Fermentation-Basel
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2023
·Vol. 9
·期 2
·133
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IF 3.7
Peng Cheng,Muhammad Usman,Muhammad Arslan,Huanqing Sun,Li Zhou,Mohamed Gamal El-Din
A Gram-positive exoelectrogenRhodococcus pyridinivoranssp. strain HR-1 was cultivated from leachate-fed microbial fuel cell (MFC) to study the biodegradation effect of pyridine. In the comparison with mixed cultured MFC, HR-1 presented a remarkable electrical capacity with a maximum output of 4.33 W/m3under 30 °C in neutral anolyte with 1 g/L acetate as a substrate. Further, HR-1 demonstrated the environmental resistance as a Gram-positive strain. Microbial metabolism was evident at pH between 5–9 and temperature in the range of 20–40 °C, whereas optimal condition for pyridine degradation was observed at 30 °C. This is the first study reporting the degradation of pyridine in the bio-electrochemical system that achieved a 42% ± 5% degradation rate in a full operation cycle at 2 g/L of the concentration. Considering the nonnegligible internal resistance of HR-1-inoculated MFC, trehalose lipid was also introduced as a bio-surfactant to reduce the charge transfer obstacle between the microbes and the electrodes. The surface morphology illustrated that the strain had a plump shape with a high specific area. Accordingly, bio-surfactant addition promoted the anode biomass (1.2 ± 0.1 mg/cm2to 1.7 ± 0.2 mg/cm2) and achieved a higher degradation rate (68% ± 4%). The feasibility of electrochemical disposal on pyridine and eminent adaptability of strain sp. HR-1 as a Gram-positive exoelectrogen makes MFC a practical approach for real application.Keywords:microbial fuel cells;gram-positive exoelectrogen;pyridine;trehalose lipid;Rhodococcus pyridinivorans
研究领域:
环境科学
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微生物学
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DOI
高影响因子
Frontiers in Microbiology
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2024
·
IF 4
Xie Junjie,Yin Doudou,Ou Junchao,Lu Bo,Liao Siming,Yang Dengfeng,Zhang Hongyan,Shen Naikun
Introduction: Chitin, abundant in marine environments, presents significant challenges in terms of transformation and utilization. A strain, T22.7.1T, with notable chitin deacetylation capabilities, was isolated from the rhizosphere of Acanthus ebracteatus in the North Sea of China. Comparative 16S rDNA sequence analysis showed that the new isolate had the highest sequence similarity (99.79%) with Rhodococcus indonesiensis CSLK01-03T, followed by R. ruber DSM 43338T, R. electrodiphilus JC435T, and R. aetherivorans 10bc312T (98.97%, 98.81%, and 98.83%, respectively). Subsequent genome sequencing and phylogenetic analysis confirmed that strain T22.7.1T belongs to the R. indonesiensis species. However, additional taxonomic characterization identified strain T22.7.1T as a novel type strain of R. indonesiensis distinct from CSLK01-03T.Methods: This study refines the taxonomic description of R. indonesiensis and investigates its application in converting chitin into chitosan. The chitin deacetylase (RiCDA) activity of strain T22.7.1T was optimized, and the enzyme was isolated and purified from the fermentation products.Results: Through optimization, the RiCDA activity of strain T22.7.1T reached 287.02 U/mL, which is 34.88 times greater than the original enzyme’s activity (8.0 U/mL). The natural CDA enzyme was purified with a purification factor of 31.83, and the specific activity of the enzyme solution reached 1200.33 U/mg. RiCDA exhibited good pH and temperature adaptability and stability, along with a wide range of substrate adaptabilities, effectively deacetylating chitin, chitooligosaccharides, N-acetylglucosamine, and other substrates.Discussion: Product analysis revealed that RiCDA treatment increased the deacetylation degree (DD) of natural chitin to 83%, surpassing that of commercial chitosan. Therefore, RiCDA demonstrates significant potential as an efficient deacetylation tool for natural chitin and chitooligosaccharides, highlighting its applicability in the biorefining of natural polysaccharides.
