BIOTECHNOLOGY LETTERS
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2014
·Vol. 37
·期 1
·183-188
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IF 1.736
He Yu-Cai,Tao Zhi-Cheng,Zhang Dan-Ping,Yang Zhen-Xing,Gao Shan,Ma Cui-Luan
Rhodococcus sp. CGMCC 4911 transformed 1,3-propanediol cyclic sulfate (1,3-PDS) and its derivatives into corresponding diols. Ethylene sulfate, glycol sulfide, 1,3-PDS, and 1,2-propanediol cyclic sulfate were effectively hydrolyzed with growing cells. ( R )-1,2-Propanediol (>99 % e.e. ) was obtained at 44 % yield with growing cells. Glycol sulfide, ethylene sulfate, and 1,3-PDS were converted into the corresponding diols at 94.6, 96.3, and 98.3 %, respectively. Optimal reaction conditions with lyophilized resting cells were 30 °C, pH 7.5, and cell dosage 17.9 mg cell dry wt/ml. 1,3-Propanediol was obtained from 50 mM 1,3-PDS at 97.2 % yield by lyophilized cells after 16 h. Lyophilized cells were entrapped in calcium alginate with a half-life of 263 h at 30 °C, and the total operational time of the immobilized biocatalysts could reach over 192 h with a high conversion rate.
研究领域:
微生物学
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生物催化
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高影响因子
BIORESOURCE TECHNOLOGY
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2024
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IF 9.7
Juan Huang,Alei Zhang,Qi Yang,Yajun Ding,Zhongliang Xiao
The explosive and biorefractory nature of nitrocellulose (NC) poses major risks to both humans and the environment. Expanding the range of microorganisms capable of degrading NC is essential, though the most effective known microorganisms, Desulfovibrio genera and Fusarium solani , achieve degradation rates of 5%-25%. Here, a novel strain, Rhodococcus pyridinivorans LZ1 was isolated, demonstrating the ability to degrade NC, with its growth potentially enhanced by the presence of NC. The degradation process was monitored by assessing changes in nitrate, nitrite, and ammonium. Notably, the –OH strength of NC increased over time, whereas the energetic functional groups (–NO 2 and O-NO 2 ) diminished. Furthermore, the presence of NC enhanced nitrate esterase activity 1–2-fold, indicating that ammonification was the primary pathway for NC biodegradation. By converting the nitrate ester of NC into hydroxyl, R. pyridinivorans LZ1 mitigates the harmful effects of NC, offering a promising approach for the treatment of NC waste and wastewater.
研究领域:
微生物学
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环境科学
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生物化学
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PubMed
高影响因子
Royal Society Open Science
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2021
·Vol. 8
·期 12
·
IF 2.963
Xiaolei Ma,Duomo Duan,Xunliang Wang,Junrui Cao,Jinquan Qiu,Baolong Xie
Alkali-surfactant-polymer flooding technology is widely employed to extract crude oil to enhance its production. The bacterial strain Rhodococcus erythropolis SY095 has shown high degradation activity of alkane of crude oil. In the past, many treatment strategies have been implemented to reduce oil concentration in wastewater. Previous studies mainly focused on the extracellular products of Erythrococcus rather than its degradation properties. In the current study, we designed an immobilization method to modify the surface of R. erythropolis SY095 with functional Fe3O4 nanoparticles (NPs) for biodegradation of crude oil and separation of the immobilized bacteria after degradation. We characterize the synthesized NPs through various methods, including scanning electron microscope energy-dispersive spectrometer, Fourier transform infrared spectroscopy, X-ray diffraction (XRD) and a vibrating sample magnetometer. We found that the size of the synthesized NPs was approximately 100 nm. Our results showed that R. erythropolis SY095 was successfully coated with functional magnetic NPs (MNPs) that could be easily separated from the solution via the application of an external magnetic field. The coated cells had a high tolerance for heavy metals. Our findings demonstrated that the immobilization of MNPs to bacterial surfaces is a promising approach for the degradation of crude oil.
