Cyanobacteria Baicalin Biological Conversion Preliminary Study

This issue is about the biotransformation of Baicalin by microalgae systems,to investigate the possibility that the microalgae system can be a kind of biotransformation system or not,to research its biotransformation characteristics and its biotransformation capacity.Also,we can find another way to change the structure of Baicalin and improve its activity.First of all,it is necessary to establish a stable culturing system for PCC7002 Cyanobacteria,including separation and purification of cyanobacteria,prescription of MA medium liquid and solid cultivation of algae species,preservation,determination of the growth curve and so on.Synechococcus.sp.PCC7002 can grow up under the following conditions:pH between 5 and 7.5;temperature between 30℃and 35℃;the shaking speed is 120rpm,but pH 5,temperature 35℃,speed 120rpm are the best conditions for growing up.It takes PCC7002 about two weeks to grow up from OD₇₀₀ 0.3 to 0.8.In the study of Baicalin's stability in the medium,we mainly research the pH and temperature factors on the effects of Baicalin.From the pictures and TLC results we know the Baicalin can grow up in a steady state when pH is between 4.5 to 5.5,but the content reduces when pH is 6.8.The temperature factor has little effect on Baicalin's stability.35℃is the best growth temperature for PCC7002,and at this time Baicalin can always exist.So the conditions for the biotransformation by PCC7002 are:MA medium, 35℃,pH 5.5,120rpm,Baicalin concentration 0.1mg/ml,reaction time,3 days;the conditions for the biotransformation by PCC7002 are:BG11 medium,30℃,pH 5.5,120rpm,Baicalin concentration 0.1mg/ml,reaction time:3 days.Through the selection of systems,PCC7002 and PCC6803 could impact the structure of Baicalin,but PCC7120 could do nothing.We established the TLC and HPLC methods for the products.The developing agent consisted of ethyl acetate-butanone-formic acid-methanol(10:7:0.5:1).Condition of HPLC:The mobile phases consisted of methanol-water-phosphonic acid(47:53:0.2); The UV detector at 280 nm;Speed,1ml/min;Column temperature,40℃.From the result of TLC and HPLC,new component occurred after biotransformation by 7002, and the polarity of the product was increased;but no component occurred after biotransformation by 6803,and Baicalin disappeared.Maybe PCC6803 could make the disintegration of Baicalin happened.So the experiments determined the feasibility that the algae system could be a new kind system of biotransformation.