Optimization of Fermentation Conditions for Endophytic Actinomycete F03 from Houttuynia Cordata and Preliminary Study on Antibacterial Active Substances

F03is an Endophytic actinomycete with strong antibacterial activity,which was separated from Qinling Mountains wild Houttuynia cordataroot.Using S.aureus as an indicator bacterium,single factor experiment and orthogonal experiment were used to optimize the carbon source,nitrogen source of the medium and fermentation conditions.The antibacterial active substances of the fermentation broth was studied.The optimal culture medium was as follows:glucose 30 g,sucrose 10 g,soybean powder 10 g,peptone 10 g,K2HPO40.3g,NaCl 1g,CaCO32 g,distilled water 1 000 mL.The optimal fermentation conditions were as follows:initial pH value of fermentation broth 8,fermentation time 7d,fermentation temperature 28 ℃,shaking speed 140r·min-1,inoculum 7%.The antibacterial active substances had good thermal stability and acid-base stability.The results of paper chromatography of Doskochilova solvent systems showed the main antibacterical active substance to S.aureus was water-soluble metabolite.