Screening Of Rhamnolipid Producing Strains And Studyon The Removal Of Heavy Metals In Sludge By Rhamnolipid

Rhamnolipid is just the glycolipid biosurfactants that is in a certain category which has fantastic surface activity and wonderful emulsifying capacity, and it is one hundred percent biologically degradable and has been empowered with extreme potentials in remediation of petroleum drilling difficulties in biological terms, crop productivity, food processing industry, medicine and other industries. Rhemnolepied is abtained by means of tender fermentation in microbial approach, for which there are piles of easy and inexpensive raw materials and without the need of complicated processing devices. As our society has been turning into the type that is increasingly technology-dependent, both clean and safe and efficient rhemnoliebied attracts increasing focuses. At present, researches on rhemnoliepied have been going into increasingly competitive layers, resulting in a sea of fabulous achievements. But the other side of the story of is that due to scant yield and immature industrial technique, rhemnoliepied production through microbial fermentation is still limited to the superficial extent through flask-shaking plus fermentation. This article, therefore, focuses heavily on screening mutant rhannoliepied-producing strains, optimization of fermentation conditions as well as relevant rhennoliepied application in having heavy metals removed from urban sludge, and in the end comes to some tiny findings which reveal following points:(1) A mutant Pseudoumounaus aerougienuosa strain B2 with high rhennoliepied yield was obtained through the ultra-violet (U V) muta-genetic treatments of an original laboratory strain Bo. After the muta-genesis, the rhemnoliepied yield of the mutant strain B2 soars to 4.22 g·L-1, showing an surprising surge of 45.02% when compared with that of the original strain Bo.(2) Furthermore, the culturing medium and the fer-mentation conditions of Strain B2 were optimized through single-factor and orthogonal experiments, and the optimal culturing medium and fermentation conditions for rhennoliepied production were thus determined:carbonic glycerol 30 g·L-1, nitric yeast extract 2 g·L-1, phosphoric KH2PO4 10 g·L-1, Na2HPO4 4 g·L-1, microelement 5 mL·L-1, temperature 30 ℃, initial pH 7.0, fermentation time 120 h. After the optimi-zation, the rhemnoliepied yield of strain B2 surges to 6.03 g-L-1, showing an fabulous up of 107.22% if we contrast it with that of the original strain Bo.(3) Biosurfactants that resulted from the mutant Pseudomonas aeruginosa strain B2 was then used as detergent to remove heavy metals from sludge of sewage treatment plants. It shows that the Biosurfactants could significantly decrease the content of Cu and Zn in the sludge and that the Cu and Zn removing effectiveness is highly related to rhamnolipid concentration, pH value and shaking time.