Poplar Mushroom Production Of The Antimicrobial Substances

The anti-microbial experiment of 14 strains edible fungi showed that Agrocybe aegerita have great anti-microbial activity. The antibiotic produced by the fungus can effectively restrain the growth of bacteria yeast and mildew. Through anti-microbial experiment of 4 stains Agrocybe aegerita, it was found that they have different anti-microbial activity,so the best strain was decided to study. Through the submerged fermentation of Agrocybe aegerita, it was easy to grow and get many mycelia spheres which were even and dense. By the anti-microbial experiment of the fermented broth, it was found that the fermented broth showed great anti-microbial activity.Liquid culture experiments has confirmed that potato was the optimum carbon source and bran was the optimum nitrogen source.The optimum liquid medium selected with L16(45) test method contained 20% juice of potato, 6% juice of bran, 1.5% of sucrose, 0.05% of MgSO4.7H2O, 0.3% of KH2PO4. And the optional growth fermentation period, temperature, initial pH, liquid contents of the liquid medium in 500ml shake flask,rotate speed and quantity of inoculation were 8-10d. 26℃,pH 6.0-7.0, 140ml/500ml flask,150r/min and 10- 15%(v/v) respectively.At the same time, the effects of heat, pH , UV and proteinase on the stability of the bioactive substance in the fermented broth were studied. The water solubility and ion character of the antibiotics were analysized by pH paper chromatography and thin-layer chromatography. The results of early identification showed that the weakly-acidic antibiotics were stable to heat, pH and UV, and can be dissolved in water and some organic solvent. The physiological and biochemical characteristics of the high activity antibiotic substance were studied in orde to provide scientific basis for the further isolation and purification.The antibiotic substance was obtained from fermented broth by organic solvent extraction, treatment of active carbon adsorption, DEAE-Sepharose Fast Flow and Sephadex-G200 column chromatography. Through UV spectrum scan and HPLC,it was found that antibiotic substance was single purity and the most absorb apex of the antibiotic produced by Agrocybe aegetira nearby located 250nm.The activity ofantibiotic substance has consanguineous relationship with its structure,so the antibiotic substance was analysed by the infrared spectroscopy(IR) and nuclear magnetic resonance(NMR).In all, Agrocybe aegerita has delicious taste ,abundant nutrition and its metabolic substance was safe and innoxious. So the antibiotic substance producted by Agrocybe aegerita has important applied value,and will be hopeful empoldered a green native food preservative.