Study On Treatment Of Hydrolyzed Cephalosporin Residue By Thermophilic Hydrolysis-Anaerobic Digestion

Antibiotics bacterial residue,which is a special kind of hazardous waste,has large production and potential environmental risk.How to deal with it reasonably and effectively has become a hot topic in current research.In this study,hydrolyse producing bacteria was isolated from compost substrate.And the effects of cultivation condition and nutritional factors on enzyme producting capability were also investigated.In addition,the fementation liquid containing hydrolase was added to cephalosporin mycelial dreg?CMD?to investigate the effect of different treatment methods and conditions on the hydrolysis of bacterial residue.The anaerobic digestion treatment were carried out to assess CBR biodegradability.Finally,the research system for the hydrolysis of thermophilic bacteria to strengthen CMD,which offer the technical and theoretical guidance for antibiotics bacterial residue treatment.The trials and mechanism studies mainly carried out are as follows:1)Eight strains of thermophiles with protease and amylase activity were isolated and purified from compost substrate at 60°C,named DF1^DF8.DF7,which has the highest protease and amylase activity in eight strains of thermophiles,was used as a model strain.It was identified by 16SrDNA as belonging to the genus Bacillus thermocopriae.The lytic performance was verified and the extracellular enzyme pair of DF7 strain was found.The E.coli dissolution rate reached 67%at 14 h,which was 3.2 times of the control group.Under35%?V/V?of the optimized dosage ratio of DF7 to CMD,the extracellular enzyme of the thermophilic bacteria had the best hydrolysis effect on the cephalosporin mycelial dreg,and the hydrolysis rate was up to 74.99%,which was 31.41%higher than that obtained in the control.2)The FDA hydrolase activity(333.45?gFDA·mL^-1h^-1),was 3.2-fold of that obtained in the control.This was achieved under the following conditions:DF7 dosage was 10%?V/V?,and the temperature was 60°C.The corresponding performances of CMD solubilization were as follows:16255mg·L^-1 of SCOD,611.4mg·L^-1 of NH₄⁺-N,and182.46mg·L^-1 of soluble protein,which were 1.1-fold,1.2-fold and 1.4-fold high of that obtained in the control,respectively.The results of metal ion-enhanced thermophilic bacteria hydrolysate showed that the K⁺hydrolysis effect was the best at 200?mol·L^-1.The corresponding performances solubilization were as follows:18285mg·L^-1 of SCOD,570.42mg·L^-1 of NH₄⁺-N,which increased by 12.66%and 13.28%compared with obtained in the control.3)Methane production by anaerobic digestion tests were carried out to evaluate the effect of both thermophilic bacteria and K⁺enhancement condition on residue subsequent anaerobic digestion.The K⁺enhanced hydrolysis was the optimum,under the condition of1.0kgCOD·m^-3·d^-1 of organic load,which highest daily yield of methane was 106mL and COD decrement rate was 97.74%,increased by 47.22%and 4.1%compared with obtained in the control.The highest NH₄⁺-N concentration was 132.18 mg·L^-1,which was 36.52%lower than the obtained in the control.