Screening For Antimicrobial Endophytes And Optimization Of Its Ferment Factor

Endophytes are one kind of large, ubiquitous fungus group. Recent years, studies on Endophytes show that some antitumor and antibacterial products made by Endophytes. This allows applications of Endophytes enlarge more and more, and Endophytes become the one new hot point of medicine research.Based on searching for anti-Mycobacterium tuberculosis Endophytes, according to the principle of using much more Tested bacteria for searching active Endophytes, this study is extended to be as'Screening for antibacterial Endophytes'. Such the following items were carried through: plant sample surface sterilization, Endophytes isolation and purification, pretreatment for Endophytes fermentation products, screening for antibacterial Endophytes, identification and ferment optimization of active strain. The results obtained are following:1 Isolation and purification of Endophytes30 sorts of plant were dealt by the optimal surface sterilization method, and 46 strains were isolated. But 9 of them (3strains fungi, 6strains bacterium) can't be cultivated in vitro. And 7 of the left don't have fruiting body under our experimental condition.2 Screening for antibacterial Endophytes①the Endophytes fermentation pretreatment samples,37 acetone samples of hypha,37 ethyl acetate samples of hypha,and 37 fermentation broth samples dealt by ethanol deposition method were gotten.②Using the double dilution method (Rhodes incline solid medium) to deal with 111 samples, the anti-Mycobacterium tuberculosis Endophyts are obtained that are Strain EP-S23 deriving from Phytolacca acinosa, Strain EM-L40 deriving from Mahonia fortunei, and Strain EC-S44 deriving from Cinnamomum camphora (Linn.) Presl, which can inhibit the growth of Mycobacterium tuberculosis standard strain (H37Rv) with the fermentation compound density of the 10mg/ml. And strain EC-S44 deriving from Cinnamomum camphora (Linn.) Presl with the fermentation compound density of the 15mg/ml can inhibit the growth of Mycobacterium tuberculosis drug-resistance strain.③Using the Agar dilution method to screen the former three active Endophytes again, the extraction compound solution of Cinnamomum camphora (Linn.) Presl strain EC-S44 can inhibit 5 Tested pathogens with different density, and the inhibition zone of active strain EC-S44 against Staphylococcus aureus (ATCC 25923) is 16mm, and MICs is 6.5mg/ml.3 Identification and ferment optimization of active strain①Active Strain EC-S44 is identified by morphology as the one of Fusarium, named as Fusarium sp. Strain EC-S44.②The optimum ferment condition of Fusarium sp. strain EC-S44 is: PDA (3% glucose, 0.3% beef extract), 4% fermentation inoculation amount, 8.0 initial pH,26℃, 150rpm.Under this condition, for Fusarium sp. strain EC-S44, the capability of anti- Mycobacterium tuberculosis drug-resistance strain enhances, and the MICs is 12.5 mg/ml.