INTERNATIONAL BIODETERIORATION & BIODEGRADATION
·
2015
·
IF 2.131
Yuancai Lv,Lianghao Li,Yuancai Chen,Zhenghua Tang,Yongyou Hu
Polybrominated diphenyl ethers (PBDEs) are emerging persistent organic pollutants and the degradation of PBDEs is still a tremendous challenge owing to their extreme persistence and recalcitrance. In this study, Pseudomonas putida was employed for bioremediation of four PBDE congeners (BDE47, 15, 3 and diphenyl ether (DE)) with an initial concentration of 2 mg/L and the cometabolism of PBDEs was illustrated via kinetics analysis and metabolic mechanism. The biodegradation kinetics analysis suggested that PBDEs was inversely proportional to the number of bromine substituted on diphenyl ether. Both glucose (24 mg/L) and biphenyl (10 mg/L) played a positive role in promoting the biodegradation of PBDEs. The growth kinetics analysis indicated that glucose had uncompetitive inhibition on PBDEs consumption while both competitive and uncompetitive inhibition existed in biphenyl-PBDEs binary substrate system. Furthermore, the intermediates were identified by GC–MS and the main tentative degradation pathways were proposed. The angular dioxygenation was the main pathway for PBDEs degradation, while lateral dioxygenation could be induced when biphenyl was added.
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BIORESOURCE TECHNOLOGY
·
2019
·
IF 6.669
Lei Yang,Xu-Hui Wang,Shen Cui,Yong-Xiang Ren,Jie Yu,Ning Chen,Qian Xiao,Lin-Kai Guo,Rui-Hua Wang
A novel strain NP5 with efficient heterotrophic nitrification, aerobic denitrification and phosphorus accumulation ability was isolated and identified as Pseudomonas putida strain NP5. The removed ammonium and phosphate were mainly converted into intracellular components by assimilation, and negligible nitrification intermediates and N 2 O were accumulated during heterotrophic nitrification. In addition, the optimal conditions for nutrient removal were: succinate as carbon source, C/N 10, P/N 0.2, temperature 30 °C, salinity 0% and shaking speed 160 rpm. Besides, strain NP5 possessed an exceptional heavy metal and nanoparticles resistance. Cr 6+ was found to be the most toxic among the tested metals, and it could be removed simultaneously. Moreover, an obvious phosphorus release was observed under anaerobic condition, and repeated exposure to the anaerobic/aerobic conditions could significantly improve the nutrient removal. Furthermore, the successful expression of key enzymes for nitrogen and phosphorous removal provided additional evidence for possibility of simultaneous nitrification, denitrification and phosphorus removal.
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Journal of Environmental Chemical Engineering
·
2025
·Vol. 14
·期 1
·120844
·
IF 7.2
Xinyu Zhang,Yujie Liu,Ziling Yuan,Haomin Chen,Danyang Ma,Bingzhi Li,Ruihua Liu,Chao Yang
In this study, to remediate 1,2-dichloroethane (DCA)- and 2,4-dichlorophenoxyacetic acid (2,4-D)-polluted wastewater, an autofluorescent engineered strain KTU-DDGV was constructed from a biosafety strain Pseudomonas putida KT2440 by the implantation of the DCA and 2,4-D mineralization pathways, green fluorescent protein (GFP) and Vitreoscilla hemoglobin (VHb). All exogenous genes stably existed in passage cultures of strain KTU-DDGV. The successful transcription of all fourteen exogenous genes in strain KTU-DDGV was confirmed by RT-PCR. Chromatographic analysis demonstrated that strain KTU-DDGV was able to degrade DCA, 2,4-D and their intermediates. The capacity of strain KTU-DDGV to mineralize DCA and 2,4-D was further confirmed by stable isotope assay. When strain KTU-DDGV was incubated with 13 C-labeled DCA and 2,4-D, the 13 C-labeled CO 2 was detected in the collected gases using an isotope mass spectrometer, demonstrating that strain KTU-DDGV was capable of converting 13 C 2 -DCA and 13 C 6 -2,4-D into 13 CO 2 , cell biomass and cellular components. Under oxygen-limited conditions, strain KTU-DDGV still possessed the capability to co-degrade DCA and 2,4-D. The strain KTU-DDGV exhibits visible green fluorescence with naked eyes under daylight, enabling real-time monitoring of strain KTU-DDGV in polluted environments. During wastewater remediation, strain KTU-DDGV maintained high viability and showed high mineralization efficiency for DCA and 2,4-D. This study highlights the potential of strain KTU-DDGV for in situ bioremediation of DCA- and 2,4- D -polluted wastewater. More importantly, constructing composite degradation circuits in a robust chassis may serve as a useful strategy to cope with multiple organic pollutants.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2022
