Study On Diversity Of Cellulose-decompsing In Soil Of Eastern Qilian Mountains And Its Degradation Characteristics

Cellulose is the most abundant renewable organic molecules, belonging to thenumber of the most massive energy renewable resources. However,cellulose,hemicellulose and lignin are often difficult to degrade in natural conditions.Means the use of physical and chemical cellulosic substances into energy andproducts,while higher costs and great waste of resources. Microbial degradation ofcellulose is the best way to efficiently complete the transformation.Due to the special geographical location, affected by different climate, Gold RiverEasten Qilian forming a unique biological structure.It is the important areas for thebiodiversity research and the biological gene bank. The test plate dilution culturemethod and the use of ITS rDNA sequence analysis tools to study the geographicalcellulolytic fungi in soil type, quantity, such as the composition and phylogeny revealsgrassland soil environment in the region cellulolytic fungi communities essentialcharacteristics, distribution conditions and enzyme production capability. The resultswere as follows:1, Under different separation conditions, the decomposition of cellulose isolateddifferent fungi, the optimum conditions for the separation of cellulose-decomposingfungi in soil: the optimum temperature25℃, the optimum pH was6.5. The numberof colonies cellulolytic fungi bengal agar medium separation obtained dominant,isolated cellulose filter media law decomposition fungi least. Different media andseparating the cellulose obtained by the decomposition method of the type andnumber of different fungi, there are some differences.2,35kinds of fungi by phenotypic identification systems and ITS rDNAsequences phylogenetic analysis. The results were as follows:35strains of variousshapes on PDA; combined with ITS rDNA phylogenetic analysis, initially identified35fungi belonging to: Trichoderma spp.,Mortierella spp., Penicillium spp., Mucorspp.Fusarium spp.,Hypocrea spp.,Aspergillus spp.3, Three fungi have a strong ability to decompose cellulose, and conducted apreliminary study on the growth conditions, the results showed that: the optimumtemperature range for the three fungi between25to30; optimum growth pH due todifferent species lie between5to8; optimum growth concentration4%to5%. StrainXJ-4has a better degradation characteristics, the highest of its ability to degrade cellulose Chinese fescue, the strain was cultured15d, Chinese fescue weight loss ratereached55.4%, the decomposition effect is obvious.4, Through single factor experiments to optimize the strain XJ-4cellulaseproduced by liquid fermentation medium formulations and culture conditions: the bestcarbon source for the corncob powder, added in an amount of5%; optimum nitrogensource was soybean meal, added in an amount of0.42%; liquid medium withphosphate buffer to adjust the initial pH was8.0, a salt concentration of between2.0%to3.0%, the liquid volume of the fermentation medium50mL/250mL, then shaker at20℃,160r/min,5d.