ENZYME AND MICROBIAL TECHNOLOGY
·
2019
·
IF 3.553
Li-Quan Ren,Tian-Tian Chang,Da-Peng Ren,Ying Zhou,Bang-Ce Ye
Acinetobacter sp. strain LMB-5 can produce a kind of esterase degrading phthalate esters. However, low activity of Est3563 esterase limited its large-scale application. In this study, computer-aided simulation mutagenesis was used to improve the esterase activity with a tightened screening library and enlarged success rate. Two positive mutants, P218R and A242R, were obtained with 2.5 and 2.1 folds higher than the WT Est3563 esterase, with 11.96 ± 0.45 U·mg −1 and 9.90 ± 0.52 U·mg −1 , respectively. With the help of bioinformatics analysis and three-dimensional printing technology, it was found that the mutations could increase the 240–280 residues swing distance and make them deviate from the catalytic pocket. The instability and deviation of these residues on the lid-like structure of the esterase could deteriorate the seal of the binding pocket and expose the active site. Thus, the catalytic efficiency of the mutants became higher. This result demonstrates that the instability and deviation of the lid-like structure could expand the binding pocket of the esterase and enhance the esterase activity.
研究领域:
酶学
·
生物化学
·
生物技术
·
计算生物学
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Shijie Yao,Yaru Hu,Jianfeng Ye,Jianhao Xie,Xuetao Zhao,Lingli Liu,Shuguang Lyu,Kuangfei Lin,Changzheng Cui
The super-resistant bacteria that produce the New Delhi metallo-β-lactamase 1 (NDM-1) enzyme are becoming a conceivably major worldwide clinical issue with serious consequences. Studying the disinfection and mechanism of super-resistant bacteria and their antibiotic resistance genes (ARGs) is crucial for controlling their spread in the water environment. In this study, the disinfection of the super-resistant bacterium Acinetobacter sp. CS-2 and its transferable ARGs (plasmid-encoded bla NDM-1 and bla OXA-58 ) by ultraviolet radiation (UV), peroxymonosulfate (PMS), and ultraviolet/peroxymonosulfate (UV/PMS) exposure were investigated. UV/PMS could completely inactivate CS-2 and control the photoreactivation risk, while bacteria that underwent UV and PMS treatment had survival ratios of 0.22% and 0.28%, respectively. The removal efficiencies of bla NDM-1 and bla OXA-58 ranged from 3.64 to 4.05 log, and the advantage of UV/PMS treatment on ARGs damage was further identified by gel electrophoresis analysis. The removal efficiency of bla NDM-1 was lower than that of bla OXA-58 , which was attributed to the low number of adjacent 5′-TT-3′ harbored by bla NDM-1 . The removal rate constants of the ARGs by UV treatment were significantly correlated with the number of adjacent base pairs (e.g., 5′-TT-3′, 5′-CT-3′, 5′-TC-3′ and 5′-CC-3′) and length, with R -values ranging from 0.9044 to 0.9512. Singlet oxygen ( 1 O 2 ) played a vital role in the reduction of bla NDM-1 and bla OXA-58 in the UV/PMS treatment. UV/PMS showed high removal efficiency under natural pH conditions and in the presence of various aqueous ions (e.g., Cl − , SO 4 2− and HCO 3 − ). Overall, this study provides new understandings and theoretical support for the risk control of super-resistant bacteria and plasmid-encoded ARGs.
研究领域:
环境科学
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微生物学
·
分子生物学
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高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2018
·
IF 4.005
Shizong Wang,Yuming Hu,Jianlong Wang
A novel sulfamethoxazole (SMX)-degrading strain, Acinetobacter sp., was used to degrade other pharmaceutical compounds, including sulfadiazine (SD), sulfamethazine (SMT), trimethoprim (THM), triclosan (TCS), diclofenac (DFC) and carbamazepine (CBZ). The experimental results showed that Acinetobacter sp. can completely degrade SMX, SD and SMT, but with different mineralization efficiency. Acinetobacter sp. can mineralize 98.8% of SMX, while only 17.5% and 20.5% for SD and SMT, respectively. The intermediate products of SMX, SD and SMT degradation were tentatively identified. Based on the intermediates, it is inferred that the initial step for degrading sulfonamides by Acinetobacter sp. was the amidation of the amino groups in the benzene ring . The presence of methyl in the heterocyclic ring could induce the formation of methylase. By comparing the intermediates of SMX, SD and SMT degradation, it is concluded that Acinetobacter sp. preferred attacking the oxazole ring. However, Acinetobacter sp. cannot degrade THM, TCS, DFC and CBZ, while Acinetobacter sp. can still degrade SMX in the respective presence of THM, DFC and CBZ, although the degradation rate decreased. Moreover, the presence of TCS could completely inhibit the degradation of SMX by Acinetobacter sp.
