| Nature sewage pollution mainly comes from straw leaves,treatment often can only rely on fishing,such a waste of time.Cellulose is an important renewable resource.There are many ways to degrade cellulose,but the microbial degradation is the most effective and environmentally friendly way.It was discovered that a variety of microorganisms can produce cellulose enzyme,but truly,there are few effective enzyme production strains and and performance is not stab le enough.Nowadays,as people's living standard,the growth of population and the acceleration of industrialization and so on,the cause of global energy demand is constantly raised.As a result,the problems caused by,for instance,global warming,oil co nsumption and energy security,etc.,are pushing people various to make efforts in such aspects as speed up instead of energy research.C urrently,this area for biofuels,the development of cellulosic ethanol research and utilization has become the research focus in the scientific research workers,in the nature of biological resources,cellulose,is generally thought to compare cheap and one of the largest and most abundant resources,it is mainly made up of three kinds of ingredients such as cellulose.The objective of this project is to screen out strains with high ability of degrading cellulose from wastewater.First,we identified the type of strains,and then studied the characteristics of the enzyme production by them.The main results are as follows:(1)Strains with different degradability were screened from the ditch,paper mill and livestock farm arround Qufu Normal University.The initial screenings were determined Hutchison Fluid Medium and grouped them according to their degradability.We have screened ten strains with larger transparent circles(>1.00 cm)by using Congo red medium,five strains(>2.00 cm)were chosen to determine their enzyme activity.Further study shows that T33 strain(Delftia lacustris)and X31 strain(Streptomyces phosalacineus)are more effective than others.(2)Through the further determination,the logarithmic growth p hase of T33 strain is the forty hour and X31's logarithmic growth phase is the fourth day;we can conclude that these two strains to degrade cellulose are not by secreting endoenzyme.The optimal carbon source of 2 strains is sodium carboxymethyl cellulose,the best nitrogen source is yeast powder;p H,temperature,speed,and the range of sodium carboxymethyl cellulose was determined by single factor optimization.Using Central Composite Design with response surface method,exploring the optimal enzyme production conditions of T33 strain and X31 strain.T33: carbon source is sodium carboxymethyl cellulose,the nitrogen source is yeast powder,p H is 6.50,the concentration of carbon source is 9.10 g/L,the temperature is 28.00 ?and the rotational speed is 160.00 r/min;X31 : carbon source is sodium carboxymethyl cellulose,the nitrogen source is yeast powder,p H is 7.00,the concentration of carbon source is 10.30 g/L,temperature is 30.00 ?,rotational speed is 170.00 r /min.(3)By cellulose Congo red test and enzyme activity test,make sure 2 strains of bacteria have the ability to degrade cellulose.The results of T33 are as follows: the filter paper enzyme activity of optimized is 1.95 U/m L,than before(1.26 U/m L)increased by 54.76%;The results of X31 are as follows: the filter paper enzyme activity of optimized strains is 2.25 U/m L,than before(1.40 U/m L)increased by 60.71%.(4)Ultimately,We optimized the culture conditions and made some simple application experiment,and determined that T33 and X31 strain all had the ability to degrade paper and corn stover. |
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