Screening And Identification Of Lignin Degrading Fungi And Related Enzymes Activities Research

Lignin is a natural macromolecule polymer, which has high molecular. It is composed of coniferyl alcohol, sweet beans, mustard seed alcohol units, such as aromatic structures and so on. It is stable in nature. A number of lignin in the natural environment course environmental pollution and resources waste. With the understanding of human beings on the environment pollution and resource crisis deepening, more and more attention has been paid on natural macromolecule renewable and biodegradable materials. In nature, the lignin has huge reserves and its content produce150billion tons by every year second only to cellulose. Studies have shown that, Lignin and cellulose often exist together, the degradation of lignin affected the degradation of cellulose. So the degradation of lignin is the key step of natural polymer materials circulation in the nature. Microbial action is main process to degrade of lignin, among them fungus have good effect on the degradation of lignin。It has been known that part wood rotting edible fungi can use the timber to grow and have good ability to degrade lignin. Therefore, this thesis used wood rot fungi as the research object, the activity of enzyme, production optimized conditions of enzyme were studied, the strain compared mixed enzyme production and practical application were identified. The main results as follows:1. Though the test of the guaiacol, compared the fungi included J101, J201, J301, J401and J501, which isolated from the soil and grown faster than other edible fungi. The study showed that Thai Ganoderma lucidum, J201, Black Auricularia auricular and Griflola frondosa have high activities of lignin degradation. The circle diameters of degradation were40.0mm,46.7mm,42.0mm and39.7mm, respectively. It is significantly greater than other strains (p=0.05).2. Studied the lignin degradation enzyme production capacities of Thai Ganoderma lucidum, J201, Black Auricularia auricular and Griflola frondosa. The results showed that the lignin peroxidase actives were121.8U,144.9U,112.3U and145.9U, respectively; the manganese peroxidase actives were109.9U,142.9U,112.3U and136.6U, respectively; the laccase peroxidase actives were520.1U,2065.3U,527.3U and205.7U, respectively. Optimized lignin degrading enzyme production conditions of4kinds of fungi. Thai Ganoderma lucidum, J201and Black Auricularia auricular had the similar lignin degrading enzymes optimum conditions. The lignin degradation enzyme production best time is at9-12days, optimum temperature was30℃, optimal pH value is between6and7, best ratio of carbon nitrogen ratio for15to20. Griflola frondosa produced lignin degradation enzyme of the best time is6to9days, optimum temperature is30℃, optimal pH value is6to7, best ratio of carbon nitrogen ratio for15to20.3. Through the observation found that the morphology of the J201was hyphae white, villous, across and branches, had a lock joint; colony forming a cone, edge was not neat, the color of back was yellow; spore was cylinder, smooth and colorless. The molecular biology identification showed that18sRNA PCR amplified fragments of J201was about700bp. Based on ITS sequence homology comparison found that J201was similar to Trametes versicolorBAFC285. Comprehensive the above characteristics, predicated J201was Polyporales, Polystictus, sp.4. The enzyme production of different mixed with Thai Ganoderma lucidum, J201and Black Auricularia auricular study showed that lignin peroxidase from big to small were J201, Thai Ganoderma lucidum, Black Auricularia auricular,(Thai Ganoderma lucidum and J201),(J201and Black Auricularia auricular),(Thai Ganoderma lucidum, J201and Black Auricularia auricular),(Thai Ganoderma lucidum and Black Auricularia auricular), significant difference (p=0.05). Manganese peroxidase and laccase peroxidase were similar with lignin peroxidase, so mixed treatment could not improve the lignin degrading enzymes ability of strain.5. Complete actual measurement of lignin degradation after vaccinated the4strains into rice husk. The4kinds of fungi strains all have ability to depredate rice husk lignin. At56days the degradation rates were respectively34.7%,21.6%,17.8%and14.3%, significant difference (p=0.05).