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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DOI
PubMed
高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
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2021
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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
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CHEMOSPHERE
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2022
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IF 8.943
Bohan Yuan,Jiachao Yao,Zeyu Wang,Luyao Dai,Min Zhao,Dzmitry Hrynsphan,Savitskaya Tatsiana,Jun Chen
In this work, Rhodococcus ruber HJM-8 and Paracoccus communis YBH-X were isolated and used to enhance N , N -dimethylacetamide (DMAC) degradation and mineralization efficiencies. The monoculture and co-culture of the two strains for DMAC degradation were compared; results indicated that, a degradation efficiency of 97.62% was obtained in co-culture, which was much higher than that of monocultures of HJM-8 (57.34%) and YBH-X (34.02%). The degradation mechanism showed that co-culture could efficiently improve extracellular polymeric substances production, electron transfer , and microbial activity . Meanwhile, the mineralization mechanism suggested that acetate was the dominant intermediate which had an inhibitory effect on HJM-8, and co-culture was conducive to mineralization due to the high performance of acetate conversion and Na + K + -ATPase vitality. Besides, a pathway of DMAC biodegradation was proposed for co-culture: DMAC was degraded into acetate by HJM-8, then the accumulated acetate was mineralized by YBH-X. Additionally, the co-culture system was further optimized by Box-Behnken design.
研究领域:
环境微生物学
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生物修复
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化学工程
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DOI
PubMed
高影响因子
MARINE POLLUTION BULLETIN
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2025
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IF 4.9
Jia Shi,Dan Xu,Qiao Ma
p -Chloro- m -xylenol (PCMX), a widely used antimicrobial agent, poses potential ecological risks due to its ubiquitous distribution and documented toxicity to aquatic vertebrates. Although microbial degradation represents a key natural attenuation pathway, the molecular mechanisms governing PCMX biodegradation remain elusive. Here, we report the isolation of three novel Rhodococcus strains from marine sediments capable of mineralizing PCMX. Among these, strain R. ruber SJ-1 completely metabolized 30 mg/L PCMX within 72 h and maintained significant degradation capacity under high-salinity stress. Integrated genomic and transcriptomic analyses revealed that PCMX exposure triggered extensive transcriptional reprogramming in strain SJ-1, with 1063 genes upregulated and 533 downregulated. PCMX inhibited core cellular functions, including key genes related to cell stress resistance, energy production, central carbon metabolism, fatty acid metabolism, and protein biosynthesis. Concurrently, aromatic catabolism pathways were markedly induced. A highly upregulated gene cluster ( sj4821 - sj4838 ) was identified as pivotal for PCMX metabolism, encompassing a flavin-dependent monooxygenase (NphA1-sj, sj4831 ; 2145.26-fold) and catechol 2,3-dioxygenase (C23O, sj4838 , 2052.43-fold) genes. Quantitative PCR assays further validated the upregulation patterns. Based on bioinformatics and high-resolution mass spectrometry analyses, we proposed that strain SJ-1 converted PCMX to 4-chloro-3,5-dimethylcatechol via ortho -hydroxylation, followed by meta -cleavage of the aromatic ring. This study presents the first documented evidence of PCMX degradation by a marine Rhodococcus isolate. Our findings reveal the molecular mechanisms driving PCMX detoxification and cellular adaptation, establishing a foundation for bioremediation in saline ecosystems.
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高影响因子
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