SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
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IF 6.551
Jiahui Fan,Yangyang Jia,Dongdong Xu,Zhe Ye,Jiahang Zhou,Jionghao Huang,Yulong Fu,Chaofeng Shen
Significant microbial removal of highly chlorinated polychlorinated biphenyls (PCBs) requires the cooperation of anaerobic and aerobic bacteria. During the sequencing process of anaerobic dechlorination and aerobic degradation of PCBs, aerobic degrading bacteria have to undergo anaerobic stress. However, the survival strategy of aerobic degrading bacteria under anaerobic condition is not well-understood. In this study, the culturable cells of Rhodococcus biphenylivorans TG9 decreased from 10 8 CFU/mL to values below the detection limit after 60 days of anaerobic stress while the viable cells remained 10 5 –10 6 cells/mL, indicating that anaerobic condition induced TG9 entering into the viable but nonculturable (VBNC) state. Cell resuscitation was observed when oxygen was supplied further confirming the VBNC state of TG9. The results of single-cell Raman spectroscopy combined with heavy water indicated the significant decrease of metabolic activity after TG9 entering into the VBNC state. Additionally, the degradation ability of TG9 in the VBNC state was also significantly reduced, while it recovered after resuscitation. Our research proved that entering into the VBNC state is a survival strategy of TG9 under anaerobic conditions, and the limited culturability and degrading capacity could be overcome by resuscitation. The present study provides new insights for improving the remediation efficiency of PCBs contamination.
研究领域:
微生物学
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环境科学
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PubMed
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2018
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IF 1.712
Xiaoqiang Jia,Yun He,Lei Huang,Dawei Jiang,Wenyu Lu
The high-molecular weight polycyclic aromatic hydrocarbons (PAHs) pyrene and typical long chain alkane n -hexadecane are both difficult to degrade. In this study, n -hexadecane and pyrene degrading strain Rhodococcus sp. T1 was isolated from oil contaminated soil. Strain T1 could remove 90.81% n -hexadecane (2 vol%) and 42.79% pyrene (200 mg·L − 1 ) as a single carbon within 5 days, respectively. Comparatively, the degradation of pyrene increased to 60.63%, but the degradation of n -hexadecane decreased to 87.55% when these compounds were mixed. Additionally, identification and analysis of degradation metabolites of Rhodococcus sp. T1 in the above experiments showed that there were significant changes in alanine, methylamine, citric acid and heptadecanoic acid between sole and dual substrate degradation. The optimal conditions for degradation were then determined based on analysis of the pH, salinity, additional nutrient sources and liquid surface activity. Under the optimal conditions of pH 7.0, 35 °C, 0.5% NaCl, 5 mg·L − 1 of yeast extract and 90 mg·L − 1 of surfactant, the degradation increased in single or dual carbon sources. To our knowledge, this is the first study to discuss metabolite changes in Rhodococcus sp. T1 using sole substrate and dual substrate to enhance the long-chain alkanes and PAHs degradation potential.