研究领域:
微生物学
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生物技术
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酶学
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DOI
PubMed
高影响因子
FOOD CHEMISTRY
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2017
·
IF 4.529
Yashu Chen,Bijun Xie,Jifang Yang,Jigang Chen,Zhida Sun
Rhodococcus sp. B7740 is a newfound bacterium which was isolated from 25 m deep seawater in the arctic. In this paper, Rhodococcus sp. B7740 was firstly discovered to produce abundant natural isoprenoids, including ubiquinone-4(UQ-4), 13 kinds of menaquinones, three rare aromatic carotenoids and more than one common carotenoid. These compounds were identified by UV–Visible, HPLC-APCI-MS/MS and HRMS spectra. Results demonstrated that Rhodococcus sp. B7740 might be a worthy source of natural isoprenoids especially for scarce aromatic carotenoids. Among them, isorenieratene with 528.3762 Da (calculated for 528.3756 Da, error: 1.1 ppm), a carotenoid with aromatic ring, was purified by HSCCC. The stability of isorenieratene under the mimical gastric conditions was measured compared with common dietary carotenoids, β-carotene and lutein. Unlike β-carotene and lutein, isorenieratene exhibited rather stable in the presence of free iron or heme iron. Its high retention rate in gastrointestinal tract after ingestion indicates the benefits for health.
研究领域:
微生物学
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营养学
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DOI
PubMed
高影响因子
CHEMOSPHERE
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2024
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IF 8.1
Hong-Peng Shi,Ying-Hao Zhao,Mei-Lin Zheng,Cheng-Yan Gong,Lei Yan,Ying Liu,Yong-Ming Luo,Zhi-Pei Liu
The performance of bacterial strains in executing degradative functions under the coexistence of heavy metals/heavy metal-like elements and organic contaminants is understudied. In this study, we isolated a fluorene-degrading bacterium, highly arsenic-resistant, designated as strain 2021, from contaminated soil at the abandoned site of an old coking plant. It was identified as a member of the genus Rhodococcus sp. strain 2021 exhibited efficient fluorene-degrading ability under optimal conditions of 400 mg/L fluorene, 30 °C, pH 7.0, and 250 mg/L trivalent arsenic. It was noted that the addition of arsenic could promote the growth of strain 2021 and improve the degradation of fluorene – a phenomenon that has not been described yet. The results further indicated that strain 2021 can oxidize As 3+ to As 5+ ; here, approximately 13.1% of As 3+ was converted to As 5+ after aerobic cultivation for 8 days at 30 °C. The addition of arsenic could greatly up-regulate the expression of arsR / A / B / C / D and pcaG / H gene clusters involved in arsenic resistance and aromatic hydrocarbon degradation; it also aided in maintaining the continuously high expression of cstA that codes for carbon starvation protein and prmA / B that codes for monooxygenase. These results suggest that strain 2021 holds great potential for the bioremediation of environments contaminated by a combination of arsenic and polycyclic aromatic hydrocarbons. This study provides new insights into the interactions among microbes, as well as inorganic and organic pollutants.
研究领域:
环境微生物学
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生物修复
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毒理学
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分子生物学
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产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
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2022
·
IF 11.889
Peng Cheng,Yingchuan Zhang,Nianfang Ma,Lining Wang,Liqun Jiang,Zhen Fang,Yitong Wang,Xiangping Tan
Microbial fuel cell (MFC) exhibits huge potentials in disposing wastewater and extra energy consumption. Exploring useful microorganisms for MFC is the crucial section. Herein, the electrochemical mechanism of extracellular anaerobic respiration in MFC inoculated with gram-positive Rhodococcus pyridinivorans HR-1, was first revealed. The MFC exhibited rapid recovery of currents on anode, and could recover to maximum output within one hour, with redox peaks near −0.38 and −0.18 V through electron transfer between the biofilm and anode. When the biofilm-based pathway was blocked by wrapping the anode with Millipore filter membrane, HR-1 inoculated MFC could still generate electricity within a longer recovery period (∼35 h) during anolyte exchange. This was proposed as a self-secreted electron shuttle pathway for electron transfer in R. pyridinivorans HR-1. Cyclic voltammetry analysis revealed that the biofilm-based and self-secreted electron shuttle-based pathways co-existed in R. pyridinivorans HR-1 inoculated MFC, which could play synergistic roles in electricity generation.
