The Degradation Of Sulfamethazine By Microwave And Microorganism

With the rapid development of social economy, the antibiotics are substantially overused in medical treatment and breeding. It’s a normal phenomenon of adding antibiotics to animal feed in order to prevent disease. Many antibiotics which were unabsorbed and degraded were discharging into the environmental without supervision. The antibiotic in the environment can induce genes encoding antibiotic resistance. Antibiotic resistant genes are easily disseminated in the environment and can pollute food and drinking water, posing threats to human health and ecological environment. Therefore, the study on mechanism of the degradation of antibiotics to protect the ecological environment is very important.This paper took sulfamethazine (SM2) as the research object, and firstly determined the solubilities of sulfamethazine in different solvents. The result showed that the sulfamethazine had a very low solubility in chloroform, and a high solubility in1-propanol, acetone. The solubility increases with an increase of temperature.This dissolve process of sulfamethazine in five kinds of organic solvent can be well simulated by Apelblat equation.Microbial degradation was limited when the sulfamethazine concentration is high because the sulfamethazine can inhibit the growth of microorganisms as a broad-spectrum antibacterial agent. In order to reduce the concentration of sulfamethazine, this paper tried to degrade sulfamethazine with the microwave irradiation. It showed that the rate of degradation is low with the microwave irradiation. So H2O2was taken as the additive. The study found that in the sample water of40mL, the volume of H2O2is0.25mL, the concentration of sulfamethazine is50mg/L, the power of microwave radiation is900W, the treatment time is13min, the pH is6, the rate of degradation can reach up to97%. When improve the concentration of sulfamethazine to200mg/L, the degradation rate may still hit84%.The toxicology tests of degradation products were measured by using Colibacillus, Bacillus megaterium and Bacillus subtilis as test microorganism. And the results showed that the product of degradation has no inhibiting to microbiology. In order to investigate the long-term interaction between sulfamethazine and soil microorganisms, soil collected from livestock farm was studied and one bacterium which was primarily identified to be Klebsiella Trevisan and named SX5was separated as sulfamethazine-degrading bacteria. Subsequent experiments suggested that the half-life of sulfamethazine in culture medium without SX5was161.2d, and the half-life reduced to60.3d in culture medium added SX5. The results demonstrated that the bacteria named SX5could significantly promote the degradation of sulfamethazine, and provided indirect proof of the existence of the resistance gene.