研究领域:
环境微生物学
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生物修复
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生物化学
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高影响因子
BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2024
·Vol. 47
·期 3
·355-366
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IF 3.5
Duan Xiaoyan,Pi Qian,Tang Lei
Dyes in wastewater have adverse effects on the environment and human health. Dye-decolorizing peroxidase (DyP) is a promising biocatalyst to dyes degradation, but the decolorization rates varied greatly which influencing factors and mechanisms remain to be fully disclosed. To explore an effective decolorizing approach, we have studied a DyP from Rhodococcus jostii ( Rh DyPB) which was overexpressed in Escherichia coli to decolorize four kinds of dyes, Reactive blue 19, Eosin Y, Indigo carmine, and Malachite green. We found the decolorization rates of the dyes by purified Rh DyPB were all pH-dependent and the highest one was 94.4% of Malachite green at pH 6.0. ESI–MS analysis of intermediates in the decolorization process of Reactive blue 19 proved the degradation was due to peroxidase catalysis. Molecular docking predicated the interaction of Rh DyPB with dyes, and a radical transfer reaction. In addition, we performed decolorization of dyes with whole E. coli cell with and without expressing Rh DyPB. It was found that decolorization of dyes by E. coli cell was due to both cell absorption and degradation, and Rh DyPB expression improved the degradation rates towards Reactive blue 19, Indigo carmine and Malachite green. The effective decolorization of Malachite green and the successful application of whole DyP-overexpressed cells in dye decolorization is conducive to the bioremediation of dye-containing wastewaters by DyPs. Graphical abstract
研究领域:
环境生物技术
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酶催化
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生物修复
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蛋白质工程
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废水处理
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高影响因子
MARINE POLLUTION BULLETIN
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2026
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IF 4.9
Genxiu Li,Nan Meng,Jiaxin Zhang,Jiahui Liu,Wen Kuang,Jia Shi,Chao Chen,Jicheng Yu,Qiu Liu,Qiao Ma
A marine skatole-degrading consortium was enriched from sediment. • Rhodococcus sp. SJ-2 removed 100 mg/L skatole within 24 h. • SJ-2 maintained skatole removal across 0–45‰ NaCl. • 3-Methyloxindole was detected as an inducible transformation intermediate. • SJ-2 accelerated skatole removal in freshwater and marine microcosms. Skatole, primarily generated via the anaerobic metabolism of tryptophan, is a pervasive nitrogenous heterocyclic malodorant. While ubiquitous in various environments, its microbial remediation in saline ecosystems remains poorly documented. In this study, a skatole-degrading microbial consortium was enriched from marine sediments. High-throughput sequencing revealed distinct successional dynamics during domestication, with Pseudomonas becoming predominant (89.23%) and Rhodococcus persisting as a potential functional taxon (1.98%). An efficient isolate, Rhodococcus sp. SJ-2, was successfully obtained from the consortium. SJ-2 could completely remove 100 mg/L of skatole within 24 h in 2216E medium and 60 h in marine mineral culture medium, with optimal activity at 30–35 °C and pH 6.0–9.0. It also maintained skatole-removing activity across a broad salinity range of 0–45‰ NaCl. 3-Methyloxindole was identified as a detectable intermediate, and the enzymes involved in skatole degradation were inducible. Genomic analysis revealed a 5.77 Mb circular chromosome and two plasmids, but no previously reported skaA homologs, suggesting an as-yet-uncharacterized oxidative system. Bioaugmentation experiments in freshwater and marine sediment microcosms demonstrated that SJ-2 inoculation accelerated skatole removal, shortening the complete removal time to 6 h and 12 h, respectively. Amplicon sequencing showed that bioaugmentation was associated with an increased relative abundance of Rhodococcus and with predicted functional shifts related to aromatic compound degradation. These findings identify Rhodococcus sp. SJ-2 as a promising marine-derived candidate for skatole removal in saline odor-control settings and provide a useful foundation for future studies on the molecular basis of skatole catabolism. Download: Download high-res image (156KB) Download: Download full-size image
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高影响因子
JACS Au
·
2024
·
IF 8.5
Yaoyun Wu,Yaozhong Cui,Wei Song,Wanqing Wei,Zhizhen He,Jinyang Tao,Dejing Yin,Xiulai Chen,Cong Gao,Jia Liu,Liming Liu,Jing Wu
l-Amino acid oxidase (LAAO) is an important biocatalyst used for synthesizing α-keto acids. LAAO from Rhodococcus opacus (RoLAAO) has a broad substrate spectrum; however, its low total turnover number limits its industrial use. To overcome this, we aimed to employ crystal structure-guided density functional theory calculations and molecular dynamic simulations to investigate the catalytic mechanism. Two key steps were identified: S → [TS1] in step 1 and Int1 → [TS2] in step 2. We reprogrammed the transition states [TS1] and [TS2] to reduce the identified energy barrier and obtain a RoLAAO variant capable of catalyzing 19 kinds of l-amino acids to the corresponding high-value α-keto acids with a high total turnover number, yield (≥95.1 g/L), conversion rate (≥95%), and space-time yields ≥142.7 g/L/d in 12–24 h, in a 5 L reactor. Our results indicated the promising potential of the developed RoLAAO variant for use in the industrial production of α-keto acids while providing a potential catalytic-mechanism-guided protein design strategy to achieve the desired physical and catalytic properties of enzymes.
