Biosurfactant - Rhamnolipids (RLs) and antibacterial toxin - pyocyanin (PYO) produced by Pseudomonas aeruginosa strains have great potential for biotechnological applications. Generally, RLs are produced as a mixture of di-rhamnolipids (di-RLs) and mono-rhamnolipids (mono-RLs). Mono-RLs possess superior emulsification and antimicrobial properties and are costlier than di-RLs. In this study, a taxonomic outlier P. aeruginosa strain CR1 isolated from rhizosphere soil was explored for mono-RLs and PYO production. Phylogenetically strain CR1 resembles avirulent outlier P. aeruginosa strain ATCC9027, lacks archetypical virulence genes and harbors unique pathways for the synthesis of solely mono-RLs and PYO. Strain CR1 produced RL biosurfactant which efficiently emulsified hydrocarbons, showed hemolysis and inhibited Bacillus subtilis. At 37 °C, strain CR1 exclusively produced 21.77 g L-1 and 19.22 g L-1 rhamnolipid in glycerol amended Luria Bertani (LB) medium and basal medium amended with rice bran oil, respectively after 54 h growth. Besides RL production was unaffected under varying nitrogen sources. Structural characterization using FTIR, TLC, and LC-MS confirmed that strain CR1 exclusively produced mono-RLs, majorly dominated by Rha-C10-C10, Rha-C10-C8, and CH3-Rha-C12:2-C10:1. The compound was stable over a wide pH range (4-12), salinity (25%) and 100 °C indicating its applicability under harsh environmental conditions. In addition, strain CR1 produced 4.5 μg mL-1 PYO, which could efficiently inhibit biofilm formation by Bacillus species. The environmental outlier strain CR1 can be used for the industrial production of biotechnologically important mono-RLs and PYO.

中文翻译：

---

分类学异常值铜绿假单胞菌菌株CR1快速单生生产鼠李糖脂生物表面活性剂和生物膜抑制绿脓素。

铜绿假单胞菌菌株生产的生物表面活性剂-鼠李糖脂（RLs）和抗菌毒素-绿脓素（PYO）在生物技术应用方面具有巨大潜力。通常，RL以双鼠李糖脂（di-RLs）和单鼠李糖脂（mono-RLs）的混合物形式生产。Mono-RLs具有优异的乳化和抗菌性能，并且比di-RLs昂贵。在这项研究中，从根际土壤中分离出一个分类学上异常的铜绿假单胞菌菌株CR1，以研究单RLs和PYO的产生。系统发育上的CR1菌株类似于无毒的异常铜绿假单胞菌菌株ATCC9027，缺少原型毒力基因，并且具有唯一的单RLs和PYO合成途径。CR1菌株生产的RL生物表面活性剂可有效乳化碳氢化合物，显示溶血作用并抑制枯草芽孢杆菌。在37°C下，菌株CR1在生长54小时后，分别在甘油改良的Luria Bertani（LB）培养基和米糠油改良的基础培养基中分别产生21.77 g L-1和19.22 g L-1鼠李糖脂。此外，在不同的氮源下，RL的生产不受影响。使用FTIR，TLC和LC-MS进行结构表征证实，菌株CR1专门产生了单价RL，主要由Rha-C10-C10，Rha-C10-C8和CH3-Rha-C12：2-C10：1主导。该化合物在很宽的pH范围（4-12），盐度（25％）和100°C下均稳定，表明其在恶劣的环境条件下的适用性。此外，菌株CR1产生4.5μgmL-1 PYO，可以有效抑制芽孢杆菌属物种形成生物膜。环境离群菌株CR1可用于生物技术重要的单RL和PYO的工业生产。