A set of 110 extremely halophilic archaeal strains were isolated from seven distinct saline habitats located in different regions of Algeria. The physicochemical characterization of the samples showed that these habitats were thalassohaline. The carotenoid production from isolated strains varied from 0.1 to 3.68 µg/ml. Based on their physiological characteristics and pigment production, 43 strains were selected and identified by means of phenotypic tests and 16S ribosomal RNA gene sequencing. Phylogenetic analysis indicated that the isolates corresponded to the class Halobacteria and were closely related to genera Halorubrum, Haloarcula, Haloferax, Natrinema, Halogeometricum, Haloterrigena, and Halopiger. Carotenoids of the highest producer, strain Halorubrum sp. BS2 were identified using high‐performance liquid chromatography–diode array detector and liquid chromatography–mass spectrometry. Bacterioruberin and bisanhydrobacterioruberin were the predominant carotenoids. The scavenging activity of these carotenoids reached 99% at a concentration of 18 μg/ml, which was much higher than that of ascorbic acid used as a reference compound. These carotenoids also exhibited significant antibacterial activities against four human‐pathogenic strains and four fish‐pathogenic strains. Variations in salinity, agitation rate, temperature, and light intensity were found to influence growth and carotenoid production of Halorubrum sp. BS2. Our results suggest that halophilic archaea represent a potential source for carotenoids, which are characterized by high antioxidant and antibacterial activities.

中文翻译：

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通过分析 Halorubrum sp. 产生的类胡萝卜素，对来自阿尔及利亚高盐环境的有色嗜盐古菌菌株进行生物勘探和表征。BS2

从位于阿尔及利亚不同地区的七个不同的盐水栖息地中分离出一组 110 种极端嗜盐古菌菌株。样品的理化特性表明这些栖息地是海水盐碱地。来自分离菌株的类胡萝卜素产量从 0.1 到 3.68 µg/ml 不等。根据其生理特征和色素产生情况，通过表型试验和16S核糖体RNA基因测序，筛选鉴定出43株菌株。系统发育分析表明，这些分离物属于 Halobacteria 纲，与 Halorubrum、Haloarcula、Haloferax、Natrinema、Halogeometricum、Haloterrigena 和 Halopiger 属密切相关。最高生产者的类胡萝卜素，菌株 Halorubrum sp。BS2 使用高效液相色谱-二极管阵列检测器和液相色谱-质谱法进行鉴定。Bacterioruberin 和bisanhydrobacterioruberin 是主要的类胡萝卜素。这些类胡萝卜素的清除活性在 18 μg/ml 的浓度下达到 99%，远高于用作参考化合物的抗坏血酸。这些类胡萝卜素还对四种人类致病菌株和四种鱼类致病菌株表现出显着的抗菌活性。发现盐度、搅拌速率、温度和光照强度的变化会影响 Halorubrum sp. 的生长和类胡萝卜素的产生。BS2。我们的研究结果表明，嗜盐古细菌是类胡萝卜素的潜在来源，其特点是具有高抗氧化和抗菌活性。