Enzymatic Properties And Intracellular Proteomic Analysis Of Irpex Lacteus Induced By Different Substrates

In this paper, the white-rot fungus(Irpex lacteus) is used as the materials, the fungal growth in PDA solid plate medium is investigated. The result shows that its growth characteristics is similar with the most other fungi, with slow start, then rapid exponential rise, finally flat growth. In different culture temperatures (23℃,28℃), its growth rate is clear different when the fungal growth at28℃is faster than that at23℃, indicating that the temperature of28℃is more suitable for the growth of the fungus. Using birch and spruce sawdust as the inducer and without inducer as the control, the lignocellulosic enzyme activity secreted by the fungus is detected. The result displays that the laccase activity is the highest among the ligninolytic enzymes, and the lignin-peroxidase activity is in the second, the manganese-peroxidase activity is the lowest. The lignocellulosic enzyme activity of Irpex lacteus induced by the sawdust is mostly higher than that of the control. There is significant difference between the teatment and control for the manganese-peroxidase and laccase activity. The exoglucanase activity is much higher than the endoglucanase activity in the cellulase. The exoglucanase activity is essentially increased along with incubation time, and the endoglucanase changes in up and down. The activity of both cellulase shows much high stability, with high expression level and no big changes affected by the culture time.The fungal intracellular proteome changes of Irpex lacteus induced by the sawdust of different tree species is detected by2-DE and tandem two-dimensional electrophoresis-mass spectrometry analysis.823protein spots are found in the control,673protein spots are detected in birch sawdust treatment and684protein spots are detected in spruce sawdust treatment. Compared with the control,32proteins with great differential expression in birch and spruce sawdust treatment are detected,10protein spots of which are up-regulated,22protein spots of which are down regulated. Each has3specific differential protein spots for birch and spruce sawdust treatment, respectively. The special differential proteins induced by birch sawdust are connected with membrane protein, membrane transportation and energy supply, and the special differential proteins induced by spruce sawdust are all connected with protein synthesis. There are3differential protein spots in much high homology with mammal proteins in all differential expression protein spots. There are5differential protein spots identified as the hypothetical proteins by mass spectrometry analysis, including No.675, No.506, No.508, No.228, and No.211, whose function are not yet clear, and maybe new proteins. The remaining22protein spots have different functional feature, including organic protein metabolism, ATP synthesis of proteins, material transport protein, respiration proteins, transcription&translation protein, protein energy metabolism, redox proteins, regulatory proteins and so on. In detection of intracellular proteome, we have not found the lignocellulose degrading enzymes, which also provides an evidence of those enzymes as the extracellular enzymes.