APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2015
·Vol. 99
·期 10
·4485-4494
·
IF 3.337
Zhang Xueqin,Feng Huajun,Liang Yuxiang,Zhao Zhiqing,Long Yuyang,Fang Yuan,Wang Meizhen,Yin Jun,Shen Dongsheng
Low temperature aggravates biological treatment of refractory p -fluoronitrobenzene ( p -FNB) because of microtherm inhibition of microbial activity. Considering the potential characterization of energy supply for microbial metabolism and spurring microbial activity by electrical stimulation, a bioelectrochemical system (BES) was established to provide sustaining electrical stimulation for p -FNB mineralization at a low temperature. Electrical stimulation facilitated p -FNB treatment and bioelectrochemical reaction rate constants for the removal and defluorination of p -FNB at 10 °C were 0.0931 and 0.0054 h −1 , which were higher than the sums of the rates found using a biological system and an electrocatalytic system by 62.8 and 64.8 %, respectively. At a low temperature, microbial activity in terms of dehydrogenase and ATPase was found to be higher with electrical stimulation, being 121.1 and 100.1 % more active than that in the biological system. Moreover, stronger antioxidant ability was observed in the BES, which implied a better cold-resistance and relief of microtherm inhibition by electrical stimulation. Bacterial diversity analysis revealed a significant evolution of microbial community by electrical stimulation, and Clostridia was uniquely enriched. One bacterial sequence close to Pseudomonas became uniquely predominant, which appeared to be crucial for excellent p -FNB treatment performance in the BES at a low temperature. Economic evaluation revealed that the energy required to mineralize an extra mole of p -FNB was found to be 247 times higher by heating the system than by application of electrical stimulation. These results indicated that application of electrical stimulation is extremely promising for treating refractory waste at low temperatures.
研究领域:
环境科学
·
微生物学
✓ 已验证
DOI
PubMed
高影响因子
WATER RESEARCH
·
2014
·
IF 5.323
Huajun Feng,Xueqin Zhang,Yuxiang Liang,Meizhen Wang,Dongsheng Shen,Yangcheng Ding,Baocheng Huang,Jiali Shentu
p -Fluoronitrobenzene ( p -FNB) tends to accumulate in industrial effluents because of its recalcitrant properties. Approaches to the removal of p -FNB always encounter conflicts between treatment efficiency and economic efficiency. A bioelectrochemical system (BES) was established to facilitate the removal and mineralization of p -FNB. The treatment cost was reduced by using inexpensive electrode materials and reducing the electrical energy used. p -FNB was effectively removed using the BES, and the reaction rate was higher than the sum of the rates of two control systems, i.e., a biological system (BS) and an electrocatalytic system (ECS), by a maximum of 62.9% under a voltage of 1.4 V. The voltage is a crucial kinetic factor for the BES performance; as the voltage increased from 0 to 1.4 V, the reaction rate constants for p -FNB removal and defluorination increased from 0.0520 to 0.1811 h −1 and 0 to 0.0107 h −1 . The synergistic effect of multistrains gave a TOC removal efficiency in the BES of about 34.05%, yet the removal efficiencies were low for the two control. The defluorination reaction rate was significantly slower than the p -FNB removal rate, which indicated that defluorination lagged p -FNB removal, and p -FNB transformation to p -fluoroaniline ( p -FA) was the fastest step. The electrochemical assistance provided electrons and accelerated the electron transfer rate in the microbial reduction of p -FNB to p -FA. In this study, the critical voltage for defluorination in the BES was 0.8 V, which was approximately 0.2 V lower than that in the ECS. The decrease in the critical voltage for defluorination was based on the production of p -FA, which is more electrocatalytically activated. These results demonstrate the mechanism of efficient p -FNB removal and mineralization in a BES.
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Huajun Feng,Yanfeng Wang,Xueqin Zhang,Dongsheng Shen,Na Li,Wei Chen,Bin Huang,Yuxiang Liang,Yuyang Zhou
Biodegradation of p -fluoronitrobenzene ( p -FNB) regardless of effective p -FNB removal in a bioelectrochemical system (BES) was achieved for the first time in a biological system (BS). p -FNB degradation showed different kinetics, pathways, and microbial community evolutions in the two systems. About 36 d were required before 100% p -FNB removal in the BS p -FNB , while only 18 d were required in the BES p -FNB . Moreover, the reaction rate constant for p -FNB removal in the BES p -FNB was 1.625 times that in the BS p -FNB . The reduction of nitro groups was the key step for p -FNB removal in the BES p -FNB . However, defluorination was the first step for direct biodegradation of p -FNB in the BS p -FNB . Microbial community analysis showed that the dominant bacteria in the BES p -FNB (20.8% Anaerolineae, 15.9% Flavobacteriia, and 14.8% α-proteobacteria) differed greatly from those in the BS p -FNB (32.8% Flavobacteriia, 24.1% Clostridia and 19.2% Ignavibacteria). In the BS p -FNB , some aerobic microorganisms responsible for direct p -FNB biodegradation were enriched, while p -FA-degrading microorganisms were dominant in the BES p -FNB .
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2016
·
IF 3.698
Yanfeng Wang,Xueqin Zhang,Huajun Feng,Yuxiang Liang,Dongsheng Shen,Yuyang Long,Yuyang Zhou,Qizhou Dai
To verify the potentially synthetic anodic and cathodic biocatalysis mechanism in bioelectrocatalysis systems (BECSs), a single-chamber thermophilic bioelectrocatalysis system (R3) was operated under strictly anaerobic conditions using the biocathode donated dual-chamber (R1) and bioanode donated dual-chamber (R2) BECSs as controls. Direct bioelectrocatalytic oxidation was found to be infeasible while bioelectrocatalytic reduction was the dominant process for p -Fluoronitrobenzene ( p -FNB) removal, with p -FNB removal of 0.188 mM d −1 in R1 and 0.182 mM d −1 in R3. Cyclic voltammetry experiments confirmed that defluorination in the BECSs was an oxidative metabolic process catalyzed by bioanodes following the reductive reaction, which explained the 0.034 mM d −1 defluorination in R3, but negligible defluorination in controls. Taken together, these results revealed a sequentially combined reduction and oxidation mechanism in the thermophilic BECS for p -FNB removal. Moreover, the enrichment of Betaproteobacteria and uniquely selected Bacilli in R3 were probably functional populations for p -FNB degradation.
研究领域:
环境科学
·
微生物学
✓ 已验证
DOI
PubMed
高影响因子
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