Lactiplantibacillus Plantarum CGMCC18980 Study On The Adsorption Mechanism Of Dibutyl Terephthalate

The plasticizer represented by dibutyl phthalate(DBP)is an environmental hormone widely present in life,which can disrupt the normal endocrine system of the human body and affect the level of hormones in the body.It is easy to accumulate in the food chain over time,and it is difficult to degrade in the natural environment.Lactic acid bacteria are a kind of microorganisms that are widely used and have important probiotic effects.In recent years,more and more studies have used lactic acid bacteria as biosorbents to remove pollutants in the environment.This method is safe,effective,convenient and fast.In this paper,lactic acid bacteria adsorb DBP and other pollutants in vitro to reduce the damage caused by plasticizer compounds.In this paper,by optimizing the adsorption conditions of Lactiplantibacillus plantarum CGMCC18980 in vitro,the adsorption mechanism was further studied.The results show that when OD600=4.0,DBP concentration is 5.00 mg/mL,temperature is 37?,the adsorption effect is the best when standing incubation for 2.5 h,and the adsorption rate can reach 58.63%.Observe the changes of the cell surface before and after adsorption by scanning electron microscope(SEM)and transmission electron microscope(TEM).A significant adsorption layer was observed on the surface of the lactobacillus after the adsorption of DBP.The thickness of the adsorption layer increased from 0.1172±0.0019 ?m to 0.6296±0.0409 ?m.By infrared spectroscopy,the main functional groups involved in the adsorption are C=O,C-N,and C-O,and it is speculated that the main component involved in the adsorption process is exopolysaccharides;Zeta potential analysis results show that the adsorption of DBP has no obvious relationship with the surface charge.Through genetic engineering,the key enzyme UDP-glucose epimerase in the extracellular polysaccharide synthesis pathway of Lactobacillus was overexpressed.By increasing the content of polysaccharides,the adsorption rate of the modified bacteria on DBP increased by 10.81%,further reducing the toxicity of dibutyl phthalate compounds.