A new genus Paramaribius gen. nov. with a new moderately halophilic species isolated from the surface of a polyethylene microplastic particle after incubation in a marine aquaria system

A bacterial strain, designated THAF1T, was isolated from the surface of a polyethylene microplastic particle after incubation in a marine microcosm containing several corals fragments. The strain was strictly aerobic and showed a pale-orange colour; cells were rod-shaped, Gram-stain negative, and non-motile. Phylogenetic analysis based on the nearly full-length 16S rRNA gene sequence placed the strain within family Rhodobacteraceae in between the genera Pseudomaribius, Palleronia, and Maribius. Strain THAF1T exhibited highest 16S rRNA gene sequence similarity to type strains of the species Maribius pontilimi (97.0 %), Pseudomaribius aestuariivivens (96.7 %), and Palleronia abyssalis (95.7 %). Strain THAF1T grew between 15 and 37 °C, in the presence of 1 to 12 % NaCl, and at pH 4.5 to 10.0. The predominant ubiquinone was Q-10 and the major cellular fatty acids were C18:1?7c (61.1 %) and cyclo C19:0?8c (20.0 %). The polar lipid profile contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, three aminolipids, one phospholipid, two lipids lacking a functional group and one glycolipid. Analysis of polyamine content showed that the major component was spermidine. The genomic DNA G+C content was 60.1 mol %. According to the evidence of the phylogenetic, chemotaxonomic, and phenotypic analyses, strain THAF1T is a member of a novel genus within the Rhodobacteraceae.

一株命名为THAF1T的细菌菌株，是在含有多块珊瑚碎片的海洋微宇宙体系中孵育后，从聚乙烯微塑料颗粒的表面分离得到的。该菌株为严格需氧菌，菌落呈浅橙色；细胞呈杆状、革兰氏染色阴性且无运动性。基于近乎全长的16S rRNA基因（16S rRNA gene）序列的系统发育分析表明，该菌株隶属于红杆菌科（Rhodobacteraceae），其系统发育地位处于假海单胞菌属（Pseudomaribius）、帕拉氏菌属（Palleronia）与海单胞菌属（Maribius）之间。菌株THAF1T的16S rRNA基因序列与以下模式菌株的最高相似率分别为：马里比乌斯菌（Maribius pontilimi）97.0%、海滨假海单胞菌（Pseudomaribius aestuariivivens）96.7%以及深渊帕拉氏菌（Palleronia abyssalis）95.7%。菌株THAF1T的生长温度范围为15℃至37℃，可在1%至12%的NaCl浓度下生长，适宜pH范围为4.5至10.0。其主要泛醌（ubiquinone）为Q-10，主要细胞脂肪酸成分为C18:1 ω7c（61.1%）与环丙基C19:0 ω8c（20.0%）。该菌株的极性脂谱包含磷脂酰甘油、双磷脂酰甘油、磷脂酰胆碱、三种氨基脂、一种磷脂、两种不含官能团的脂类以及一种糖脂。多胺含量分析结果显示，其主要多胺成分为亚精胺（spermidine）。该菌株的基因组DNA G+C摩尔含量为60.1 mol%。综合系统发育、化学分类学与表型分析的相关证据，菌株THAF1T隶属于红杆菌科下的一个全新属。