研究领域:
微生物学
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环境科学
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电化学
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DOI
PubMed
高影响因子
Journal of Cleaner Production
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2024
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IF 9.7
Jin-Na Zhang,Xiao-Fan Gong,Guang-guo Ying,An-Guo Wang,Mei-Jun Dong,You-sheng Liu,Tong-Chu Deng,Mei-Ying Xu
In response to the widespread environmental concern of endocrine disruptors, our research investigated the aerobic biodegradation of dexamethasone (DEX), a widely used synthetic glucocorticoid with endocrine-disrupting properties, by strain Rhodococcus sp. D32. This innovative strain showcases remarkable DEX-degrading capabilities, with the half-life for degrading 500 μg/L DEX in MH broth being just 7.56 h. Utilizing high-resolution mass spectrometry, we identified six transformation products (TPs) and revealed a unique steroid nucleus-opening pathway marked by A-ring lactonization and subsequent lactone hydrolysis. This newly discovered pathway deviates from the classical steroid 9,10-seco pathways and previous transformations that preserved the intact steroid nucleus, thus expanding our knowledge of microbial steroid transformations. Additionally, the degradation process progressively converts the parent DEX into less ecotoxic products, significantly reducing the overall ecotoxicity of the system. This reduction remains evident when considering the combined toxicity of DEX and its TPs, indicating a promising approach for lessening environmental harm. Strain D32 also proved effective in various authentic aquatic environments, including fishpond water, urban sewage, river water, and reservoir water, where its introduction markedly expedited the dissipation of DEX. Our findings underscore the potential of strain D32 as a powerful tool for the bioremediation of DEX, presenting an efficient and eco-friendly strategy to alleviate the effects of this endocrine disruptor in aquatic ecosystems.
研究领域:
环境科学
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微生物学
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生物技术
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毒理学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2016
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IF 4.836
Hui Zhang,Mengya Li,Jie Li,Guangli Wang,Feng Li,Dayong Xu,Yuan Liu,Minghua Xiong
A natural consortium, named L1, of Rhodococcus sp. JT-3 and Brevundimonas sp. JT-9 was obtained from quizalofop- p -ethyl (QE) polluted soil. The consortium was able to use QE as a sole carbon source for growth and degraded 100 mg L −1 of QE in 60 h. Strain JT-3 initiated the catabolism of QE to quizalofop acid (QA), which was used by strain JT-9 as carbon source for growth and to simultaneously feed strain JT-3. A novel esterase EstS-JT, which was responsible for the transformation of QE to QA and essential for the mineralization of QE by the consortium, was cloned from strain JT-3. EstS-JT showed low amino acid identity to other reported esterases from esterase family VIII and represents a new member of this family. The deduced amino acid sequence contained the esterase family VIII conserved motifs S-X-X-K, YSV and WAG. The purified recombinant EstS-JT displayed maximal esterase activity at 35 °C and pH 7.5. An inhibitor assay, site-directed mutagenesis and 3D modeling analysis revealed that S 64 , K 67 and Y 175 were essential for catalysis and probably comprised the catalytic center of EstS-JT. Additionally, EstS-JT had broad substrate specificity and was capable of hydrolyzing p -nitrophenyl esters (C 2 -C 8 ) and various AOPP herbicides.
