Isolation And Characterization Of Thermophilic Cellulytic Microorganisms From Mushroom Compost And Study On Their Related Hydrolases

The contemporary relevance of biofuels as an attractive replacement for liquid fossil fuels has rekindled global interest in the conversion of lignocellulose biomass, which is the most amount of renewable sources of carbon and energy on our planet earth. This study focused on isolation and characterization cellulolytic microorganism from mushroom compost, the major results of the thesis are as follows:1. Thermophilic cellulolytic strains isolated from2samples of mushroom composts in liaocheng of Shandong province were analyzed by16SrDNA gene sequence. The strains B6、B60-1、B60-3were closely related to the genus Streptomyces in16S rDNA gene sequence, which were isolated from primary fermentation of mushroom compost, they screening extracellular xylanase. The strains Dl, D2.1, D2.2, D2.3, D3which were isolated from secondary fermentation of mushroom compost, were also closely related to the genus Streptomyces in16S rDNA gene sequence, they screening extracellular carboxymethyl cellulase (CMCase).2. Changes in straw composition during substrate preparation was determined, the lignin was almost not degraded, the content increased, while hemicellulose and cellulose content slightly decreased during the composting. Especially, the degradation of cellulose in primary fermentation was distinctly,40%to25%. The study of actinomyces diversity indicate that most of microorganisms from secondary fermentation of mushroom compost were uncultured microorganisms.3. The optimum temperature and optimum pH for carboxymethyl cellulase (CMCase) from the culture supernatant of strains D1, D2.1, D2.2, D2.3and D3were50-65℃Cand5.0, while for the xylanolytic enzyme from the culture supernatant of strains B6, B60-1, B60-3were70℃and6.0-9.0, respectively. Furthermore, B6, B60-1and B60-3retained about60%xyalanase activity after incubation at60℃for10h.4. The protein were separated by DEAE Sepharose Fast Flow chromatography, after SDS-PAGE electrophoresis analysis, the molecular weight of B6xylanase was estimated to be approximately45kDa. The enzyme was able to adsorption on insoluble xylan. The identifications by mass spectrometer presume this xylanase may be has not reported.5. We amplify the xylanases gene belonging to two major glycosyl hydrolase families (GH10and GH11) in strain B6genome by two degenerate primer sets. One distinct GH10and one GH11xylanase gene fragments were retrieved, and they both had90%identities with known sequences of Streptomyces. To understanding the xylanase from strain B6was becoming possible.