The Preliminary Study Of An Antifungal Streptomyces Anandii And Its Metabolites With Antifungal Activity

In recent years, fungal diseases has threatened not only suffers′health and lives,but also the safety of animals and plants. The discovery and development of efficient,safe, low-toxic, broad-spectrum antifungal drugs have drawn public attention.Naturally, antifungal antibiotics are produced mainly by actinomycetes.This research was conducted to select antifungal actinomycetes from soils and studythe fermentation technology, the physicochemical properties, the separation andpurification techniques of antifungal antibiotics of the antagonistic actinomycete. Themain reserach findings of the study were as followed:(1)105actinomycetes were isolated by Pour Plate method from10soil samples.One strain designated JXNU02obtained by adopting combinatory approach ofconfrontation incubation and agar diffusion assay showed significant antifungalactivity. Based on morphological observation, cell wall components analysis,16SrRNA gene sequence analysis, cultural characteristics, physiological and biochemicalcharacteristics, the strain was identified as Streptomyces anandii JXNU02. Itsfermentation broth showed a broad-spectrum activity against all of the test strains,including filamentous fungi, yeast, Gram-positive bacterium and Gram-negativebacterium.(2) Single-factor experiments and orthogonal array designs were used to studythe medium composition and fermentation conditions. The optimum culture mediumwas consisted of soluble starch10g/L, soybean cake powder15g/L, KH2PO40.5g/Land MgSO4·7H2O0.1g/L. The optimized fermentation conditions were temperature30℃, initial pH value7.7, culture medium amount40mL/250mL flask, andfermentation time144h.(3) The research results of stability of the antifungal antibiotic from thefermentation broth of actinomycete JXNU02to heat, acid, alkali, protease andultraviolet radiation showed it had a stable activity to heat, acid and protease, butunstable to alkali and ultraviolet radiation.(4) The antifungal antibiotic from the fermentation broth of actinomyceteJXNU02were extracted with different solvents. The result showed thatwater-saturated butanol was the optimal extraction for bioactive component. Theantifungal substance from fermentation broth of strain JXNU02was isolated bymacroporous adsorbent resin HP-20，and then was extracted with water-saturatedbutanol, we got the crude extract. This study provides the solid foundation for the further research of antifungalantibiotic of Streptomyces anandii JXNU02.