Abosamaha Abdolkader, Williamson Mike P, Gilmour D James
School of Science and Technology, Nottingham Trent University, Nottingham NG11 8NS, UK.
Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
Access Microbiol. 2022 May 11;4(5):acmi000359. doi: 10.1099/acmi.0.000359. eCollection 2022 Aug.
When grown in high salt concentrations, halophilic bacteria often accumulate compatible solutes, which have major applications in biotechnology because they stabilize cells and proteins. Four Gram-negative bacterial strains, belonging to the family were isolated from Qaberoun and Um-Alma lakes in South Libya using high-salinity medium. The strains were identified using 16S rRNA gene sequencing as belonging to (strain ABQ1) (ABQ2), (ABU1) and (ABU2). ABQ1 is a moderate halophile (salinity range 0.05 to 2.5 M NaCl), with a broad tolerance to pH (7 to 9) and temperature (25-37 °C). Addition of the compatible solutes glycine betaine (betaine) and ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid) to the medium had a positive effect on growth of at 2 M NaCl. In rich LB medium, betaine was the major compatible solute accumulated, with ectoine only being accumulated at salinities in excess of 1 M NaCl. In minimal M9 medium, betaine was not produced, but increasing amounts of ectoine were synthesized with increasing salinity, and hydroxyectoine [(4S,5S)-5-hydroxy-2-methyl-1,4,5,6-tetrahydropyrimidine-4-carboxylic acid] was also synthesized when the cells were grown in very high salt. We have thus identified as a producer of ectoine and hydroxyectoine, with more being produced at higher salinities. As industrial demand for these compatible solutes continues to increase, this system has biotechnological potential.
嗜盐细菌在高盐浓度环境中生长时，通常会积累相容性溶质，这些溶质在生物技术领域具有重要应用，因为它们能稳定细胞和蛋白质。使用高盐培养基从利比亚南部的卡贝鲁恩湖和乌姆 - 阿尔马湖分离出了四株革兰氏阴性细菌菌株，它们属于[具体科名未给出]科。通过16S rRNA基因测序鉴定这些菌株分别属于[具体属名未给出]（菌株ABQ1）、[具体属名未给出]（ABQ2）、[具体属名未给出]（ABU1）和[具体属名未给出]（ABU2）。ABQ1是中度嗜盐菌（盐度范围为0.05至2.5 M NaCl），对pH值（7至9）和温度（25 - 37°C）具有广泛的耐受性。向培养基中添加相容性溶质甘氨酸甜菜碱（甜菜碱）和四氢嘧啶（1,4,5,6 - 四氢 - 2 - 甲基 - 4 - 嘧啶羧酸）对ABQ1在2 M NaCl条件下的生长有积极影响。在丰富的LB培养基中，甜菜碱是积累的主要相容性溶质，只有在盐度超过1 M NaCl时才会积累四氢嘧啶。在基本的M9培养基中，不产生甜菜碱，但随着盐度增加会合成越来越多的四氢嘧啶，并且当细胞在极高盐环境中生长时还会合成羟基四氢嘧啶[（4S,5S） - 5 - 羟基 - 2 - 甲基 - 1,4,5,6 - 四氢嘧啶 - 4 - 羧酸]。因此，我们确定ABQ1是四氢嘧啶和羟基四氢嘧啶的生产者，在更高盐度下会产生更多。随着工业对这些相容性溶质的需求持续增加，该系统具有生物技术潜力。