·
IF 5.895
Ya’nan Shi,Rongshan Li,Jie Zheng,Yubin Xue,Yong Tao,Bo Yu
Bio-based propionate attracts increasing attention owing to its green nature and specific food additive market. To date, the time-consuming and costly fermentation process by strict anaerobes makes propionate production not ideal. In this study, we designed a new route for propionate production, in which 1,2-propanediol was first dehydrated to propionaldehyde and then to propionate by taking advantage of the robust oxidization capacity of the Pseudomonas putida KT2440 strain. The high atom economy (0.97 g/g) in this proposed pathway is more advantageous than the previous l-threonine-derived route (0.62 g/g). The molecular mechanism of the extraordinary oxidation capacity of P. putida KT2440 was first deciphered. The propionate production was realized in P. putida KT2440 by screening suitable glycerol dehydratases and optimizing the expression to eliminate the formation of 1-propanol and the accumulation of the intermediate propionaldehyde. The engineered strain produced propionate with a molar conversion rate of >99% from 1,2-propanediol. A high titer of 46.5 g/L pure propionic acid with a productivity of 1.55 g/L/h and a mass yield of 0.96 g/g was achieved in fed-batch biotransformation. Thus, this study provides another idea for the production of high-purity bio-based propionate from renewable materials with high atom economy.
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高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 30
·期 10
·28227-28237
·
IF 5.19
Liu Huan-Huan,Yang Lei,Guo Lin-Kai,Tu Li-Xin,Li Xiao-Tong,Wang Jia,Ren Yong-Xiang
The occurrence of metal oxide nanoparticles (NPs) in wastewater treatment plants (WWTPs) has raised great concerns about their adverse impacts on nitrification performance. In this study, a heterotrophic nitrifying bacterium Pseudomonas putida strain NP5 showed strong resistance against TiO 2 and NiO NPs. Under 5–50 mg/L NP stress, cell viability was still normal, and the final nutrient removal rates, always higher than 80%, were slightly inhibited. Correspondingly, the PO 4 3− -P removal rates were almost the same as those observed in the control test. Although the enzyme assay demonstrated ammonia monooxygenase and hydroxylamine oxidoreductase activities markedly decreased caused by increased reactive oxygen species (ROS) level under 50 mg/L NPs stress. The total antioxidant capability of NP5 could eliminate excess ROS to maintain a balance between oxidants and antioxidants. Besides, in response to the escalating burden of NPs, strain NP5 tended to secrete more extracellular polymeric substances (EPS), which could protect cell from being damaged by binding to ions and coating. Thus, the strong NP resistance of NP5 would help to overcome the vulnerability of the nitrification process in WWTPs.
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APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2016
·Vol. 181
·期 3
·972-985
·
IF 1.606
Wu Hua-Lei,Zhang Jian-Dong,Zhang Chao-Feng,Fan Xiao-Jun,Chang Hong-Hong,Wei Wen-Long
Four uncharacterized ω-transaminases (ωTAs) from Pseudomonas putida NBRC 14164 have been identified and cloned from the pool of fully sequenced genomes. The genes were functionally expressed in Escherichia coli BL21, and the enzymes were purified and characterized. Four TAs showed highly ( S )-selective ωTA activity and converted ( S )-α-methylbenzylamine and pyruvate to acetophenone and l -Ala. The maximum activity of cloned enzymes was in the pH range of 8.0– 8.5 (Pp36420), 8.5 –9. 5 (Pp21050), 9 .0– 9.5 (PpspuC), and 9.5 –1 0 . 5 (PpbauA), and the optimal temperatures were at 35 °C (Pp36420, Pp21050, and PpspuC) and 50 °C (PpbauA), respectively, with K
M of 161.3 mM (Pp21050), 136.7 mM (PpbauA), 398.5 mM (Pp36420), and 130.9 mM (PpspuC) and yielding a catalytic efficiency k
cat / K
M of 0.015, 0.003, 0.012, and 0.023 mM −1 s −1 . Several racemic amines and amino alcohols were resolved by the cloned ωTAs; perfect conversions (48–50 %) were obtained by at least one enzyme, and the residual substrates were left with 97–99 % ee. Kinetic resolution of racemic phenylglycinol was done with PpspuC in a 100-mL scale. Enaniomeric excess of ( S )-phenylglycinol reached 99 % with 45 % isolated yield. The high enantioselectivity and large substrate spectra of the cloned PpTAs showed an attractive potency for biotechnology application in production of chiral amines and amino alcohols.
