van Vliet Daan M, Palakawong Na Ayudthaya Susakul, Diop Sally, Villanueva Laura, Stams Alfons J M, Sánchez-Andrea Irene
Laboratory of Microbiology, Wageningen University, Wageningen, Netherlands.
Thailand Institute of Scientific and Technological Research, Pathum Thani, Thailand.
Front Microbiol. 2019 Feb 18;10:253. doi: 10.3389/fmicb.2019.00253. eCollection 2019.
The marine environment contains a large diversity of sulfated polysaccharides and other glycopolymers. Saccharolytic microorganisms degrade these compounds through hydrolysis, which includes the hydrolysis of sulfate groups from sugars by sulfatases. Various marine bacteria of the (PVC) superphylum have exceptionally high numbers of sulfatase genes associated with the degradation of sulfated polysaccharides. However, thus far no sulfatase-rich marine anaerobes are known. In this study, we aimed to isolate marine anaerobes using sulfated polysaccharides as substrate. Anoxic enrichment cultures were set up with a mineral brackish marine medium, inoculated with anoxic Black Sea sediment sampled at 2,100 m water depth water and incubated at 15°C ( = 8°C) for several weeks. Community analysis by 16S rRNA gene amplicon sequencing revealed the enrichment of clade R76-B128 bacteria in the enrichments with the sulfated polysaccharides fucoidan and iota-carrageenan as substrate. We isolated two strains, F1 and F21, which represent a novel family within the order of the . They were capable of growth on various mono-, di-, and polysaccharides, including fucoidan. The desulfation of iota-carrageenan by strain F21 was confirmed quantitatively by an increase in free sulfate concentration. Strains F1 and F21 represent the first marine sulfatase-rich anaerobes, encoding more sulfatases (521 and 480, 8.0 and 8.4% of all coding sequences, respectively) than any other microorganism currently known. Specific encoded sulfatase subfamilies could be involved in desulfating fucoidan (S1_15, S1_17 and S1_25) and iota-carrageenan (S1_19). Strains F1 and F21 had a sulfatase gene classification profile more similar to aerobic than anaerobic sulfatase-rich PVC bacteria, including , the only other cultured representative within the . Both strains encoded a single anaerobic sulfatase-maturating enzyme which could be responsible for post-translational modification of formylglycine-dependent sulfatases. Strains F1 and F21 are potential anaerobic platforms for future studies on sulfatases and their maturation enzymes.
海洋环境中含有多种硫酸化多糖和其他糖聚合物。糖分解微生物通过水解作用降解这些化合物，其中包括硫酸酯酶将糖上的硫酸基团水解。聚氯乙烯（PVC）超群的各种海洋细菌具有与硫酸化多糖降解相关的大量硫酸酯酶基因。然而，迄今为止，尚未发现富含硫酸酯酶的海洋厌氧菌。在本研究中，我们旨在以硫酸化多糖为底物分离海洋厌氧菌。使用矿物微咸海洋培养基建立缺氧富集培养物，接种在2100米水深采集的缺氧黑海沉积物，并在15°C（=8°C）下培养数周。通过16S rRNA基因扩增子测序进行群落分析，结果显示在以硫酸化多糖岩藻依聚糖和ι-卡拉胶为底物的富集培养物中，R76-B128进化枝细菌得到了富集。我们分离出了两株菌株，F1和F21，它们代表了该目内的一个新科。它们能够在包括岩藻依聚糖在内的各种单糖、二糖和多糖上生长。通过游离硫酸盐浓度的增加定量证实了菌株F21对ι-卡拉胶的脱硫作用。菌株F1和F21是首批富含海洋硫酸酯酶的厌氧菌，其编码的硫酸酯酶数量（分别为521个和480个，占所有编码序列的8.0%和8.4%）比目前已知的任何其他微生物都多。特定编码的硫酸酯酶亚家族可能参与岩藻依聚糖（S1_15、S1_17和S1_25）和ι-卡拉胶（S1_19）的脱硫。菌株F1和F21的硫酸酯酶基因分类图谱与富含硫酸酯酶的需氧PVC细菌比厌氧PVC细菌更为相似，包括该目内唯一的其他培养代表。两株菌株都编码一种单一的厌氧硫酸酯酶成熟酶，该酶可能负责甲酰甘氨酸依赖性硫酸酯酶的翻译后修饰。菌株F1和F21是未来研究硫酸酯酶及其成熟酶的潜在厌氧平台。