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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产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2023
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IF 9.8
Zhen Rong,Zhi-Hao Ding,Yue-Hong Wu,Xue-Wei Xu
Low-density polyethylene (LDPE), which accounts for 20% of the global plastic production, is discharged in great quantities into the ocean, threatening marine life and ecosystems. Marine microorganisms have previously been reported to degrade LDPE plastics; however, the exploration of strains and enzymes that degrade LDPE is still limited. Here, an LDPE-degrading bacterium was isolated from seawater of the Changjiang Estuary, China and identified as Rhodococcus sp. C-2, the relative abundance of which was dramatically enhanced during PE-degrading microbial enrichment. The strain C-2 exhibited the degradation of LDPE films, leading to their morphological deterioration, reduced hydrophobicity and tensile strength, weight loss, as well as the formation of oxygen-containing functional groups in short-chain products. Sixteen bacterial enzymes potentially involved in LDPE degradation were screened using genomic, transcriptomic, and degradation product analyses. Thereinto, the glutathione peroxidase GPx with exposed active sites catalyzed the LDPE depolymerization with the cooperation of its dissociated superoxide anion radicals. Furthermore, an LDPE degradation model involving multiple enzymes was proposed. The present study identifies a novel PE-degrading enzyme (PEase) for polyethylene bioremediation and promotes the understanding of LDPE degradation.
研究领域:
环境科学
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微生物学
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生物技术
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材料科学
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DOI
PubMed
高影响因子
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2013
·Vol. 97
·期 24
·10329-10337
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IF 3.689
He Yu-Cai,Ma Cui-Luan,Yang Zhen-Xing,Zhou Min,Xing Zhen,Ma Jiang-Tao,Yu Hui-Lei
Enantiopure sulfoxides can be prepared via the asymmetric oxidation of sulfides using sulfide monooxygenases. The n -octane–water biphasic system was chosen for the bio-oxidation of a water-insoluble phenyl methyl sulfide (PMS) by Rhodococcus sp. CCZU10-1. In this n -octane–water system, the optimum reaction conditions were obtained. ( S )-phenyl methyl sulfoxide (( S )-PMSO) with >99.9 % enantiomeric excess formed at 55.3 mM in the n -octane–water biphasic system. Using fed-batch method, a total of 118 mM ( S )-PMSO accumulated in 1-L reaction mixture after the 7th feed, and no ( R )-PMSO and sulfone were detected. Moreover, Rhodococcus sp. CCZU10-1 displayed fairly good activity and enantioselectivity toward other sulfides. In conclusion, Rhodococcus sp. CCZU10-1 is a promising biocatalyst for synthesizing highly optically active sulfoxides.
研究领域:
生物化学
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微生物学
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有机合成
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DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2025
·
IF 11.3
Guoqiang Zhao,Wenjing Chen,Rongrong Zhang,Rui Zhang,Bo Jiang,Ruyan Hou,Xing Huang
Cypermethrin, a common pyrethroid insecticide, raises significant ecological concerns due to its widespread use. In this study, a highly efficient cypermethrin-degrading strain, Rhodococcus sp. H-3, was isolated. The strain was capable of degrading 30 mg/L cypermethrin at the rate of 83.48 % within 7 days and it could hydrolyze cypermethrin into 3-phenoxybenzoic acid (3-PBA) and permethric acid (DCVA). A novel cypermethrin degradation gene, cymE1 , was identified in strain H-3 through genome analysis, and its highest level of amino acid sequence similarity observed was 33.50 % in the Swiss-Prot database. The functional strain, SCK6-E, which could secrete CymE1, was successfully constructed by using double-exchange strategies. Strain SCK6-E could be applied for the removal of cypermethrin residues from tea plant leaves with a removal rate of 57.83 % within 2 h. Furthermore, strain H-3 demonstrated the capability to remediate cypermethrin-contaminated soil, exhibiting a degradation rate of 65.80 % over 10 days. The results of the 16S rRNA high-throughput sequencing indicated that strain H-3 was conducive to the restoration of the diversity and richness of the bacterial community in the soil. This study provides novel strain and gene resources for researching the degradation mechanism of pyrethroids, and offers valuable insights for developing effective pesticide residue remediation strategies.
