Screening, Identification and Fermentation Process Optimization of a Wild Fungus Against Pathogens

Abstract

To obtain wild mushrooms having broad-spectrum antimicrobial activity and enhance the antimicrobial compounds productivity were our purpose. The active strains were screened in terms of the methods of well diffusion assay and hypha growth rate. the fermentation parameters for antimicrobial compounds productivity were optimized by response surface analysis and orthogonal test. One white-rot fungus 0331 with broad-spectrum antagonistic to pathogens was obtained,and it was identified as Cerrena sp. by ITS-5. 8 rDNA sequences analysis. The fermentation broth showed the antimicrobial activity against Staphylococcus aureus, Escherichia coli,Monilia albican,Bacillus subtilis and Rhizoctnia solani. The optimal medium for 0331 was composed of(in g / L) : potatoes 13. 99,wheat bran 7. 00,Sucrose 41. 58,KH 2 PO 4 2. 00,MgSO 4 ·7H 2 O 2. 00,VB1 0. 027. The optimal culture conditions were as follows: the initial pH value of medium 5. 0,the fermentation period 10 d,packing volume 110ml /250ml,inoculation 8mL /100ml,rotate speed 180r / min, temperature 28℃,respectively. The 0331 strain showed obvious antimicrobial activity,with an increase of 30. 37% compared to the original fermentation parameters.