Quantitative Detection Of Biomolecule In The Fermentation Process By Surface-Enhanced Raman Scattering

Surface-enhanced Raman scattering technique(SERS),as the fingerprint spectrum,is commonly used to detect the structure of biomolecule.SERS techniques include the advantage and also overcome the defect of low signal strength of Raman spectra simultaneously.The microbiological fermentation is developing rapidly as the important technology of industry.Hence,SERS substrate was prepared to achieve the trace detection of fermentation process with its broad prospect in biological field.In this thesis,we designed the silver nanoparticles/Silicon nanowires array(Ag/SiNWA)substrate and the silver collosol substrate for SERS detection.There is abundant background noise in SERS detection for microbiological fermentation.Rolling Circle filtering method was adopted to eliminate the background noise with difference of the curvature radius of background noise and the biomolecule signal.The main contents of fermentation process studied are as follows:SERS detection of S-Adenosyl-L-Methionine(SAM)fermentation(aerobic type),1,3-ropanediol(1,3-PDO)fermentation(anaerobic type)and Lactic acid(Lac)fermentation(facultative anaerobic type).In the SERS detection of SAM,we established the linear relationship between the integrated intensity of peak and the SAM concentration.Compared with concentration measured by high performance liquid chromatography(HPLC),the Concentration of SAM in the real fermentation process was detected by the SERS with the relative error less than 13%,which showed the good performance in determination of fermentation process.In order to expand the application of SERS,we studied the 1,3-PDO fermentation process,with the glycerol(GLY)as raw material,1,3-PDO as product,and the Lac as by-product.As shown in the SERS spectra,the 1,3-PDO and Lac have individual Raman characteristic peaks,and the GLY has no individual Raman characteristic peak.We established the linear relationship of individual characteristic peaks for 1,3-PDO and Lac,and determined the concentration of GLY by difference of the common Raman peak at 2920 cm-1.The relative error was less than 20%,which showed thegood performance in fermentation process.Finally,the Lac fermentation process was studied with the GLY as supply and Lac as the product.We established the linear relationship between the integrated intensity of individual peaks and the concentration of Lac and GLY,which calculated by linear relationship in fermentation process was consistent with concentration measured by HPLC with the relative error less than 25%.Hence the above studies showed that SERS showed the good performance in the determination of industrial fermentation process,as the key point in next research.