Screening Of Strains That Efficiently Decompose Cellulose And Lignin And Their Role In The Utilization Of Crop Straw Resources

Cellulose and lignin are the main components of crop stalks,contain a large amount of carbon and nitrogen elements,and have high resource utilization value.Among the many straw degradation technologies,the microbial agent degradation method has been widely concerned by researchers at home and abroad for a long time because of its low cost,environmental protection,strong adaptability to temperature and pH changes,but there are also High,long degradation cycle and other shortcomings.In this study,strains with the ability to efficiently degrade cellulose and lignin were screened,their growth characteristics were analyzed,and the characteristics of enzyme production were studied.On this basis,microbial inoculants were prepared to study the effects of inoculants on the composting effect and in composting The change rule of fertilizer efficiency index.Provide an efficient and economical microorganism treatment method for straw degradation applications.The research results are as follows:1.After separation and screening,5 cellulose-degrading strains were obtained this time:X2,X4,X5,X7,X12,Physiological and biochemical tests were carried out on the strains,and after 16S rDNA molecular biological identification,they were Bacillus(MN251922),Bacillus ginsengisoli(MN251923),Bacillus megaterium(MN251924),Bacillus aryabhattai(MN251927),Klebsiella(MN251928),2 strains degraded Strains:Q2 and Q8,identified as Bacterium(MN251929)and Klebsiella pneumoniae(MN251931),respectively.2.Analyze the growth characteristics of 7 strains.Among them,the best growth conditions of the five cellulose-degrading strains were 37?,pH value 7;the cellulase activity of X5 and X7 strains started to reach a stable peak at 24h,and the cellulase activity of X2,X4 and X12 strains was at 48h After reaching the peak.The optimal growth conditions for the two lignin-degrading strains Q2 and Q8 were 37? and pH7;the laccase activity of the Q2 strain peaked at 36h,and the laccase activity of the Q8strain peaked at 48h.3.Study the influencing factors of strain enzyme activity.Among the five cellulose-degrading strains,X2,X4,X5,and X7 strains had the best pH value of 7 for enzymatic hydrolysis,and X12 had the best pH value of 5 for enzymatic hydrolysis.A comparison showed that the addition of enzyme-induced wheat bran 3g/L to X4,Cellulase activity of X7 and X12 were increased by 5%,13%and 15%respectively;2strains of degrading lignin strains Q2 and Q8 had an optimal pH value of 3,and wheat bran 3g/L added to Q2 and wheat bran 5g/L increased the activity of Q8 laccase by18%and 38%.The cultivation of high-efficiency strains under optimal conditions resulted in cellulase activities reaching 11.03U/m L,11.51U/m L,9.71U/m L,8.62U/m L,6.11U/m L,and laccase activities reaching 796U/m L,respectively.,662U/m L.4.Mix bacterial solution with zeolite to prepare compound bacterial agent.According to calculation,the number of bacteria contained in 1g of attachment carrier can reach 3×10¹⁰,and the rate of infectious bacteria is below 20%.The straw degradation rate can reach 39.99%in the 14-day inoculation of self-sieve high-efficiency strains through the initial straw degradation experiment,and the addition of certain nutrients at the beginning of the reaction is beneficial to the improvement of straw degradation rate.5.Self-made four kinds of microbial inoculant products according to the proportion of different bacteria.Inoculation of compound bacteria on compost fermentation,compared with the blank and commercially available bacteria agents,various water quality indicators of the experimental group inoculated with compound bacteria were improved,and the inoculation of compound bacteria had a certain effect in removing the odor.The study found that the inoculation effect of the self-made product No.4 compost was the most obvious.After 21 days of compost fermentation,the maximum temperature of the compost was increased,and the duration of high temperature was extended.Compared with the blank group,the total nitrogen consumption was reduced by 13.9%,and the ammonia nitrogen consumption was reduced by 31.2%.TOC fell by 71%,and the C/N was:14.8.The nitrate content is increased to 2.71g/kg.The content of dissolved total phosphorus showed a trend of increasing first,then decreasing,and finally tending to be stable.6.The study found that the seed germination rate of the inoculated No.4 product inoculum reached more than 80%in 15 days,that is,it reached the standard of composting harmless rot.Compared with the blank and commercially available inoculants,the composting cycle was shortened.After 21 days of fermentation,the total number of colonies remained relatively stable at 10⁹/g.From the 3rd day to the 9th day of fermentation,the removal rate of fecal E.coli decreased rapidly,reaching 66.7%,which had a good inhibitory effect on fecal E.coli in compost fermentation.