Abstract: Lignin biodegradation plays an important role in biological disposition of agricultural wastes.Five strains of microorganisms were isolated from compost of agricultural and forestry wastes.They were identified to be Bacillus subtilis,Pseudomonas aeruginosa,Aspergillus niger,Penicillium simplicissim,and Streptomyces badius.These strains were proved to be capable of decomposing hydroxybenzene and nonhydroxybenzene lignin compounds of low molecular weight.To develop a high-efficiency of microbial inocula for composting,this research was designed to have a heap of natural rice straw inoculated with these strains of different ratios and composted for 30 days through solid-state fermentation.The strain mixture showed ligninolytic ability,which was further proved by analyses of enzyme production.Five different enzymes,lignin peroxidase,manganses peroxidase,laccase,cellulase and hemicellulase,were believed to be the most important catalysts in biodegrading process,and they always worked synergistically.When the ratio of bacteria∶actinomycete∶fungus was 85∶5∶10;Bacillus subtilis∶Pseudomonas aeruginosa,55∶25;and Aspergillus niger∶Penicillium simplicissim,2∶1,the degradation rate of lignin,cellulose and hemicellulose was the highest,being 22.13%,48.97% and 55.93%,respectively,after 30 days′ incubation.In rice straws without pre-sterilization,inoculation with the strain mixture of this ratio and fermentation for 30 days increased the degradation rate of lignin,cellulose and hemicellulose by 19.16,38.25,and 46.30 percent points,respectively,over the control,i.e.rice straws without inoculation.

Key words: microbial inocula, solid-state fermentation, enzyme, lignocellulose