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APPLIED AND ENVIRONMENTAL MICROBIOLOGY
·
2026
·
IF 4.2
Haiqin Meng,Shun Pan,Zening Chai,Lixiang Zhou,Tianyu Zheng,Hanyu Zhang,He Fu,Lei Zou,Dongqi Liu,Jingcheng Dai,Dazhong Yan,Hong-Jun Chao
The catabolism of the priority environmental pollutant 2,4-xylenol requires bacteria to oxidize its ortho-methyl group. Its exact biochemical mechanism is uncharacterized until now. In this study, we resolve key metabolic bottlenecks in Pseudomonas putida NCIMB 9866. We demonstrate that functionally redundant Rieske oxygenase systems ensure the robust ortho-methyl oxidation of 2,4-xylenol. On the para-methyl oxidation branch, PchA2 acts as the main aldehyde dehydrogenase. It shows significantly higher catalytic efficiency than the previously reported PchA. Additionally, we characterized PmmA1B1, a newly identified three-component Rieske oxygenase system responsible for ortho-methyl oxidation, which is supported by two redundant isoenzymes (PmmA2B2 and PmmA3B3), by recruiting the shared endogenous ferredoxin Orf05169. The PmmA1B1-Orf05169 system catalyzes the successive oxidation of the ortho-methyl group of 4-hydroxy-3-methylbenzoate to a carboxyl group, yielding the high-value pharmaceutical precursor 4-hydroxyisophthalate. Structural and kinetic data revealed that the active site architecture of PmmA1 enables efficient successive oxidation, distinguishing it from isoenzymes PmmA2B2 and PmmA3B3 that, when coupled with Orf05169, catalyze only incomplete oxidation. Overall, these results complete the 2,4-xylenol catabolic pathway by defining the enzymes required for both para- and ortho-methyl oxidation. They also reveal functional redundancy as an adaptive feature of microbial aromatic degradation and establish Rieske oxygenases as biocatalysts for converting methylated aromatic pollutants into value-added chemicals.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 32
·48638-48647
·
IF 5.19
Li Qian,Tang Zeqin,Zhang Jiahui,Hu Jingtao,Chen Jianmeng,Chen Dongzhi
Simultaneous biodegradation of malodorous 1-propanethiol (PT) and dimethyl sulfide (DMS) by Pseudomonas putida S-1 and Alcaligenes sp. SY1 was investigated and the interactions implicated were explored. Results showed that PT was completely degraded in 33 h, while a lag of 10 h was observed for DMS degradation alone, and the lag was even extended to 81 h in the binary mixture. Mechanism analysis found that the lag was mainly attributed to the exposure of DMS degrader ( Alcaligenes sp. SY1), rather than PT metabolites and PT degrader. The exposure time and PT concentration also influenced the lag duration much. Citric acid could effectively reduce the lag. Pseudo-first-order model was proved suitable for the description of PT degradation, revealing that PT degradation could be enhanced in presence of DMS with a concentration of < 50 mg L −1 . A modified Gompertz model, incorporated the lag phase, was developed for the description of DMS degradation in the mixture, revealing that DMS degradation depended on the initial PT concentration, and when the lag was not considered, PT with low-concentration could promote DMS biodegradation, while a higher concentration (> 20 mg L −1 ) cast negative effect.
