Screening And Fermentation Of Microbial Strains Producing β-carotene

In this report, several bacteriums trains that producing carotenoids were isolated from oilsoil polluted by oil. One bacterium strain that produces more β-carotene was identified andclassified as Blakeslea trispora through morphologic and biochemical experiments.We gotthe best craft conditions for producing β-carotene industrially by Blakeslea trispora. This craftincludes fermentation and extraction craft conditions.Considering some nutritional factors such as carbon-source, nitrogen–source, andfermentation promoter such as vegetable oil, surfactant, oxidant and an optimum medium ofBlakeslea trispora for flask fermentation was obtained. The results are as follows, solublestarch4%, conr steep liquor3%, vegetable oil4%，MgSO₄0.03%，Tween800.8%，H₂O₂30μmol·L^-1.Using saponification method to purify before extracting. The optimum saponificationconditions of purification were studied by the orthogonal test design.The optimum purification condition were as the following: NaOH0.5mol·mL^-1, ratio of acetone and petroleumether1:8（g: mL）, saponified temperature is35℃, saponified time is45min. Alkalinesaponification can remove the glyceride and fatty acid. The results showed that theinfluencing sequence of different factors on extraction was as follows: that saponifiedtemperature, the added NaOH and saponified time.The extracting β-carotene from Blakeslea trispora using ultrasonic method was studiedto get the best craft condition. The optimum ultrasonic extracting conditions of β-carotenefrom Blakeslea trispora were studied by the orthogonal test design. The optimum conditionswere that extaction solvent: Ethyi acetate, ultrasonic power:100W, extraction temperature35℃, extraction time:45min.As antioxidants,Ve and Vc-cetylate could protect β-carotenefrom oxidation and enhance the β-carotene production by4.2%. times of extraction:3.Theyield of the extracted β-carotene achieved92.2%.