研究领域:
生物催化
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酶工程
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计算化学
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蛋白质工程
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PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2024
·
IF 8.2
Chu-Qi Feng,Xiao-Qian Chen,Qing-Song Huang,Xiao-Min Zhao,Sheng Chen,Ke-Wei Xu,Jing Wu,Zheng-Fei Yan
Poly(ethylene terephthalate) (PET) is a widely used plastic, but its improper disposal has caused serious environmental pollution. The development of bioconversion for PET waste into high-value chemicals has gained significant attention as an innovative solution. In this study, a novel guided screening strategy involving mixed-bacteria fermentation and partitioned purification (MBF) was proposed to first successful isolate Rhodococcus jostii LETBE 8896, a strain capable of naturally producing 4 μg/L of lycopene from PET hydrolysate. Transcriptomic analysis identified the methylerythritol 4-phosphate (MEP) pathway as key to lycopene biosynthesis, with IspG identified as a critical regulatory enzyme. R. jostii with ispG overexpression enhanced lycopene production, with 819 μg/L in the simulated PET hydrolysate and 650 μg/L in the PET hydrolysate. Additionally, the use of butylated hydroxytoluene (BHT) as an antioxidant significantly improved lycopene production at 1 L scale level, achieving a maximum yield of 1865 μg/L with a molar conversion rate of 50.36 % from the PET hydrolysate, the highest reported for PET hydrolysate to date. These findings highlight the dual potential of R. jostii as a chassis strain for high-value chemical production and as a sustainable solution for PET upcycling. This study provides a novel approach to plastic waste management, contributing to the circular economy and global sustainability goals.
研究领域:
环境科学
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微生物学
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生物化学
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PubMed
高影响因子
Life-Basel
·
2026
·Vol. 16
·期 2
·
IF 3.9
Xinyuan Wei,Haoyu Wang,Rui Li,Shengmin Liu,Hongyan Zuo,Qing Hu,Xuliang Zhuang,Zhihui Bai
Petroleum contamination poses a serious threat to human health and ecosystems worldwide, and microbially driven natural attenuation is an effective approach for accelerating hydrocarbon removal. Species of the genusRhodococcusare recognized for their ability to degrade long chain petroleum hydrocarbons. However, their physiological traits and degradation mechanisms under alkaline conditions remain insufficiently understood. In this study, soil samples were collected from the Dagang oilfield in Tianjin, China, andRhodococcussp. A17 was isolated as an active indigenous strain for genomic and physiological characterization under high pH petroleum degradation conditions. The results showed that strain A17 grew optimally at 30 °C, pH 9.0, and 2% salinity. Petroleum hydrocarbon degradation reached 67.8% within 72 h, with a degradation half life of 34.2 h. Genome sequencing identified 18 oxygenase related genes involved in alkane degradation, includingalkB, cytochrome P450 monooxygenases, and the long chain alkane monooxygenaseladA, together with four antibiotic resistance genes. Metabolite analysis suggested that alkane degradation might proceed via terminal and subterminal oxidation pathways. Overall, these findings indicate thatRhodococcussp. A17 exhibits multiple adaptive traits that support its potential application in the bioremediation of petroleum contaminated alkaline environments.