研究领域:
环境科学
·
微生物学
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PubMed
高影响因子
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2017
·Vol. 102
·期 1
·425-432
·
IF 3.42
Wang Shizong,Wang Jianlong
In this study, a novel strain capable of degrading sulfamethoxazole (SMX) was isolated and identified as Acinetobacter sp. The effect of influencing factors, such as initial SMX concentration (5–240 mg/L), temperature (15–35 °C), and pH (5–7), on SMX degradation was investigated. The results showed that when the initial SMX concentration was in the range of 5–240, the removal efficiency was 100%. The optimal condition for SMX biodegradation and microbial growth was determined to be 25 °C and pH = 7.0 in terms of the removal efficiencies of SMX and total organic carbon (TOC). Four metabolite compounds were detected during the process of SMX biodegradation, and the degradation pathways were tentatively proposed. In summary, Acinetobacter sp. was highly efficient in mineralizing SMX, which has the potential to be used for degrading SMX in water and wastewater.
研究领域:
环境微生物学
·
水处理
·
生物技术
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高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2026
·
IF 6.7
Kou Boxiang,Yue Yufei,Wang Lei,Ma Dan,Sun Zhongsen,Liu Yuwei,Zhang Zilian,Dong Sijun
The accumulation
of acetaminophen (APAP) in agricultural soils
and water systems poses risks to ecosystems and public health. This
study characterizes Acinetobacter sp. DL27, an APAP-degrading
strain with broad temperature and pH adaptability, demonstrating its
bioremediation potential in soil and wastewater. Through high-resolution
mass spectrometry, we identified three novel metabolic intermediates,
thereby refining the bacterial APAP degradation pathway. Multiomics
analysis elucidated metabolic coordination and stress-tolerance mechanisms,
leading to the identification of a novel amidase (AdA). Recombinant
AdA exhibited activity over 10–60 ° C and pH 4.0–10.0,
with a K m of 8.96 ±
1.03 μM and a k cat / K m of 9.04 μM –1 s –1 , indicating higher catalytic efficiency than
previously reported APAP amidases. Molecular dynamics simulations
and site-directed mutagenesis confirmed that a Ser161–Ser185–Lys82
triad constitutes the catalytic center driving amide cleavage. These
findings provide mechanistic insights into bacterial APAP biodegradation
and highlight the practical application potential of strain DL27 and
AdA.
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高影响因子
AICHE JOURNAL
·
2026
·
IF 4.4
Pei Qiao,Yi Guo,Yanan Liu,Chenghua Zhu,Di Cheng,Youshan Zhou,Panpan Song
Phthalate esters (PAEs) are pervasive environmental pollutants that require efficient biodegradation. The substrate specificity of PAEs-degrading microorganisms hinges critically on the catalytic selectivity of microbial esterases. To elucidate the molecular basis of the specificity of Type III PAEs esterases, we developed a chromogenic assay and further integrated machine learning-driven enzyme mining with functional characterization and molecular dynamics analysis. A novel microorganism, Acinetobacter sp. DY-1, was isolated with diverse PAEs-degrading capacities. The esterase 1952 from strain DY-1 exhibited broad substrate specificity and high catalytic efficiency, with a marked preference for long-chain PAEs, such as DEHP. Molecular dynamics simulations revealed stable hydrophobic interactions underpinning 1952s affinity for DEHP. Through targeted mutagenesis, we identified key residues (Leu64, Leu68, and His229) that are essential for substrate binding and catalysis. Their substitution with polar residues drastically reduced DEHP degradation, while the G178Y mutant enhanced activity via π-stacking interactions. This study deciphers the structural determinants of PAE esterase specificity, enabling precise enzyme engineering.
