Biodegradation Of PET And TA Based On Whole-cell Catalysis

As an important branch of industrial biotechnology,whole-cell biocatalysis has been applied not only to food,chemical,pharmaceutical,new energy and other fields.The in-depth development and application of biotechnology have shown unique advantages in solving environmental pollution.PET fibers pose a certain threat to the environment from processing,use,and disposal.Improving the biodegradation efficiency of PET and solving the pollution problems of PET fiber processing wastewater cannot be ignored.In this project,a whole-cell catalyzed PET biodegradation system was constructed,in which a strain using PET as the sole carbon source was used as a whole-cell biocatalyst,and enzyme activators(Ca²⁺?Mg²⁺)and biosurfactants(Rhamnolipid?Sophorolipid)were synergistic substances.Changes in strain biomass were monitored;The surface biodegradation process of polyester fibers was analyzed by SEM and super depth of field microscope;The types of intermediate products of polyester fiber biodegradation were analyzed by HPLC;Changes in thermal properties and surface chemical functional groups before and after degradation of polyester fibers were characterized by DSC and FTIR.It was found that the etching of the fiber surface was more pronounced when the calcium and magnesium ions and bio-auxiliaries were present;According to the DSC test and the peak area ratio method of FTIR,it was found that compared with the fibers treated with microorganisms,the crystallinity of the fibers increased more after being treated with microorganisms in the presence of calcium and magnesium ions and rhamnolipid;FTIR analysis showed that the types of functional groups on the surface of the polyester fibers did not change.PET/PLA blend films with different mass ratios prepared by solution blending method were for whole-cell catalytic degradation.Compared with the growth of the strains in the PET film culture solution,the growth of the strains in the culture solution of the PET/PLA film was better;SEM showed that the higher the PLA component content,the rougher the surface of the blended film,and the longer the time of microbial treatment,the more obvious the etching of the surface of the blended film;DSC showed that after microbial treatment,the crystallinity of films has increased;FTIR showed that after 4 weeks of strain treatment,the ester bonds on the surface of the PET films decreased,and the PET component on the surface of the PET/PLA films increased.Different biological treatment methods were constructed for the two types of polyester alkali-reduced wastewater.For simulated polyester alkali-reducing wastewater containing promoter 1227,after adding rhamnolipid to eliminate bactericidal effect of promoter 1227,97%of TA and 70%of COD were removed by strain treatment for 48h.For the alkali-reduced wastewater in actual production,an acid precipitation-whole cell catalytic combined processing method was constructed.After the wastewater was acid-filtered,the filtrate was biodegraded.After 120 hours of biodegradation,the removal rates of TA,EG,and COD were 50.24%,16.37%,and60.33%,respectively.