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高影响因子
ENVIRONMENTAL RESEARCH
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2023
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IF 8.3
Ni-Hong Yao,Ya-Nan Du,Jia-Xi Xiong,Ying Xiao,Hang-Hang He,Ze-Feng Xie,Duo Huang,Qi Song,Jing Chen,Dazhong Yan,Hong-Jun Chao
The compound 3,5-xylenol is an essential precursor used in pesticides and industrial intermediate in the disinfectants and preservatives industry. Its widespread application makes it an important source of pollution. Microbial bioremediation is more environmentally friendly than the physicochemical treatment process for removing alkylphenols from a polluted environment. However, the 3,5-xylenol-degrading bacteria is unavailable, and its degradation mechanism remains unclear. Here, a 3,5-xylenol-metabolizing bacterial strain, designated Rhodococcus sp. CHJ602, was isolated using 3,5-xylenol as the sole source of carbon and energy from a wastewater treatment factory. Results showed that strain CHJ602 maintained a high 3,5-xylenol-degrading performance under the conditions of 30.15 °C and pH 7.37. The pathway involved in 3,5-xylenol degradation by strain CHJ602 must be induced by 3,5-xylenol. Based on the identification of intermediate metabolites and enzyme activities , this bacterium could oxidize 3,5-xylenol by a novel metabolic pathway. One methyl oxidation converted 3,5-xylenol to 3-hydroxymethyl-5-methylphenol, 3-hydroxy-5-methyl benzaldehyde, and 3-hydroxy-5-methylbenzoate. After that, another methyl oxidation is converted to 5-hydroxyisophthalicate, which is metabolized by the protocatechuate pathway. It is catalyzed by a series of enzymes in strain CHJ602. In addition, toxicity bioassay result indicates that 3,5-xylenol is toxic to zebrafish and Rhodococcus sp. CHJ602 could eliminate 3,5-xylenol in water to protect zebrafish from its toxicity. The results provide insights into the bioremediation of wastewater contaminated 3,5-xylenol.
研究领域:
环境科学
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微生物学
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DOI
PubMed
高影响因子
Journal of Environmental Sciences
·
2016
·
IF 2.208
Xingdu Chen,Chengjian Yang,Weiwei Wang,Bizhou Ge,Jun Zhang,Yucan Liu,Yaping Nan
The biodegradation characteristic and potential metabolic pathway for removal of environmental N,N-dimethylacetamide (DMAC) by Rhodococcus sp. strain B83 was studied. Rhodococcus sp. strain B83 was isolated from the rhizosphere of a pagoda tree and proved capable of utilizing DMAC as sole source of carbon and nitrogen. Batch culture studies showed that strain B83 could tolerate up to 25 g/L DMAC and showed distinct growth on possible catabolic intermediates except for acetate. The nitrogen balance analysis revealed that approximately 71% of the initial nitrogen was converted to organic nitrogen. DMAC degradation has led to accumulation of acetate and organic nitrogen, meanwhile traces of nitrate and ammonia was build-up but without nitrite. The growth of strain B83 could be inhibited by adding exogenous acetate. By means of the assay of enzymatic degradation of DMAC, several catabolic intermediates at different intervals were observed and identified. Based on the results obtained from culture solution and enzymatic degradation assay, a detailed pathway is proposed for DMAC biodegradation.
研究领域:
环境微生物学
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生物修复
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生物降解
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DOI
PubMed
高影响因子
BIOTECHNOLOGY LETTERS
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2013
·Vol. 36
·期 2
·341-347
·
IF 1.853
He Yu-Cai,Wu Ya-Dong,Pan Xue-He,Ma Cui-Luan
The nitrilase from Rhodococcus sp. CCZU10-1 catalyses the hydrolysis of dinitriles to acids without the formation of amides and cyanocarboxylic acids. It was induced by benzonitrile and its analogues (tetrachloroterephthalonitrile > ε-caprolactam > benzonitrile > phenylacetonitrile), and had activity towards aromatic nitriles (terephthalonitrile > tetrachloroterephthalonitrile > isophthalonitrile > tetrachloroisophthalonitrile > tetrafluoroterephthalonitrile > benzonitrile). After the optimization, the highest nitrilase induction [311 U/(g DCW)] was achieved with tetrachloroterephthalonitrile (1 mM) in the medium after 24 h at 30 °C after optimum enzyme activity was at pH 6.8 and at 30 °C. Efficient biocatalyst recycling was achieved by cell immobilization in calcium alginate, with a product-to-biocatalyst ratios of 776 g terephthalic acid/g DCW and 630 g isophthalic acid/g DCW.
