Reduction Of Sulfadiazine Residues By Cell Surface Display Laccase Technology In Poultry Manure

Sulfonamide antibiotics have been widely used in poultry breeding industry because of disease resistance and growth-promoting effects.In particular,the rise of the concept of pharmaceutical health care in farms has pushed the use of sulfonamide antibiotics to a climax.The long-term abuse of antibiotics leads to high concentrations of antibiotic residues in poultry and its feces.The antibiotics released into the soil,waters and other ecological environments will induce drug-resistant bacteria and pose a serious threat to human health.At present,traditional physical and chemical methods for antibiotic degradation are usually expensive and has high risk of secondary environmental pollution.Therefore,developing an environmental friendly,method is the key to solving the problem of antibiotic residues in poultry manure.In this study,after comprehensive comparison of the existing methods of degradation of sulfadiazine,the cell surface display technology was used to display the laccase lacc6 derived from Pleurotus ostreatus HAUCC 162 was on the cell surface of probiotic E.coli Nissle 1917(EcN).In vitro testing indicated that the engineered strain had a laccase enzyme activity of 1.99 ± 0.87 U / mg dry weight of bacteria.The optimal temperature for the enzyme activity reaction was 40 ° C,and the optimal pH value was 5.0,the degradation rate of sulfadiazine can reach 37 ± 1.3%.Subsequently,we used white feather broilers as animal models,the whole-cell catalyst was prepared as a strain lyophilized powder and fed to broilers.After testing,it was found that the colonization of EcN-IL in the chicken intestine can reach 0.07%,and degradation rate of sulfadiazine in chicken manure reached 58 ± 2.3%.Illumina MiSeq sequencing of the cecum contents demonstrated that EcN-IL could alleviate the intestinal microflora disorder of broilers caused by long-term antibiotic treatment.Therefore,the whole-cell biocatalyst EcN-IL not only directly degraded antibiotics in chicken intestines,but also repair the intestinal disorder,thereby reducing the antibiotics residue in white feather broilers.This new method provided a theoretical basis for directly reducing antibiotic residues from broilers and lays a practical basis for its practical application.