研究领域:
环境科学
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微生物学
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PubMed
高影响因子
Biointerphases
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2022
·Vol. 17
·期 6
·
IF 1.916
Wang Li,Cui Baocheng,Qiu Keyuan,Huang Jiao,Liang Changhai
Nitrile hydratase (NHase, EC 4.2.1.84) is an excellent biocatalyst that catalyzes the hydration of nitrile substances to their corresponding amides. Given its catalytic specificity and eco-friendliness, NHase has extensive applications in the chemical, pharmaceutical, and cosmetic industries. To improve the affinity between Rhodococcus erythropolis CCM2595-derived NHase ( Re NHase) and adiponitrile, this study used a semirational design to improve the efficiency of Re NHase in catalyzing the generation of 5-cyanopentanamide from adiponitrile. Enzyme kinetics analysis showed that Km of the mutant Re NHase B:G196Y was 3.265 mmol l −1 , which was lower than that of the wild-type NHase. The affinity of the mutant Re NHase B:G196Y to adiponitrile was increased by 36.35%, and the efficiency of the mutant Re NHase B:G196Y in catalyzing adiponitrile to 5-cyanopentamide was increased by 10.11%. The analysis of the enzyme-substrate interaction showed that the hydrogen bond length of the mutant Re NHase B:G196Y to adiponitrile was shortened by 0.59 Å, which enhanced the interaction between the mutant and adiponitrile and, thereby, increased the substrate affinity. Similarly, the structural analysis showed that the amino acid flexibility near the mutation site of Re NHase B:G196Y was increased, which enhanced the binding force between the enzyme and adiponitrile. Our work may provide a new theoretical basis for the modification of substrate affinity of NHase and increase the possibility of industrial applications of the enzyme.
研究领域:
生物化学
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工业酶学
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PubMed
高影响因子
GEOMICROBIOLOGY JOURNAL
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2020
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IF 1.989
Xin Hu,Yue Qiao,Long-Qiang Chen,Jian-Fei Du,Yue-Yue Fu,Si Wu,Lei Huang
The demand to repair areas contaminated with hydrocarbon products has led to the development of new technologies for the treatment of contaminants in an unconventional method, that is, no physical or chemical methods are used. Biosurfactants are amphiphilic biomolecules produced by microorganisms that can be used in environments contaminated by petroleum products due to their unexceptionable tensile properties. Petroleum degrading strain Rhodococcus erythropolis HX-2 was found to be an effective producer of biosurfactants. The resulting biosurfactant (named NK) exhibits high physicochemical properties in terms of surface activity. It is capable of reducing surface tension from 54.99 to 28.89 mN/m and critical micelle concentration (CMC) is 100 mg/L. NK was found to be a substitute for chemically synthesized surfactants because of its higher solubilization efficiency for petroleum and polycyclic aromatic hydrocarbons, superior to SDS, Tween 80, Triton X-100 and Rhamnolipid (a wide used biosurfactant). In addition, it exhibits favorable emulsion stability over a wide range of pH (3–10), temperature (20–100 °C) and salinity ranges (5–20 g/L). It was found that the addition of biosurfactant can improve the efficiency of petroleum degradation, therefore it has potential applications in bioremediation.HighlightsRhodococcus erythropolis HX-2 is an effective petroleum degrading strain.HX-2 is a potential source of biosurfactant production.The biosurfactant NK reduces surface tension and exhibits high emulsification activity.The biosurfactant NK is effective over a wide range of temperatures, pH and salinity.The biosurfactant NK shows high solubilization efficiency for petroleum as well as polycyclic aromatic hydrocarbons.
研究领域:
环境科学
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微生物学
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高影响因子
Communications Biology
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2023
·Vol. 6
·期 1
·1-13
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IF 5.9
Guo Wenbin,Duan Jingjing,Shi Zhengguang,Yu Xue,Shao Zongze
Evidence for microbial biodegradation of polyethylene terephthalate (PET) has been reported, but little is known about the PET biodegradation process and molecular mechanism by marine microorganisms. Here, we show the biodegradation of PET by the membrane-anchored PET esterase from the marine bacterium Rhodococcus pyridinivorans P23, elucidate the properties of this enzyme, and propose the PET biodegradation by this strain in biofilm. We identify the PET-degrading enzyme dubbed PET esterase through activity tracking. In addition to depolymerizing PET, it hydrolyzes MHET into TPA under acid conditions. We prove that it is a low and constitutively transcribed, membrane-anchored protein displayed on the cell surface. Furthermore, we also investigate the microbial groups possessing PET esterase coupled with the TPA degradation pathway, mainly in the phyla Proteobacteria and Actinobacteriota . Clarification of the microbial PET biodegradation in the marine environment will contribute to the understanding of bioremediation of marine PET pollution.
