Abstract

Hypersaline environment is a habitat with extreme osmotic conditions along with low A_w, serving as a home to extremely halophilic and halotolerant bacteria. The hypersaline environments, such as solar salterns located along the rivers, are exposed to fluxes of iron from iron ore transportation and other industrial wastes. The solar salterns often serve as a sink for metal intoxicants. Studies on archaea interaction with metal ions indicate the formation of minerals such as goethite, hematite, rhodochrosite, etc. However, studies exploring haloarchaeal candidates interacting with metals such as Fe³⁺ in a hypersaline growth condition are scarce. This study unveils for the first time formation of γFe₂O₃ from Fe³⁺ by the haloarchaeon, Haloferax sp. GUSF-1 thus implying the significance of the culture synthesizing minerals in hypersaline sediments. γFe₂O₃ is formed from Fe³⁺ by the haloarchaeon Haloferax sp. GUSF-1 (GenBank accession no.GU-1KF796625), under microaerophilic growth on sodium acetate. A 50 mg L⁻¹ of Fe²⁺ and 30.6 mg L⁻¹ of Fe³⁺ was detected inside the cells. Simultaneously, a brown-colored crystalline material deposited in the culture broth through an iron reductase inhibited by Zn²⁺ ions. The XRD of the deposit exhibited d values of 2.96, 2.514, 2.086, 1.6, and 1.45, while SEM-EDX displayed cubic and irregularly shaped minute particles with peaks for Fe at 0.6, 6.4, and 6.6 keV, respectively. TEM profiles revealed polycrystalline particles of 12–23 nm in size. Further, the SAED concentric pattern of light scattering with well-defined diffraction spots was consistent and matched with maghemite's crystal structure (γFe₂O₃). The FTIR spectrum revealed a peak at 1450 cm⁻¹ indicating iron oxyhydroxide formation as an intermediate having γ-FeOOH stretching bond vibrations. Conclusively, this study opens the possibility of the haloarchaea isolated from solar salterns for its exploitation in nanobiotechnology.

摘要

高盐环境是具有极端渗透条件和低 A _w的栖息地，是极端嗜盐和耐盐细菌的家园。高盐度环境，例如位于河流沿岸的太阳能盐场，暴露于来自铁矿石运输和其他工业废物的铁通量。日光盐浴通常用作金属麻醉剂的水槽。对古菌与金属离子相互作用的研究表明，形成了针铁矿、赤铁矿、菱锰矿等矿物质。然而，在高盐度生长条件下探索与 Fe ³⁺等金属相互作用的卤古菌候选物的研究很少。该研究首次揭示了从 Fe ³⁺形成 γFe ₂ O ₃由haloarchaeon，Haloferax sp。GUSF-1 因此暗示了在高盐度沉积物中合成矿物质的培养物的重要性。γFe ₂ O ₃是由 Fe ³⁺由卤古菌 Haloferax sp 形成的。GUSF-1（GenBank 登录号 GU-1KF796625），在醋酸钠上微需氧生长。在细胞内检测到50mg L ^-1的Fe ²⁺和30.6mg L ^-1的Fe ³⁺。同时，棕色结晶物质通过受 Zn ²⁺离子抑制的铁还原酶沉积在培养液中。沉积物的 XRD 显示d值分别为 2.96、2.514、2.086、1.6 和 1.45，而 SEM-EDX 显示立方体和不规则形状的微小颗粒，Fe 的峰值分别为 0.6、6.4 和 6.6 keV。TEM 剖面显示大小为 12-23 nm 的多晶颗粒。此外，具有明确衍射点的光散射的 SAED 同心圆图案与磁赤铁矿的晶体结构 (γFe ₂ O ₃ )一致并匹配。FTIR 光谱显示在 1450 cm ^-1处有一个峰，表明羟基氧化铁形成为具有 γ-FeOOH 伸缩键振动的中间体。总而言之，这项研究开启了从太阳盐场中分离出盐古菌以用于纳米生物技术开发的可能性。