Discovery And Analysis Of A Novel ?-glycosidase From Soil Microbes

In recent years,the development of new energy resources has been one of the main problems that social and scientific scholars concerning.Cellulose is one abundant renewable resource,and hydrolysis of cellulose to produce ethanol and other bio-energy has also been widely used in industry.At present,there are few enzymes with excellent enzymatic characteristics,and it is of great value to obtain new cellulase with good performance at stability,temperature resistance and activity.At the same time,cellulase shows excellent application ability in the food industry,agriculture and other fields.?-glucosidase acts at the last step of the hydrolysis of cellulose and control the hydrolysis rate.P-glucosidase is also widely used in food,medicine and agriculture industry,and its various aspects of performance make it a potential enzyme for industrial applications.The traditional method for sceening ?-glucosidase is based on pure strains.This method has its advantages,but also drawbacks.The development of bioinformatics technology and genome mining technology has lead to the discovery of plenty of new functional gene enzymes.The metagenomic method is collecting all the genomes of microbial colonies in an environment sample.It contains a large number of unculturable microbial genetic resources,which opens a new way to find new enzymes.And the function-driven screening method can quickly and intuitively screen the functional enzymes from the metagenomic library.In this study,the soil samples from the forest area of Yunnan,China were collected.At the same time,the genetic resources were enriched by the construction of the matagenomic Cosimds plasmid library.A new P-glucosidase gene,YNBG3,was obtained by screening the library with esculin-containing LB agar plates method.After a series of experiments,we know that the protein is a member of the third family of glycosidase,which has the conserved domain of the family.Polyacrylamide protein gel analysis showed that the molecular was weight of 84 kDa,which was consistent with the predicted molecular.The optimum temperature for YNBG3 was 53 °C,and the optimum pH was 5.2.When it was placed in the environment at 50 °C more than 12 hours,the enzyme activity still has more than 30%left.In addition,YNBG3 showed good tolerance to organic solvents.The activity of YNBG3 was enhanced in presence of EDTA and urea.These characteristics of YNBG3 make it a promising candidate for industrial applications,and provide some valuable reference for industrial applications of functional enzymes.