研究领域:
环境微生物学
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生物技术
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海洋污染
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高影响因子
BIOTECHNOLOGY AND BIOPROCESS ENGINEERING
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2020
·Vol. 25
·期 4
·589-598
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IF 2.213
He Jinjia,Chen Yi,Dai Luyao,Yao Jiachao,Mei Yu,Hrynsphan Dzmitry,Tatsiana Savitskaya,Chen Jun
Acrylic acid is used in various industrial applications but inflicts harm to human health and causes environmental pollution. A new bacterium, identified as Rhodococcus ruber JJ-3, was isolated, which can degrade high concentrations of acrylic acid rapidly and completely. Experimental results showed that the strain can achieve complete degradation of 1000 mg·L −1 acrylic acid in 11 h under the following conditions: pH 7, temperature 35°C, and inoculation quantity 15%. A high concentration of acrylic acid (2000 mg·L −1 ) can be completely removed in 28 h. According to the Monod model, the maximum specific degradation rate ( v max ) and half saturation rate constant ( K S ) of the strain were 0.85 h −1 and 101.83 mg·L −1 , respectively. The results of carbon balance revealed that 54.6% carbon was assimilated by R. ruber JJ-3 as biomass, and 43.0% carbon was mineralized into CO 2 . Furthermore, glycerol and lactic acid were measured as intermediates, and the possible degradation pathway was proposed during the biodegradation of acrylic acid. These results suggested that R. ruber JJ-3 completely degrades acrylic acid and might have a potential environmental implication in the purification of acrylic acid-contaminated environments.
研究领域:
微生物学
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环境科学
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生物化学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2014
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IF 4.331
Zhixing He,Chengzhen Niu,Zhenmei Lu
The bacterial strain DP-2, identified as Rhodococcus ruber , is able to effectively degrade di-n-butyl phthalate (DBP) and phenol. Degradation kinetics of DBP and phenol at different initial concentrations revealed DBP and phenol degradation to fit modified first-order models. The half-life of DBP degradation ranged from 15.81 to 27.75 h and phenol degradation from 14.52 to 45.52 h under the initial concentrations of 600–1200 mg/L. When strain DP-2 was cultured with a mixture of DBP (800 mg/L) and phenol (700 mg/L), DBP degradation rate was found to be only slightly influenced; however, phthalic acid (PA) accumulated, and phenol degradation was clearly inhibited during synchronous degradation. Transcriptional levels of degradation genes, phenol hydroxylase ( pheu ) and phthalate 3,4-dioxygenase ( pht ), decreased significantly more during synchronous degradation than during individual degradation. Quantitative estimation of individual or synchronous degradation kinetics is essential to manage mixed hazardous compounds through biodegradation in industrial waste disposal.
研究领域:
环境科学
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微生物学
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PubMed
高影响因子
International Journal of Genomics
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2020
·
IF 2.414
Kejian Tian,Fanxing Meng,Qi Meng,Yan Gao,Lili Zhang,Le Wang,Yuqing Wang,Xue Li,Hongliang Huo
Estrogen contamination is recognized as one of the most serious environmental problems, causing widespread concern worldwide. Environmental estrogens are mainly derived from human and vertebrate excretion, drugs, and agricultural activities. The use of microorganisms is currently the most economical and effective method for biodegradation of environmental estrogens. Rhodococcus equi DSSKP-R-001 (R-001) has strong estrogen-degrading capabilities. Our study indicated that R-001 can use different types of estrogen as its sole carbon source for growth and metabolism, with final degradation rates above 90%. Transcriptome analysis showed that 720 (E1), 983 (E2), and 845 (EE2) genes were significantly upregulated in the estrogen-treated group compared with the control group, and 270 differentially expressed genes (DEGs) were upregulated across all treatment groups. These DEGs included ABC transporters; estrogen-degrading genes, including those that perform initial oxidation and dehydrogenation reactions and those that further degrade the resulting substrates into small molecules; and metabolism genes that complete the intracellular transformation and utilization of estrogen metabolites through biological processes such as amino acid metabolism, lipid metabolism, carbohydrate metabolism, and the tricarboxylic acid cycle. In summary, the biodegradation of estrogens is coordinated by a metabolic network of estrogen-degrading enzymes, transporters, metabolic enzymes, and other coenzymes. In this study, the metabolic mechanisms by which Rhodococcus equi R-001 degrades various estrogens were analyzed for the first time. A new pollutant metabolism system is outlined, providing a starting point for the construction of engineered estrogen-degrading bacteria.
