Study On White-rot Fungi Strains Screening And Optimizing The Liquid Fermentation To Produce Laccase

In this paper,we select six strains of laboratory existing white-rot fungi forscreening of liquid fermentation,filter out the good growth, high enzyme standard ofstrains.In shake flask culture medium of liquid fermentation to produce laccase andthe conditions of enzyme production optimization.And carried out the fermentationtank of laccase production expanding experiment, finally will be preliminaryseparation of laccase bacteria liquid. The study of the enzymatic activity and stabilityof laccase, get the following conclusion:1. In the process of6strains of white rot fungi strains liquid fermentation, theenzyme production peak appeared in7~11days. All of them can secrete lignindegradation enzyme system in the main three kinds of enzymes-manganeseperoxidase(Mnp), lignin peroxidase(Lip) and laccase(Lac). The growth ofPhanerochaete chrysosporium was most quickly and not easy to bacterialcontamination;Ganoderma lignin peroxidase (Lip) and laccase (Lac) ability issuperior to other strains. Phanerochaete chrysosporium and Ganoderma comparedwith other strains have stronger ability of lignin degradation.2. By Phanerochaete chrysosporium and Ganoderma liquid fermentation toproduce laccase condition analysis of single factor and orthogonal test, to study thedifferent culture medium and culture conditions on its laccase production.Determinethe Ganoderma,Phanerochaete chrysosporium, the optimal liquid medium flatleather bacteria (1L): Potato200g,20g of glucose,peptone4g,magnesium sulfate1.5g,VB10.1g, copper sulfate,0.5g,0.5g zinc sulfate, manganese sulfate2g, potassiumdihydrogen phosphate1.5g, tween-801g; The best culture conditions: fluid volume70mL, quantity of10%, fermentation temperature28℃, speed140RPM, mediuminitial pH of5. The optimized two strains of liquid fermentation to produce laccaseenzyme activity of Ganoderma20.354U/mL and Phanerochaete chrysosporium11.268U/mL.3. Through the laboratory small fermentation tank for Phanerochaete chrysosporium liquid fermentation to produce laccase expanding shake flasktest,using single factor and orthogonal test analysis Phanerochaete chrysosporiumoptimum conditions of laccase in fermentation tank:Temperature28℃, rotationalspeed300RPM, ventilation5L/min (ventilation than1.0VVM), medium initial pH5,15%inoculated quantity, get the most prolific enzyme level14.86U/mL.4. Using the method of salting-out,on fermentation tank of crude enzyme fluidhas carried on the preliminary separation of laccase, after freeze drying got crudeenzyme powder.Research the laccase produced by Phanerochaete chrysosporiumoptimum reaction pH and temperature was4.5and35℃; at pH6.5, the temperature is20℃enzyme liquid is kept stable.Crude enzyme powder is stable under the conditionof4℃refrigerated preservation.