Relationship between Biodegradation of Sulfonamides and Bacterial Community Change in Estuarine Sediment

Autor: TASI,LI-LING, 蔡莉翎
Rok vydání: 2016
Druh dokumentu: 學位論文 ; thesis
Popis: 104
Sulfonamides are common medical antibiotics, and often adds to animal feeds to prevent infections. Due to sulfonamides presence in the original form from the animal faeces, the traditional wastewater treatment plant is unable to process completely. Microbial transformation and degradation is the principal practical processes currently known for successful removal of sulfonamides from sediments. The purpose of this study is to investigate aerobic and anaerobic biodegradation of sulfonamides in different sampling sites and seasons of estuarine sediments, as well as to establishing an optimum system. Sucrose was added in anaerobic degradation. Spent mushroom compost (SMC) and spent mushroom compost extract (CE) were added in aerobic degradation. Degraded the different concentration of sulfamethoxazole(SMX) and different kinds of sulfonamides, sulfadimethoxine(SDM) and sulfamethazine(SMZ) alone or mixed, then carried out the bioreactor experiment. Finally, we attempted to use pyrosequencing technology for profiling microbial communities involved in these chemicals transformation and degradation. The results showed that anaerobic degradation treated with sucrose and aerobic degradation treated with CE could accelerate the degradation of sulfonamides. The half-life (t½) of anaerobic batch experiments of Guandu sample with sucrose was 0.7 days, which was better than inoculated control (2.4 days). Aerobic batch experiments which added CE (1.3 days) was better. The results of the Bali and Guandu were the same. Batch experiments were performed with different concentration SMX or different sulfonamides alone or mixed. The results showed that only SMX could be removed in the anaerobic experiments, the remaining of SDM and SMZ were up to 70 %. Moreover, SMX in both of spring and Guandu in autumn samples could be degraded to N.D.(Not Detected, < 0.02 mg/L), the remaining of SMX 20, 50, 100 mg/L and mixed sulfonamides were 8.3 %, 2.2 %, 6.7 % and 19.5 %. SMX、SDM and SMZ could be degraded in the aerobic experiments. Sulfonamides in spring of Guandu sampling sites could be removed except SMZ in single and mixed, the remaining were 13.1 % and 25.0 %. The autumn of Guandu sampling sites, only the single groups with sucrose could degrade to N.D., the remaining of SMX 50 and 100 mg/L、mixed group SDM and SMZ were 38.1 %、75.2 %、37.9 %、31.8 % and 37.4 %. Spring of Bali sampling sites only SMZ could not degrade to N.D., the remaining of single and mixed were 24.9 % and 20.1 %. Experiments in autumn were incompletely degraded, the remaining were still more than 45 %. The above results showed that the ability of degradation in spring was better than in autumn, Guandu was better than Bali. In SMX, anaerobic biodegradation was better than aerobic but SDM and SMZ were the opposite results. The capability of degradation in sulfonamides were different in various environmental samples. In the experiments of bioreactor, with the increasing in the number of times addition, the ability of degradation was enhanced regardless of in aerobic or anaerobic experiments. At last, the degradation rate of inoculated control did not have significant differences to the experiments with sucrose or CE. Aerobic was more excellent, the half-life (t½) was 0.5-1.6 days < 0.9-2.7 days. In the microbial community analysis, sequences obtained from pyrosequencing were compared with sequences in Ribosomal Database Project (RDP). The batch experiments found Chryseobacterium spp.、Turicibacter spp.、Propionicimonas spp、Stenotrophomonas spp.、Shewanella spp.、Clostridium XI spp.、Clostridium sensu stricto spp.、Sphingopyxis spp.、Brevibacillus spp.、Clostridium XlVa spp.、Hydrogenophaga spp.、Sphingobium spp.、Sphingomonas spp.、Sphingobacterium spp.、Steroidobacter spp.、Planctomyces spp.、Altererythrobacter spp.、Raoultella spp.、Arenibacter spp.、Acidovorax spp.、Shinella spp.、Phenylobacterium spp.、Muricauda spp.、Marinobacter spp.、Alcaligenes spp.、Rhodanobacter spp. Flavisolibacter spp.、Nitrosomonas spp. might be related to the degradation of sulfonamides. Acinetobacter spp., Pseudomonas spp., Rhodococcus spp.、Microbacterium spp.、Achromobacter spp. and Oligotropha spp. could degrade sulfonamides. In different seasons, sites and degradation ways, causing different physical and biological factors between samples, the capability of degradation SMX, SDM and SMZ will have different results. Hope that the research can provide more varied condition to deal with the sulfonamides contaminated in estuarine sediment of environmental bioremediation in the future.
Databáze: Networked Digital Library of Theses & Dissertations
Externí odkaz: