Screening Of Cellulose Degrading Microbe And Its Degradation Performance

In view of the problem that the straw is decomposed slowly under composting conditions and the compost time is long,the straw and soil are fully utilized to separate,screen and purify the indigenous high-efficiency cellulose-degrading microbe,and the self-selected high-efficiency cellulose-degrading microbe is the research object.The research on the compost effect in the process of composting corn stalks was carried out.mainly achieved the following results:The basal medium and Congo red-cellulosic sodium medium were used to separate the cellulose degrading microbe from the soil surface soil,low temperature compost samples,rice stalk rot,farm soil,fresh cattle and sheep feces,according to the hydrolysis circle and colony diameter.19 strains of cellulose-degrading microbe were obtained by preliminary screening(D/d?2.0);then the cellulase activity of filter paper in liquid culture environment was detected and compared,and the fungi with high cellulose degradation ability were screened.There are 2 strains of bacteria,the strain numbers are Z5-3,Z6-4,X11-1 and X3-5-1.The ratio of hydrolysis circle to colony diameter(D/d)of 4 strains is 2.76,3.63,4.51 and 2.11,cellulase activity was 0.68,0.77,0.45 U mL-1 and 0.50 U·mL-1,respectively,which was 5 to 8.5 times that of the control treatment.The morphological,physiological and biochemical properties and molecular identification of the selected cellulose-degrading microbe were determined.The cellulose-degrading microbe Z5-3 was Aspergillus flavus,and the Z6-4 was Trichoderma afroharzianum,X11-1 is Luteimonas sp.?and X3-5-1 is Pseudomonas stutzeri.Among them,Trichoderma harzianum has the function of straw degradation for the first time.The optimized enzyme production conditions were as follows:the optimal carbon source and nitrogen source of Z5-3 strain were glucose and sodium nitrate respectively,the initial pH was 7.0,the temperature was 30?,the carbon source and nitrogen source of Z6-4 were glucose and nitric acid,respectively.Ammonium,initial pH 7.0,temperature 35?;the best carbon and nitrogen sources for X11-1 and X3-5-1 are glucose and ammonium nitrate,initial pH 8.0 and 7.0,temperature 30? and 35?.The cellulose-degrading microbe added to the corn stalk entered the high-temperature period 2 days earlier than the non-microbe treatment,and the heating rate of the materials added to different strains was different.At the high peak temperature of the heap,the temperature of the bacteria treated by the compost was0.7?2.8? higher than that of the fungus,and the duration of the high temperature was extended by 2-3 d;the temperature of the X11-1 treated by the bacteria was 0.1?2.4? higher than that of the X3-5-1,Z6-4 treatment is 0.1?3.4? higher than Z5-3 treatment.The pH value of the added material has an increasing tendency compared with no bacteria,and reaches a maximum during the high temperature period.There was no significant difference between the two compost treatments,and there was a significant difference between the two microbe treatments.Among them,the treatment of fungi Z6-4,bacteria X11-1 and fungus Z5-3 was at a higher level,and the pH of Z6-4 treatment was the highest.The pH of the bacteria X3-5-1 treatment was similar to that of CK,which was significantly lower than that of Z6-4 and X11-1.The addition of cellulose-degrading microbe to corn stalk had no significant effect on the total salt content of the compost material.In the process of material compost.The cumulative release of ammonia and carbon dioxide peaks during the high temperature period,and the ammonia release rate is faster than carbon dioxide.Compared with CK,the addition of microbial agents has a difference in the loss of total carbon and total nitrogen.Adding cellulose degrading bacteria to compost,the carbon loss of composting materials has a tendency to decrease.The carbon loss range of the added bacteria treatment is 30.37%?34.89%,which is 0.77%?4.63%lower than CK,and the difference is not significant The nitrogen losses of Z5-5,Z6-5,X11-1 and X3-5-1 were 36.49%,34.19%,26.14%and 26.57%,respectively,which were 7.70%,10.00%,18.05%and 17.62%,respectively.,with significant differences.Bacteria work better than fungi in reducing nitrogen loss.In the high temperature period,the cellulase activity reaches the highest value,which is mainly caused by the degradation of bacteria;in the late stage of fermentation,it is mainly played by the fungus.The fungus which has a better degradation effect on cellulose is the Z6-4 strain,and the bacterium is a strain of X11-1.There were differences in the nutrient concentration of the materials treated with different strains.The content of phosphorus and potassium in the materials treated with Z6-4 was higher.The addition of different cellulose-degrading bacteria had different effects on the activities of urease,sucrase and catalase in the compost The urease and sucrase activities of the material treated with X11-1 were higher,which was significantly different from other treatments.The material added to the fungus Z6-4 had higher catalase activity;the addition of cellulose degrading bacteria had no significant effect on the material dehydrogenase.The first treatment to achieve maturity was the addition of X11-1,followed by the treatment of Z6-4,which was significantly different from other treatments.