Zhang Dao-Feng, Wang Hong-Chuan, Shi Shi, Li Tian-Pu, Guo Dan-Yuan, Yang Zi-Wen, Yuan Yang, Huang Jianke, Li Wen-Jun
Jiangsu Province Engineering Research Center for Marine Bio-resources Sustainable Utilization & College of Oceanography, Hohai University, Nanjing, PR China.
Jiangsu Province Engineering Research Center for Marine Bio-resources Sustainable Utilization & College of Oceanography, Hohai University, Nanjing, PR China; State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China.
Syst Appl Microbiol. 2025 Jul;48(4):126624. doi: 10.1016/j.syapm.2025.126624. Epub 2025 Jun 4.
Bacteria are considered as better models for industrial production of astaxanthin (AXT) because of their fast growth and convenience for the downstream extraction. Nevertheless, few bacterial species of native AXT producers are explored to date. In this study, bacterial strains XHP0235 (=GDMCC 1.3093 = MCCC 1K07532 = JCM 35574) and XHP0239 (=GDMCC 1.3086 = MCCC 1K07530 = JCM 35575) were isolated from coastal seawater of China. Polyphasic taxonomy suggested that strains XHP0235 and XHP0239 were closely related to Sphingomicrobium aestuariivivum AH-M8, S. arenosum CAU 1457, and S. astaxanthinifaciens CC-AMO-30B, and should be recognized as two novel species of the genus Sphingomicrobium, for which the names Sphingomicrobium aquimarinum sp. nov. and Sphingomicrobium maritimum sp. nov. are proposed, respectively. Comparative genomic analysis revealed the complete AXT pathway (genes crtB, crtI, crtY, crtZ, and crtW) present in strains XHP0235, XHP0239 and the three relative strains, and the carotenoid-targeted metabolome analysis confirmed the productions of AXT and other carotenoids. Inspired by these findings, the AXT pathway was further explored in the family Sphingomonadaceae, and 45 (18.8 %) out of the 240 type strains was identified to harbor all the five genes for AXT synthesis, of which the gene arrangement can be classified as seven types. The flanking gene contents were extremely variable with a concerted evolutionary history of the AXT genes. However, the AXT pathway is still predictable if an isolate is closely related to a known AXT-pathway-positive strain (evolutionary distance <0.14). This study significantly enlarged the diversity of AXT-producing bacteria with highlighting such species in the family Sphingomonadaceae.
由于细菌生长迅速且便于下游提取，因此被认为是虾青素（AXT）工业化生产的更佳模型。然而，迄今为止，很少有天然AXT生产细菌物种被探索。在本研究中，从中国沿海海水中分离出细菌菌株XHP0235（=GDMCC 1.3093 = MCCC 1K07532 = JCM 35574）和XHP0239（=GDMCC 1.3086 = MCCC 1K07530 = JCM 35575）。多相分类法表明，菌株XHP0235和XHP0239与河口鞘氨醇单胞菌AH-M8、沙质鞘氨醇单胞菌CAU 1457和产虾青素鞘氨醇单胞菌CC-AMO-30B密切相关，应被认定为鞘氨醇单胞菌属的两个新物种，分别命名为海洋鞘氨醇单胞菌（Sphingomicrobium aquimarinum sp. nov.）和海洋鞘氨醇单胞菌（Sphingomicrobium maritimum sp. nov.）。比较基因组分析揭示了菌株XHP0235、XHP0239以及三个相关菌株中存在完整的AXT途径（基因crtB、crtI、crtY、crtZ和crtW），并且类胡萝卜素靶向代谢组分析证实了AXT和其他类胡萝卜素的产生。受这些发现的启发，在鞘氨醇单胞菌科中进一步探索了AXT途径，在240株模式菌株中，有45株（18.8%）被鉴定含有所有五个AXT合成基因，其基因排列可分为七种类型。侧翼基因内容极具变异性，AXT基因具有协同进化历史。然而，如果一个分离株与已知的AXT途径阳性菌株密切相关（进化距离<0.14），AXT途径仍然是可预测的。本研究显著扩大了产AXT细菌的多样性，突出了鞘氨醇单胞菌科中的此类物种。
