Optimization Of The Solid-state Fermentation Conditions For Manganese Peroxidase Of The White-rot Schizophyllum Sp. F17, And Scale Up The Enzyme

Manganese peroxidase (MnP) secreted by white-rot fungus is the main component of the lignin-degrading enzyme system, it plays an important role in depolymerization of lignin, decolorization of pulp and dye. This study utilized a local white-rot fungus (Schizophyllum sp.F17) to produce MnP, then the solid-state fermentation conditions for MnP of the white-rot Schizophyllum sp. F17 was studied, on this basis, designed a tray bioreactor with ventilation to scale up MnP, and carried out a preliminary study of fermentation kinetics in the bioreactor.1,This study choosed a mixed solid nutritional media which included pine sawdust, straw and soybean powder from rice hulls, pine sawdust, wheat bran, rice straw, wheat straw and soybean powder by response surface method, and the best ratio of the three components are:0.52:0.15:0.33, then the maximum enzyme activity was 11.18 U/g in the first 6 days of fermentation with the mixed solid nutritional media.2,Carried out optimization of solid state fermentation conditions for MnP of the white-rot Schizophyllum sp. F17. In the single factor experiment, the best solid-state fermentation conditions for the MnP were that inoculation amount 1 mL/g, loadage 15 g, temperature 30℃, moisture 0.5 mL/g, but got a different solid-state fermentation combination condition by response surface method, that was inoculation amount 0.5 mL/g, loadage 10 g, temperature 25℃, moisture 1.0 mL/g. The results showed that inoculum amount, loadage, temperature, moisture had a significant impact on production of the MnP, and also there was a great interaction between the factors, MnP activity was 11.18 U/g before the optimization, but it increased to 12.83 U/g after the optimization.3,Added inducer while carried out producing MnP by solid-state fermentation, results showed that studied inducer included aromatic compounds, surface active agents and so on, which all was effect to produce MnP. In these inducers, there was the most obvious effect while added 0.1 g/L veratryl alcohol,0.2 g/L Tween 80,0.1 g/Lβ-cyclodextrin and 0.5 g/L starch, the MnP activity were raised respectively 10.38%,10.23%,10.96% and 10.18% before added induce. Got a mixture induce composed of Tween 80, veratryl alcohol, starch andβ-cyclodextrin, the four concentrations were 0.1 g/L,0.0196 g/L,1.0 g/L and 0.01 g/L, and the MnP activity was 14.37 U/g while added the mixture inducers, the data increased 11.75% compared with not added inducer.4,According to the characteristics of Schizophyllum sp. F17 by solid-state fermentation, and combined with the advantages of packed bed reactor and the tray reactor, designed a tray bioreactor with ventilation to scale up MnP. Volume of the glass reactor is 5 L, it is 10 times the size of the 500 mL flask, and it has the advantages of good ventilation and heat dissipation, the reactor can achieve the purpose of scaling up MnP.5,In self-designed tray bioreactor with ventilation, Schizophyllum sp. F17 producted manganese peroxidase by solid-state fermentation with mixed nutrient medium, which included pine sawdust, straw and soybean powder. At the 96th hour of the fermentation time, the maximum enzyme activity reached 13.51 U/g. Positive correlation is shown between mycelial growth and the manganese peroxidase production. The release rate of carbon dioxide can be used as an index of forecasting mycelial growth. The kinetic models of solid-state fermentation for mycelial growth, the manganese peroxidase production and the release rate of carbon dioxide were developed based on the experimental results, and the model parameters were fitted. To some extent, these models can be used to analyze the production process of manganese peroxidase by solid-state fermentation.