Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia.
Department of Microbiology, Chair of Microbial Diversity, Microbiomics and Biotechnology, University of Ljubljana, Biotechnical Faculty, Jamnikarjeva 101, 1000, Ljubljana, Slovenia.
Antonie Van Leeuwenhoek. 2024 Nov 29;118(1):38. doi: 10.1007/s10482-024-02045-w.
The underexplored halophilic genus Joostella within the Flavobacteriaceae family consists of only two species, both of which have received little attention for their potential biotechnological applications. In this study, we report the isolation and characterisation of a novel halophilic bacterium, strain CR20, using a genomic approach to investigate its biotechnological potential. Analysis of the 16S rRNA gene revealed that strain CR20 shares 97.5% and 96.2% sequence similarity with Joostella marina DSM 19592 and Joostella atrarenae M1-2, respectively. Strain CR20 exhibited average nucleotide identity and digital DNA-DNA hybridisation values of 76.8-79.1% and 20.8-22.8%, respectively, with Joostella spp., which fall below the species delineation thresholds. Additionally, strain CR20 demonstrated average amino acid identity and percentage of conserved proteins values of 81.3-84.0% and 71.7-75.3%, respectively, with Joostella spp., above the genus delineation thresholds. Meanwhile, the average amino acid identity and percentage of conserved proteins values of strain CR20 against Galbibacter spp. are 73.9-80.0% and 61.3-72.3%, respectively, also above the genus delineation thresholds. These findings indicated strain CR20 has a close relationship with both genera. Chemotaxonomic analysis of strain CR20 identified predominant fatty acids, including iso-C 3OH (25.3%), iso-C (14%), and C ω6c/C ω7c (12.2%). The assembled genome comprises 62 contigs, with a size of approximately 3,168,727 bp and a G + C content of 35.1%. Among 2,804 predicted genes, 2,559 were classified into 25 COG functional groups. A total of 68 genes with potential industrial applications were identified, including 1 β-mannanase, 2 β-xylosidases, 1 polysaccharide deacetylase, 4 other hemicellulases, 6 β-glucosidases, 25 proteases, and 29 phosphate-solubilising enzymes. Hydrolytic assays confirmed that strain CR20 produces these enzymes extracellularly. These findings highlight strain CR20 has potential for industrial applications.
未充分研究的嗜盐菌属 Joostella 是黄杆菌科的一个仅由两个种组成的属，它们的潜在生物技术应用都很少受到关注。在这项研究中，我们使用基因组方法研究了一种新型嗜盐菌 CR20 的分离和特性，以调查其生物技术潜力。16S rRNA 基因分析表明，CR20 株与 Joostella marina DSM 19592 和 Joostella atrarenae M1-2 的序列相似性分别为 97.5%和 96.2%。CR20 株与 Joostella spp. 的平均核苷酸同一性和数字 DNA-DNA 杂交值分别为 76.8-79.1%和 20.8-22.8%，低于种的划分阈值。此外，CR20 株与 Joostella spp. 的平均氨基酸同一性和保守蛋白百分比分别为 81.3-84.0%和 71.7-75.3%，高于属的划分阈值。同时，CR20 株与 Galbibacter spp. 的平均氨基酸同一性和保守蛋白百分比分别为 73.9-80.0%和 61.3-72.3%，也高于属的划分阈值。这些发现表明 CR20 株与这两个属都有密切的关系。CR20 株的化学生态分析确定了主要脂肪酸，包括 iso-C 3OH（25.3%）、iso-C（14%）和 C ω6c/C ω7c（12.2%）。组装的基因组包含 62 个 contigs，大小约为 3168727 bp，G+C 含量为 35.1%。在 2804 个预测基因中，2559 个被分为 25 个 COG 功能组。共鉴定出 68 个具有潜在工业应用价值的基因，包括 1 个 β-甘露聚糖酶、2 个 β-木糖苷酶、1 个多糖脱乙酰酶、4 个其他半纤维素酶、6 个β-葡萄糖苷酶、25 个蛋白酶和 29 个磷酸溶解酶。水解试验证实 CR20 株可将这些酶分泌到胞外。这些发现突出了 CR20 株具有工业应用的潜力。