研究领域:
生物化学
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生物催化
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微生物生物技术
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工业微生物学
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绿色化学
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DOI
高影响因子
INTERNATIONAL BIODETERIORATION & BIODEGRADATION
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2026
·
IF 4.4
Fuyu Song,Jiaxi Liu,Qi Wu,Aiqin Diao,Yinhu Jiang,Xin Yan,Na Li,Jian He,Jiguo Qiu
An efficient Rhodococcus sp. YQ-4 strain degraded 98% of 2-ABT within 24 h. • A new intermediate metabolite (2-hydroxybenzothiazole) was identified. • A novel 2-ABT biotransformation pathway was proposed. • Biodegradation of 2-ABT was a detoxification process. 2-Aminobenzothiazole (2-ABT), a representative heterocyclic compound originating from tire wear particles, was widely detected in diverse environmental matrices. Due to its persistence and potential toxicity, the removal of 2-ABT from contaminated environments has become an increasing environmental concern. However, studies on the efficient biodegradation of 2-ABT by pure cultures remain limited. In this study, the abundance of Rhodococcus increased significantly following enrichment and acclimation. Subsequently, a 2-ABT-degrading pure culture, designated Rhodococcus sp. YQ-4, was isolated. Under the optimal conditions of pH 7.0, 1% NaCl, and 30 °C, strain YQ-4 achieved a removal rate of 98% for 50 μM 2-ABT within 24 h. A key metabolic intermediate, 2-hydroxybenzothiazole (2-OBT), was identified by liquid chromatography-time-of-flight mass spectrometry (LC-TOF-MS). Based on these results, a possible initial biotransformation pathway involving deamination and hydroxylation at the C2 position of the thiazole ring was proposed. Furthermore, toxicity bioassays involving the green alga Chlamydomonas ellipsoidea and mung bean ( Vigna radiata ) demonstrated that the biodegradation of 2-ABT by strain YQ-4 significantly alleviated its phytotoxicity, thereby restoring the growth and physiological vigor of the test species. Collectively, this study provided a novel bacterial resource for the bioremediation of 2-ABT-contaminated environments and offered new insights into the catabolic pathway associated with emerging pollutants.
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高影响因子
Water Research X
·
2026
·
IF 7
Jiahui Fan,Dongdong Xu,Zhiyao Wang,Yulong Fu,Xiaomei Su,Shihu Hu,Chaofeng Shen
Adverse conditions in water treatment system can induce bacteria into a viable but non-culturable (VBNC) state. This enables pathogens to evade detection during disinfection, and affect functional bacteria crucial for pollutants removal. However, the mechanisms underlying VBNC induction remain poorly understood. Here, we investigated Rhodococcus biphenylivorans TG9, a polychlorinated biphenyl (PCB)-degrading bacterium, under prolonged acid stress (pH 4). After 40 days, TG9 entered the VBNC state, resulting in a sharp decline in pollutants degradation efficiency due to reduced substrate transport capacity and enzymes activity. Under continuous acid stress, TG9 prioritized energy for maintaining intracellular pH homeostasis, at the expense of catabolic and anabolic functions. Such an energy trade-off facilitated VBNC as a surviving strategy, enabling the preservation of viable cells for potential resuscitation. However, prolonged acid stress depleted intracellular energy below a critical threshold, leading to an irreversible transition to a non-resuscitable state. These findings demonstrate the vital role of energy metabolism in bacterial stress responses, and suggest that manipulating energy availability may help prevent bacterial dormancy or reactivate dormant cells in engineered water systems.
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高影响因子
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