Mahmoudnia Fahimeh
Department of Biology, Faculty of Sciences, Farhangian University, Tehran, Iran.
Iran J Microbiol. 2021 Jun;13(3):399-406. doi: 10.18502/ijm.v13i3.6403.
Halothermophilic bacteria are adapted to high osmolarity and can grow in high saline environments and high temperatures. This study was aimed at the isolation of halothermophilic bacteria from Howz-e Sultan hypersaline lake in the central desert zone in Iran.
Samples were collected and after preparing dilutions, the samples were cultured on Molten haloid agar with different salt concentrations (5-35%), then the plates were incubated at 35-70ºC in both aerobic and anaerobic conditions. Biochemical characterizations, utilization of carbon sources, production of exoenzymes and antibiotic susceptibility were investigated. Taxonomic and phylogenetic analyses were performed using 16S rRNA gene sequences.
One of the isolated bacteria was found to be Gram-positive, hyperhalophilic, thermophilic, endospore-forming, and was named as 1-9 h isolate. The bacterial cells were bacilli-shaped, which produced endospores at a subterminal position. This isolate was an aerobe and facultative anaerobe and grew between pH 5.0 and 10.0 (optimal growth at pH 7.0-7.5), at temperature between 15°C and 65°C (optimal growth at 40-45°C) and at salinity of 9-32% (w/v) NaCl, growing optimally at 18% (w/v) NaCl. On the basis of 16S rRNA gene sequence analysis, isolate 1-9 h belongs to the genus within the phylum Firmicutes and showed the closest phylogenetic similarity to sp. IBP-V003 (99.0%).
Based on the results of its phenotypic and genotypic properties, strain 1-9 h represents a novel strain of the genus It can be used in various fields of industry and biotechnology.
嗜盐嗜热细菌适应高渗透压，能够在高盐环境和高温下生长。本研究旨在从伊朗中部沙漠地区的豪兹 - 苏丹高盐湖中分离嗜盐嗜热细菌。
采集样本并制备稀释液后，将样本接种于含有不同盐浓度（5 - 35%）的熔融卤化物琼脂上，然后将平板在有氧和无氧条件下于35 - 70ºC孵育。研究了生化特性、碳源利用、胞外酶产生及抗生素敏感性。使用16S rRNA基因序列进行分类和系统发育分析。
分离出的一种细菌为革兰氏阳性、嗜盐嗜热、产芽孢细菌，命名为1 - 9 h分离株。细菌细胞呈杆状，在亚末端位置产生芽孢。该分离株为需氧兼性厌氧菌，在pH 5.0至10.0之间生长（最适生长pH为7.0 - 7.5），温度在15°C至65°C之间（最适生长温度为40 - 45°C），盐度为9 - 32%（w/v）NaCl，在18%（w/v）NaCl时生长最佳。基于16S rRNA基因序列分析，1 - 9 h分离株属于厚壁菌门中的 属，与 sp. IBP - V003显示出最接近的系统发育相似性（99.0%）。
根据其表型和基因型特性的结果，菌株1 - 9 h代表 属的一个新菌株。它可用于工业和生物技术的各个领域。
