Studies On The Biodegradation Of Some Mushroom Strains On The Straw

The biodegraded ability of 13 mushroom strains to straw was studied by the ways of mycology, edible fungi cultivated and analytical chemistry.In 13 strains, Pleurotus ostreatus (Jacq.:Fr.) Gray, P. cetriopileatus Sing., P. cornucopiae (Paul.: Pers.) Roll, Hericium erinaceus (Bull.) Pers., Hohenbuehelia serotina (Schran.:Fr) Sing., Agaricus bisporus(Lange)Sing., Agaricus blazei Murr. and Flammulina velutipes (Curt.:Fr) Sing.(white and yellow) are the strains that selective degrade lignin; Coprinus comatus (Murr.:Fr.) Gray, Pholiota mameko (T. Ito.) S. Ito et Imai and Pleurotus eryngii var. nebrodensis Inzenga are the strains that can selective degrade cellulose. Tricholama mongolicum Imai neither grew nor produced discolor zone.The difference of the degraded ability of strains to straw is evidence. In 13 strains, the degraded ability to lignin of Pleurotus ostreatus is the highest, the rate of lignin degradation is 17.86% after 15 days culture; that of Flammulina velutipes (white) is the lowest, lignin degraded rate is 2.30%. Pholiota mameko has the highest degraded ability to cellulose, after 15 days culture the rate of cellulose degradation is 17.32%; the cellulose degraded rate of Pleurotus ostreatus is 2.44%~the lowest one. The Select Factor (SF) of Pleurotus ostreatus is 9.79, the highest one in 13 strains, the others are all below 3. The correlation coefficient of d1/d2 and SF is -0.1476.The differences of biological efficiency among strains are very evidence that either cultivated with non-autoclaved material or cultivated with autoclaved sterilized (autoclaving) material. In the cultivation with non-autoclaved material, the rate of biological efficiency of Coprinus comatus is 234.96%, it's the highest one; that of Pleurotus ostreatus is lower, it's 136.98%. In the cultivation with autoclaved material, the rate of biological efficiency of Pleurotus ostreatus is 99.19%, it's the highest one; Flammulina velutipes (yellow) is the lowest, only 78.89%. The production cycle of Pleurotus ostreatus is shortest than the other either cultivated with non-autoclaved material or cultivated with autoclaved material. The strain P. cornucopiae is different, the cultivated ways influence its biological efficiency. The way of cultivated with autoclaved material is more suitable for P. cornucopiae.The rate of lignin degradation in the non-autoclaved straw which cultivated Pleurotus ostreatus is 50.24%. Compare to the other, the degraded ability of Pleurotusostreatus is the highest; the lowest one is P. cornucopiae, the degraded rate to lignin is only 11.66%. The result is as the same as that of the lignin degradation experiment, and it can prove indirectly that the lignin degradation experiment is accurate. It shows that culturing edible mushroom with straw is an effective way to degrade the lignin of straw.The result of the analysis to the degraded outcome of lignin by GC/MS and IR shows that in the selected 3 strains, the degraded ability of Pleurotus ostreatus is the highest than the other. In the GC/MS analysis, lots of compounds containing benzene ring are detected, it proved that lignin polymer is degraded during Pleurotus ostreatus cultured. The breakage firstly occur on the side chain and the bond between monomers, such as Ca-CB,B-O-4 etc., and form the monomers. Then Pleurotus ostreatus exhibits its special degraded mechanism, methoxy was displaced by methyl, then the ring-opening reaction was happened. This is different compare to the reported about the degradation mechanism of white-rot fungi. In IR analysis, the result is as the same as that of GC/MS. In the degraded outcome by Pleurotus ostreatus there are some special group such as guaiacyl and syringyl. The result proved that the lignin is degraded by Pleurotus ostreatus, and the first oxidation is on the side chain of monomer. Different from Pleurotus ostreatus, Coprinus comatus can't degrade lignin polymer completely, it can only breakage some bond between monomers in the lignin polymer. For the lack of sufficient data, the degradation mechanism of...