研究领域:
环境微生物学
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生物修复
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基因组学
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分子生物学
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农业科学
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产品关联
DOI
PubMed
高影响因子
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
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2025
·
IF 3.7
Qian Zhu,Kangning Wei,Kaihua Pan,Gang Hu,Weihao Zhu,Yanni Huang,Changchang Wang,Qian Li,Mingliang Zhang,Jiguo Qiu,Qing Hong
Isoprocarb (IPC), a widely used carbamate insecticide, causes environmental contamination and poses risks to humans and ecosystems. Rhodococcus sp. D-6, capable of utilizing IPC as the sole growth substrate, was isolated by our lab. Strain D-6 initiates IPC degradation through ester bond hydrolysis by the hydrolase IpcH, yielding 2-isopropylphenol (IPP). In this study, the catabolic pathway of IPP in strain D-6 was elucidated, and the ipp gene cluster responsible for its degradation was predicted by transcriptomic analysis. Key genes, including a novel two-component IPP monooxygenase gene ippA1A2 and a 2-isopropylhydroquinone dioxygenase gene ippB, are responsible for the successive conversion of IPP, resulting in the ring cleavage of IPP. IppA1, a group D flavin-dependent monooxygenase, along with its reductase component IppA2, hydroxylates IPP to 2-isopropylhydroquinone using reduced nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) as cofactors. The optimal molar ratio of IppA1 to IppA2 was 3:1. The apparent Km and kcat values of IppA1 for IPP were 60.52 ± 1.27 µM and 70.07 ± 0.85 s−1, respectively. IppB, an extradiol dioxygenase, catalyzes 2-isopropylhydroquinone ring cleavage to generate 2-isopropyl-4-hydroxymuconic semialdehyde. The apparent Km and kcat values of IppB for 2-isopropylhydroquinone were 29.07 ± 1.54 μM and 147.65 ± 1.92 s−1, respectively. This study provides critical insights into the molecular mechanisms of IPP degradation, contributing to a comprehensive understanding of IPC degradation.
研究领域:
环境微生物学
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生物降解
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分子生物学
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生物化学
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基因组学
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农药代谢
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2023
·
IF 13.6
Yongrui Pi,Wenpeng Jia,Shengkai Chi,Hongke Meng,Yongzheng Tang
The Chlorella vulgaris - Rhodococcus erythropolis consortia was constructed for the biodegradation of waste motor oil (WMO), combined with thermodynamic calculations and stoichiometric analyses. The microalgae-bacteria consortium was constructed as C. vulgaris : R. erythropolis = 1:1 (biomass, cell/mL), pH = 7, 3 g/L WMO. Under the same condition, the terminal electron acceptors (TEAs) play a crucial role in the WMO biodegradation, which follows Fe 3+ >SO 4 2- > none. The biodegradation of WMO fitted well with the first-order kinetic model under experimental temperatures with different TEAs ( R 2 >0.98). The WMO biodegradation efficiency reached 99.2 % and 97.1 % with Fe 3+ and SO 4 2− as TEAs at 37 °C, respectively. Thermodynamic methanogenesis opportunity windows with Fe 3+ as TEA are 2.72 times fold as large as those with SO 4 2- . Microorganism metabolism equations demonstrated the viability of anabolism and catabolism on WMO. This work lays the groundwork for the implementation of WMO wastewater bioremediation and supports research into the biochemical process of WMO biotransformation .
研究领域:
环境科学
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微生物学
✓ 已验证
DOI
PubMed
高影响因子
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