杆菌属。使用 PacBio RSII 测序仪阐明菌株 FOKN1 基因组，并通过串联质谱法鉴定 914 种蛋白质的表达。硫盐杆菌属。FOKN1 菌株基因组中有一个编码硫氰酸脱氢酶的基因，该基因在蛋白质组中含量丰富，表明硫氰酸盐被硫氰酸脱氢酶降解为硫和氰酸盐。形成的硫可以通过异化亚硫酸盐还原酶、腺苷-5'-磷酸硫酸盐还原酶和异化 ATP 硫酸化酶的顺序氧化反应氧化成硫酸盐。虽然硫盐杆菌属。菌株 FOKN1 基因组携带一个编码氰酸裂解酶的基因，检测不到其蛋白表达。本研究促进了对嗜中性嗜盐菌硫氰酸盐脱氢酶降解硫氰酸盐的分子机制的理解。