Monorhamnolipid production strain and application thereof

Abstract

The invention discloses a monorhamnolipid production strain and an application thereof, and belongs to the technical field of biology. The pseudomonas aeruginosa PAO1 strain is used as an original strain, the rhlC gene of the pseudomonas aeruginosa PAO1 strain is replaced with an rhlAB-R gene cluster through a homologous recombination method, and the pseudomonas aeruginosa strain capable of specifically producing monorhamnolipid is obtained. The random mutation is further combined, and a mutant strain with the single rhamnolipid production level remarkably improved is screened out. According to the mutant strain, commercially available goldfish sunflower seed oil is used as a substrate, fermentation is carried out in a 5L bioreactor at 37 DEG C for 90 hours, the concentration of monorhamnolipid reaches 62.7 g / L, the purity reaches 95.16%, and the ratio of Rha-C10-C10 is the maximum and accounts for 68.59%.

Description

【Technical field】 [0001] The invention belongs to the field of biotechnology. 【Background technique】 [0002] Rhamnolipids are a class of surface active molecules secreted by Pseudomonas aeruginosa or Burkholderia and belong to biosurfactants. It has the characteristics of biodegradable, low toxicity, and effective in extreme environments. In addition, it also has the ability to inhibit microorganisms, skin compatibility and chelate heavy metal ions to deal with heavy metal pollution, and promote the dissolution and biodegradation of slightly soluble organic compounds. These characteristics of rhamnolipids make it widely used in fields such as biological control, cosmetics, medicine, detergent, environmental cleaning and mining. [0003] The commonly referred to as "rhamnolipid" is not a single structure, but a mixture of many homologous structures. Up to 28 rhamnolipid structures with different structures have been found in known reports. It has the basic characteristics...

AI Technical Summary

Problems solved by technology

However, the chemical synthesis process is complex and the cost remains high

[0005] Although as early as 1980, researchers isolated a strain of Pseudomonas aeruginosa ATCC 9027 (DSM 1128) from patients with external ear infections, which can specifically produce mono-rhamnolipids, but at 37°C, its The level of monorhamnolipid produced is much lower than that of Pseudomonas aeruginosa PAO1 strain (Complete genome sequence of Pseudomonasaeruginosa PAO1, an opportunistic pathogen. Nature 2000,406:959-964.); The personnel verified that the ATCC9027 strain does not have infectivity, but at 30°C, the level of pyocyanin produced by the ATCC9027 strain is much higher than that of the PAO1 strain, which is still a problem that cannot be ignored; these problems greatly limit the development of the ATCC9027 strain. Application (María-Victoria Grosso-Becerra et al., Pseudomonasaeruginosa ATCC 9027is a non-virulent strain suitable for mono-rhamnolipidsproduction)

[0006] In addition, some researchers have tried to express the gene cluster related to the synthesis of single rhamnolipids in the genome of Pseudomonas aeruginosa in heterologous hosts such as Escherichia coli or Pseudomonas putida to achieve the production of rhamnolipids, but the yield is far from Much lower than the level of rhamnolipids produced by Pseudomonas aeruginosa itself (references: Cabrera- Valladares N, Richardson A P, Olvera C, et al. Monorhamnolipids and 3-(3-hydroxyalkanoyloxy)alkanoic acids (HAAs) production using Escherichia coli as a heterologous host[J].Applied Microbiology and Biotechnology,2006,73(1):187-194.Wittgens A,TisoT,Arndt T T,et al.Growth independent rhamnolipid production from glucoseusing the non-pathogenic Pseudomonas putida KT2440[J].Microbial Cell Factories,2011,10(1):80.)

Images