一株产表面活性剂菌株的筛选、培养条件优化及产物性质OACSTPCD

A bacterium capable of producing surfactant was screened from the sediment of sewage plant in the western suburb of Changchun.The colony of the strain is small and milky white.The individual shape is round under the microscope,and is gram-negative.The results of 16S rDNA sequence showed that the strain belonged to Pseudomonas sp.and was 100％similar to Pseudomonas libanensis(KT767978),was named Pseudomonas libanensis PbA.Product of 0.54 g/L could be synthesized by culturing the strain using glucose as carbon source and KNO3 as nitrogen source with the inoculation amount was 5％mass fraction at 27 ℃,pH 7 and cultured for 3 days.Analysis results showed that the synthetic product from the strain was glycolipid anionic surfactant by charged result,TLC analysis,and sugar content determination.The emulsification index and the diameter of oil drain ring of the surfactant with a concentration of 0.04 mg/mL was 60.3％and 5.6 cm,respectively.The surface tension of the surfactant decreased from 65.3 mN/mi(concentration 0.4 g/L)to 54.1 mN/m(concentration＞106 mg/L)with the increase of concentration,and the critical micelle concentration(CMC)was 106 mg/L.The basic data are provided for enriching the surfactant praducing bacteria,opening the fermentation production process and the application of surfactants.