研究领域:
微生物学
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环境科学
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基因组学
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高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2021
·
IF 10.588
Junhuan Wang,Thet Su Hlaing,May Thet Nwe,Mar Mar Aung,Chao Ren,Wei Wu,Yanchun Yan
In this study, the biodegradation towards aryl organophosphate flame retardants (aryl-OPFRs) was investigated by the Rhodococcus-Sphingopyxis consortium, mixture of strain Rhodococcus sp. YC-JH2 and Sphingopyxis sp. YC-JH3. The optimal ratio between the two composition strains was determined as 1:1. Under the optimum condition (pH 8, 35 °C and 0% salinity), the consortium could utilize aryl-OPFRs as sole carbon source and degrade them rapidly with half-life of 4.53, 21.11 and 23.0 h for triphenyl phosphate (TPhP), tricresyl phosphate (TCrP) and 2-ethylhexyl diphenyl phosphate (EHDPP) respectively. The consortium maintained high degrading efficiency under a wide of range of pH (6–10), temperature (20–40 °C) and salinity (0–6%). Besides, the consortium could rapidly degrade high concentration of TPhP and no inhibitory effect towards degradation speed was observed up to 500 mg/L. The effect of metal ions and surfactants was estimated. Most metal ions exhibited significant inhibition, except Zn 2+ and Pb 2+ , which showed no effect or slight promotion. Ionic surfactants could severely reduce the degrading capacity, while nonionic surfactants showed no effect. With abundant inoculation of the consortium, mineralization higher than 75% could be achieved within a week. This study provides efficient microorganisms for bioremediation of aryl-OPFRs contamination.
研究领域:
环境科学
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微生物学
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PubMed
高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
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2021
·
IF 6.291
Jing Liu,Ai-Ning Zhang,Yong-Jun Liu,Zhe Liu,Yu Liu,Xi-Jun Wu
A slow degradation rate and low transformation efficiency are the main problems in the biodegradation of polycyclic aromatic hydrocarbons (PAHs). This study selected pyrene as the target PAH to investigate the effect of ferrous ion and ferric ion on pyrene degradation. The driving effect and mechanism, including the interaction between pyrene and iron ions and the bacterial physiological response during the biodegradation process by Rhodococcus ruber strain L9, were investigated. The results showed that iron ions did not enhance bacterial growth but improved bacteria’s pyrene removal capacity, contributing to the total efficiency of pyrene biodegradation. The process started with an initial formation of “cation-π” between Fe (III) and pyrene, which subsequently drove the pyrene removal process and accelerated the bacterial metabolic process. Moreover, a significant increase in the protein concentration, catechol dioxygenase (C12O and C23O) activities, and intracellular protein regulation in crude enzyme solution indicate a positive response of the bacteria during the iron ion-enhanced pyrene degradation process.
研究领域:
环境生物学
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微生物学
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PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2023
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IF 13.6
Shu-Ting Zhang,Tao Li,Shi-Kai Deng,Jim C. Spain,Ning-Yi Zhou
Nitroanisoles are used widely as synthetic intermediates and explosives. Although bacteria have been reported to degrade 4-nitroanisole (4NA) under aerobic conditions , the key enzymes and the catalytic mechanism have remained elusive. Rhodococcus sp. strain JS3073 was isolated for its ability to grow on 4NA as the sole carbon and energy source. In this study, whole cell biotransformation experiments indicated that 4NA degradation is initiated by O -demethylation to form 4-nitrophenol (PNP), which undergoes subsequent degradation by a previously established pathway involving formation of 1,2,4-benzenetriol and release of nitrite. Based on comparative transcriptomics and heterologous expression, a novel three-component cytochrome P450 system encoded by pnaABC initiates the O -demethylation of 4NA to yield formaldehyde and PNP. The pnaABC genes encode a phthalate dioxygenase type reductase (PnaA), a cytochrome P450 monooxygenase (PnaB), and an EthD family protein (PnaC) with putative function similar to ferredoxins. This unusual P450 system also has a broad substrate specificity for nitroanisole derivatives. Sequence analysis of PnaAB revealed high identity with multiple self-sufficient P450s of the CYP116B subfamily. The findings revealed the molecular basis of the catabolic pathway for 4NA initiated by an unusual O -demethylase PnaABC and extends the understanding of the diversity among P450s and their electron transport chains.
研究领域:
微生物学
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环境科学
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分子生物学
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PubMed
高影响因子
危险品化学品经营许可证（带存储）