Biodegradation of rice straw by a newly screened Aspergillus fumigatus XC6

Fifty strains from deadwood, rotted leaves, rice straw and wheat straw were tested for their ability to degrade rice straw, ten potential strains were further screened, and strain XC6 exhibited excellent ability in degrading rice straw. Identification of morphology and 18S rDNA gene sequences showed the strain was Aspergillus fumigatus. The process parameters for rice straw degradation by the strain were further studied. The initial pH and inoculation size were the most important factors affecting rice straw degradation, and an inoculation size of 10%, culture temperature 30 ℃, (NH4)2SO4 as nitrogen source, inoculation age of 36 h and initial pH of 4.0 were optimum for rice straw degradation by the strain XC6.  Under the optimal conditions, the rice straw degradation rate reached 100%±0.2%, and biomass was 22.9±1.1 g/L.