Abstract: A cellulose-decomposing strain, named JJU-A, was isolated from straw turnover soil. According to morphological observation, biochemical testing and rDNA-ITS gene sequence, the strain JJU-A was identified as Irpex lacteus. A 3-month experiment was carried out with JJU-A inoculated on maize straw, and the decomposition rate and the function groups of the maize straw were determined after 30, 60 and 90 d. It was shown that the decomposition rate of cellulose, hemicelluloses and soluble saccharide was higher than that of lignin, as the decomposition rates of cellulose, hemicelluloses, soluble saccharide and lignin were 53.60% 58.89% 76.03% and 28.61%, respectively. Fourier infrared spectroscopy (FTIR) was used to detect the changes of function groups of maize straw. The relative absorption intensity of 1 046, 1 245, 1 335, 1 603, 2 900 and 3 383 cm^-1 decreased obviously, and the percentage of C=C, C=O, —CH₃, —CH decreased during the decomposition process, indicating that cellulose, hemicelluloses, saccharide and aliphatic compounds were degraded largely. In conclusion, the addition of Irpex laxteus JJU-A on maize straw could improve the degradation efficiency of straw and realize the resource utilization of straw.

Key words: infrared spectroscopy, decomposition process, maize straw, cellulose