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INTERNATIONAL MICROBIOLOGY
·
2024
·
IF 2.3
Zhang Mingle,He Zhimin,Xu Xiaoyi,Ji Fan,Wang Bin
This study investigates the advantages of combined microbial degradation of polycyclic aromatic hydrocarbons (PAHs) in reducing the inhibitory effects of high-concentration eluents commonly used in soil washing. A microbial synergistic strategy was proposed using Arthrobacter sp. SZ-3 and Pseudomonas putida B6-2 as the key bacteria in the presence of Tween 80. The results show that in systems with Tween 80, the SZ-3 strain exhibits a strong capacity to degrade three types of PAH compounds, while the B6-2 strain follows multiple degradation pathways. Mixed bacteria achieved degradation rates 60.70% higher than single bacteria at varying concentrations of Tween 80. Additionally, the average growth rates of mixed bacteria increased by 1.17–1.37 times, aligning with the changes in the functional group. Protein activity detection within each degradation system corresponded with growth quantity and the cyclic variation characteristics of ETS enzyme activity. Notably, the ETS activity of mixed bacteria was 150% higher than that of single bacteria. At a Tween 80 concentration of 500 mg/L, the degradation rates of PAHs (Phe, Flu, Pyr) by mixed bacteria were significantly higher than those by single bacteria. The catechol 1,2-dioxygenase activity of mixed bacteria was 2.30 times higher than that of single bacteria. While Tween 80 did not alter the PAH degradation pathways, it significantly influenced the accumulation amount and duration of the characteristic intermediate product. This provides a reference for the remediation of recalcitrant pollutants under conditions involving high-concentration surfactants.
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Bioresources and Bioprocessing
·
2018
·Vol. 5
·期 1
·1-11
·
IF 0
Liu Xin,Wang Weiwei,Hu Haiyang,Lu Xinyu,Zhang Lige,Xu Ping,Tang Hongzhi
Background Benzofuran and its derivatives contain central pharmacophores and are important structures in medicinal chemistry. Chemical synthesis of benzofuran rings often requires expensive catalysts and stringent operational conditions. Biosynthesis is recognized as a promising way to save energy and produce valuable compounds. Dioxin biodegradation pathways can form several benzofuran derivatives, and these pathways may be a better choice for further synthesis of important biological compounds. 2-Hydroxy-4-(3′-oxo-3′ H -benzofuran-2′-yliden)but-2-enoic acid (HOBB), a benzofuran derivative, can be biosynthesized from dibenzofuran (DBF) through co-metabolic degradation in a lateral dioxygenation pathway. Results Efficient biosynthesis of HOBB was observed using whole cells of Pseudomonas putida strain B6-2. After cultivation in LB medium containing biphenyl, the cells were suspended to an OD 600 of 5 to conduct biosynthesis in the presence of 0.5-mM DBF at pH 7 for 8 h. The bacterial cells were used twice to degrade approximately 0.70-mM DBF, and in batch process, accumulated about 0.29-mM HOBB. HOBB could be easily purified from the reaction with ethyl acetate using the neutral-acid extraction method, and 13.58 ± 0.31 mg of HOBB was obtained from 22.49 ± 0.74-mg DBF with an overall production yield of 60.4% (w/w). The product HOBB, which is a yellow powder, could be detected and identified by LC–MS, GC–MS, and NMR. Conclusions In this study, a new biological route was developed to produce HOBB from DBF using whole cells of P. putida B6-2 (DSM 28064). The biosynthesis of HOBB may contribute to studies of the DBF lateral pathway and provide a new green route for synthesizing benzofuran derivatives with pharmacological activities.
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Fermentation-Basel
·
2021
·Vol. 7
·期 4
·309
·
IF 3.975
Yiming Sun,Xiaowei Lin,Shaodong Zhu,Jianmeng Chen,Yi He,Yao Shi,Hua Liu,Lei Qin
The biotrickling filter (BTF) treatment is an effective way of dealing with air pollution caused by volatile organic compounds (VOCs). However, this approach is typically used for single VOCs treatment but not for the mixtures of VOC and volatile organic sulfur compounds (VOSCs), even if they are often encountered in industrial applications. Therefore, we investigated the performance of BTF for single and ternary mixture gas of dimethyl sulfide (DMS), propanethiol, and toluene, respectively. Results showed that the co-treatment enhanced the removal efficiency of toluene, but not of dimethyl sulfide or propanethiol. Maximum removal rates (rmax) of DMS, propanethiol and toluene were calculated to be 256.41 g·m−3·h−1, 204.08 g·m−3·h−1and 90.91 g·m−3·h−1, respectively. For a gas mixture of these three constituents,rmaxwas measured to be 114.94 g·m−3·h−1, 104.17 g·m−3·h−1and 99.01 g·m−3·h−1, separately. Illumina MiSeq sequencing analysis further indicated that Proteobacteria and Bacteroidetes were the major bacterial groups in BTF packing materials. A shift of bacterial community structure was observed during the biodegradation process.Keywords:biotrickling filter;decomposition;dimethyl sulfide;pollution;propanethiol;toluene
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