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高影响因子
MOLECULES
·
2023
·Vol. 28
·期 18
·6738
·
IF 4.6
Shuanghu Fan,Jingjing Guo,Shaoyan Han,Haina Du,Zimeng Wang,Yajuan Fu,Hui Han,Xiaoqiang Hou,Weixuan Wang
Phthalic acid esters (PAEs), which are widespread environmental contaminants, can be efficiently biodegraded, mediated by enzymes such as hydrolases. Despite great advances in the characterization of PAE hydrolases, which are the most important enzymes in the process of PAE degradation, their molecular catalytic mechanism has rarely been systematically investigated.Acinetobactersp. LUNF3, which was isolated from contaminated soil in this study, demonstrated excellent PAE degradation at 30 °C and pH 5.0–11.0. After sequencing and annotating the complete genome, the genedphAN1, encoding a novel putative PAE hydrolase, was identified with the conserved motifs catalytic triad (Ser201-Asp295-His325) and oxyanion hole (H127GGG130). DphAN1 can hydrolyze DEP (diethyl phthalate), DBP (dibutyl phthalate) and BBP (benzyl butyl phthalate). The high activity of DphAN1 was observed under a wide range of temperature (10–40 °C) and pH (6.0–9.0). Moreover, the metal ions (Fe2+, Mn2+, Cr2+and Fe3+) and surfactant TritonX-100 significantly activated DphAN1, indicating a high adaptability and tolerance of DphAN1 to these chemicals. Molecular docking revealed the catalytic triad, oxyanion hole and other residues involved in binding DBP. The mutation of these residues reduced the activity of DphAN1, confirming their interaction with DBP. These results shed light on the catalytic mechanism of DphAN1 and may contribute to protein structural modification to improve catalytic efficiency in environment remediation.Keywords:Acinetobacter;biodegradation;genome sequencing;HSL family hydrolase;site-directed mutagenesis
研究领域:
环境科学
·
微生物学
·
分子生物学
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高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2018
·
IF 3.974
Xiaoxin Chen,Sheng He,Xiaolu Liu,Jiye Hu
Using sequential soil and liquid culture enrichments with cyprodinil as the sole carbon source, a Gram-negative cyprodinil-degrader from cyprodinil-polluted agricultural soil was isolated. The sequencing analysis of 16 S rRNA indicated that the strain showed 99% homology to Acinetobacter sp. The strain could effectively degrade cyprodinil at the neutral condition. At the initial concentrations of 10, 20, 50, 100, 150 and 200 mg L −1 in minimal medium, cyprodinil was degraded by 10, 20, 49.3, 64.2, 57 and 24 mg L −1 within 14 days, respectively. Two metabolites (4-cyclopropyl-6-methyl-2-pyrimidpyridine amine and monohydroxylated para-substitution) were identified using high performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS/MS). A biodegradation pathway involving imines hydrolysis and monohydroxyl substitution on benzene ring was proposed on basis of the identified metabolites. Acinetobacter sp. would have a potential application in bioremediation of cyprodinil-contaminated soil, and the strain might have important implications in detoxification and bioremediation of pyrimidine analogues.
研究领域:
环境微生物学
·
生物修复
·
农药降解
·
土壤科学
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PubMed
高影响因子
CHEMOSPHERE
·
2024
·
IF 8.1
Haoyang Liu,Yang Yu,Shengtao Jiang,Haimin Sun,Weixi Zhang,Jianmeng Chen,Dongzhi Chen
The efficient biodegradation of volatile chlorinated hydrocarbons using microbial fuel cells (MFCs) offers a feasible approach for purifying waste gas and alleviating energy crises. However, power generation is limited by poor pollutant biodegradation and slow electron transfer . The bifunctional bacterium Acinetobacter sp. HY-99C was screened and used to improve the performance of a conventional MFC. The inoculation of strain HY-99C into the conventional MFC promoted the formation of a compact biofilm with high metabolic activity and an enriched bifunctional genus ( Acinetobacter ), which resulted in the accelerated decomposition of chlorinated aromatic compounds into biodegradable organic acids. This led to efficient chlorobenzene removal and power generation from the MFC, with a chlorobenzene elimination capacity of 70.8 g m −3 h −1 and power density of 89.6 mW m −2 , which are improved over those of previously reported MFCs. This study provides novel insights into enhancing pollutant removal and power generation in MFCs.
