Pseudomonas Aeruginosa Bacteria Fermentation Production Of Rhamnolipid

The rhamnolopid, as one of important biosurfactant, has strong surface activity and emulsification capacity. It can be used in food, medicine, and petroleum, etc. Because it has strong anti-virus and anti-microorgnism effect, it can be used in active sludge treatment. The experiment of microbiol-synthetic biosurfactant started in 1970s. Microorganism can synthesize the surfactant, whose capacity is comparative to the chemical-synthetic, and it has strong biodegradability and can be used safely, so more and more attention was paid to it. It is nothing to say about it.Firstly the fermentation research of rhamnolopid was studied .we found that the production of rhamnolopid could reach 16.61 gram per liter when fed-batch carbon source in constant speed,which has big gap comparative to seventy to one hundred and twenty gram per liter in foreign patent .It indictates it has great potential to research, the second ,in the rhamnolopid fermentation ,we use waste oil,which conduce to reduce production cost and utilize waste oil.this has important significance.After fermentation, classical seperation method was used to obtain rhamnolopid. The result shows that most of the unwanted substances in the broth such as cells can be removed when centrifugated at 4000 rpm for 30 min. 5 g dry weight / L or 18 g wet weight / L cell can be obtained. Then chloroform : methanol (2:1) system was used to extract rhamnolopid. The extraction yield was about 80%. After extraction, rhamnolopid concentration was improved more than one time,from 1.76 gram rhamnolopid per liter to 2.86gram rhamnolopid per liter.The physical and chemical characteristics of rhamnolopid was studied and found its conductance curve have change twice,which coincides with the fact that rhamnolopid has two structures. The existence of ion concentration and surfactant has influence on critical micelle concentration. In solubilization experiment, the emulsification without surfactant was between 7 percent to 10 percent.however oil emulsification couldreach 12.5 percent in existence of rhamnolopid,which indicated rhamnolopid have emulsification. the best emulsification effect can be obtained when oil concentration was kept at 10%.