| In order to promote the decomposition of crop straw and return it to soil rapidly and solve the problems such as the waste of straw resources and pollution, we screened the bacterial or fungi with high-efficient degradation of straw lignocelluloses and studied its capability of degradating wheat straw. An isolate of filamentous fungus with higher cellulase activity and ability to decompose CMC and straw lignocellulose was screened from black soil samples taken from Heilongjiang province by using the soil dilution, plating and liquid culture methods. Morphological status on various media, and ITS rDNA sequences homology analysis were performed to identify the taxonomy of the isolate. The effects of different time, different N resources, different cellulose resources and different pH values on enzyme activities produced by fungus was analyzed, and The ability of wheat straw degradation of Y5 was determinated by using weight loss method and liquid culture. The fungus was identified as Penicillium ochrochloron and named Y5. Filter paper activity(FPA) and endo-1,4-β-D-glucanase(EG) were both reached the maximum after the first fourth day inoculated, averaged 53 IU/mL and 55 IU/mL, respectively, which were 22.6% and 18.2% higher than that of strain Trichoderma viride(AS3.3711), respectively. Enzyme activities were the highest under the condition of wheat straw used as C resources, which were 27.5% and 24.8% higher than that of AS3.3711. The FPA and EG activities were 35.7% and 14.9% higher than the AS3.3711 strain with NaNO3 as nitrogen source. The optimal pH value of liquid culture was 6. The cellulose, hemicellulose and lignin contents were degraded by 43.5%, 49.7% and 9.3% after the first 10 days inoculated, respectively, which indicated that Y5 had strong enzyme activities on degradation of cellulose and hemicelluloses of wheat straw. The Penicillium ochrochloron Y5 has strong ability of wheat straw cellulose degradation, and its cellulase activities are higher than some published researches. The Penicillium ochrochloron Y5 strain has the great potential in research and development for inoculant of crop straw decomposition. |