研究领域:
环境科学
·
微生物学
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高影响因子
ENZYME AND MICROBIAL TECHNOLOGY
·
2025
·
IF 3.7
Jing Wu,Zhenggang Han,Pengrong Li,Jing Li,Yuanyuan Chen,Shangbo Ning,Hong-jun Chao,Xue-wang Gao,Dazhong Yan
Cyclohexylamine oxidase is a member of amine oxidases that catalyzes the conversion of cyclohexylamine to cyclohexanone. In our previous work, the enzymatic activity assay of cyclohexylamine oxidase CHAO YT-02 indicated that its specific activity towards cyclohexylamine of CHAO YT-02 was ten times higher than that of its homolog CHAO IH-35A . In this study, the crystal structure of CHAO YT-02 was determined by the molecular replacement method at a resolution of 1.49 Å. The atomic structure revealed that the amino acid residues Leu302, Trp70, Phe197, Phe349, and Tyr440 constitute the active center pocket of the enzyme. Amino acid residues Ile180, Leu181, and Trp332 separate the active center pocket and an intermediate pocket. Moreover, a molecular dynamics (MD) simulation and the calculation of the binding free energy were performed to predict substrate entry and product release from cyclohexylamine oxidases. Single-amino acid substitution mutants (W70A, I180A, L181A, I208A, F197A, L302A, W332A, F349A, and Y440A) of CHAO YT-02 were constructed to investigate the role of these amino acid residues in enzymatic properties and substrate specificity. The results indicated that both the amino acid residues in the active center pocket and gating the two pockets affected the activity or substrate specificity of CHAO YT-02 . This study on the structure and catalytic mechanism of cyclohexylamine oxidase is beneficial to eliminating toxic amine compounds in the environment.
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高影响因子
BIORESOURCE TECHNOLOGY
·
2020
·
IF 7.539
Zhe Dou,Guochao Xu,Ye Ni
A novel carboxylesterase Ac Est1 was identified from Acinetobacter sp. JNU9335 with high efficiency in the biosynthesis of chiral precursor of Edoxaban through kinetic resolution of methyl 3-cyclohexene-1-carboxylate (CHCM). Sequence analysis revealed Ac Est1 belongs to family IV of esterolytic enzymes and exhibits <40% identities with known carboxylesterases. The optimum pH and temperature of recombinant Ac Est1 are 8.0 and 40 °C. Substrate spectrum analysis indicated that Ac Est1 prefers substrates with short acyl and alcohol groups. Ac Est1 was highly active in the hydrolysis of CHCM with k cat of 1153 s −1 and displayed high substrate tolerance. As much as 2.0 M (280 g·L −1 ) CHCM could be enantioselectively hydrolyzed into ( S )-CHCM by merely 0.08 g·L −1 Ac Est1 with ee s of >99% ( S ) and substrate to catalyst ratio (S/C) of 3500 g·g −1 . These results indicate that the novel Ac Est1 is a promising biocatalyst in the synthesis of chiral carboxylic acids.
研究领域:
生物催化
·
酶学
·
药物化学
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PubMed
高影响因子
ENVIRONMENTAL POLLUTION
·
2023
·
IF 8.9
Edidiong Okokon Atakpa,Hanghai Zhou,Lijia Jiang,Dongdong Zhang,Yanhong Li,Wenjie Zhang,Chunfang Zhang
The widespread exploration and exploitation of crude oil has increased the prevalence of petroleum hydrocarbon pollution in the marine and coastal environment. Bioremediation of petroleum hydrocarbons using cell immobilization techniques is gaining increasing attention. In this study, the crude oil degradation performance of bacterial and fungal co-culture was optimized by entrapping both cells in sodium-alginate and polyvinyl alcohol composite beads. Results indicate that fungal cells remained active after entrapment and throughout the experiment, while bacterial cells were non-viable at the end of the experimental period in treatments with the bacterial-fungal ratio of 1:2. A remarkable decrease in surface tension from 72 mN/m to 36.51 mN/m was achieved in treatments with the bacterial-fungal ratio of 3:1. This resulted in a significant ( P < 0.05 ) total petroleum hydrocarbon (TPH) removal rate of 89.4%, and the highest degradation of n -alkanes fractions (from 2129.01 mg/L to 118.53 mg/L), compared to the other treatments. Whereas PAHs removal was highest in treatments with the most fungal abundance (from 980.96 μg/L to 177.3 μg/L). Furthermore, enzymes analysis test revealed that catalase had the most effect on microbial degradation of the target substrate, while protease had no significant impact on the degradation process. High expression of almA and PAH-RHDa genes was achieved in the co-culture treatments, which correlated significantly ( P < 0.05 ) with n -alkanes and PAHs removal, respectively. These results indicate that the application of immobilized bacterial and fungal cells in defined co-culture systems is an effective strategy for enhanced biodegradation of petroleum hydrocarbons in aqueous systems.
研究领域:
环境科学
·
微生物学
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高影响因子
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