Studies On The Biodegration By Some Fungi To Straw

The biodegradations of nine fungi to straw were studied by methods of mycology, biochemistry and biotechnology. The strain which has high enzyme activity on selective degradating lignin of straw was screened. The cultural conditions for laccase producing were optimized. T-he laccase were isolated and purified, and the parts of dynamical character of laccase was measured.Capacity of producing lignocellulolytic enzyme by nine fungus was researched by methods of measuring color-zone or the diameter of mycelium and that of colored zone on PDA-Bav endamm, PDA-RB and color-zone trial which were showed in the characterization screening trial. The conclusion of the trial was that the capacity of producing lignocellulolytic enzymes i-ncluding laccase and peroxidase was strong and selective degradating lignin of straw by Phelli nus robustu. Coriolus versicolor and Trametes gallica. The highest ability of degradating lignin was Coriolus versicolor , of which the rate of Klason lignin degradation was 24.10% after 15 days culture, while Trametes gallica was the lower, lignin degraded rate was 20.09%. the highest degradated ability to cellulose was Phellinus robustus, after 15 days culture the rate of cellulose degradation was 25.62%;the cellulose degraded rate of Pleurotus ostreatus was 2. 23%--the lowest one. The Select Factor (SF) of Pleurotus ostreatus was 7.36, the highest one in 9 str ains. the Select Factor (SF) of Trametes gallica was 2.48^the lower one. Among the three fungus of biodegradation solid culture to straw during the 60 days, the degradation rate of lignin by Trametes gallica was highest (68.53%), while the degradation rate of cellulose by Coriolus rev sicolor was highest (78.42%);and selectivity coefficient by Trametes gallica was highest(0.27). while sele-ctivity coefficient by Coriolus versicolor was highest(0.78).The result by the liguid or solid media trial for the enzymes activities producing enzymes activity was showed that the high enzyme activity on selective degradating lignin of straw was Trametes gallica with highest enzymes activity of Lac, Mnp and Hcel. Trametes gallica had the strongest capacity of degradation lignocellulose in nature and producing laccase among the three fungus.The ptimum producing laccase culture which was researched was(g/L): carbon resource (saccharose 5). nitrogen resource (beef peptone 1), initial pH (4.0). revulsant(Tween8 0). We obtained also the best cultivation means was seed and fermentation liquid were grown by static means.The laccase was purified by embody (NH₄)₂SO₄ salting-out, dialyzing.then DEAE-Sepharo-se FF ion exchange chromatotography and then SephadexG-75 gel chromatotography. the results of purification multiple was 12.48 and the activity reclamation rate was 21.4%.The reaction process curve showed that this laccase accord the dynamical character of enzyme catalytic rea-ction. Following purification, the optimum reaction temperature of crude laccase was 40 degrees and the purified laccase was 30 degrees. The optimum reaction pH value of crude laccase w-as 5.0, while the purified lactase was 4.5. Important influence to laccase through metal ion involved that laccase activity were obvious promoted by sodium, bivalent zincum and cuprum ion. restrained the enzyme reaction by calcium in some extent, while restrained entirely laccase activity by bivalent iron ion. The Michaelis constant that laccase oxidize 2,2'-Azino-di-(3-ethyl-benzthiazoline-6-sulphonic acid)(ABTS) was 15. 47Mmol/L...