3 Biotech
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2023
·Vol. 13
·期 10
·1-11
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IF 2.8
Zhao Zhenzhen,Liu Yanfeng,Liu Chao,Xu Qianqian,Song Meijie,Yan Hai
Extensive use of phthalic acid esters (PAEs) as plasticizer causes diffusion into the environment, which posed a great threat to mankind. It was reported that Comamonas sp. was a potentially robust aromatic biodegrader. Although the biodegradation of several PAEs by Comamonas sp. was studies, the comprehensive genomic analysis of Comamonas sp. was few reported. In the present study, one promising bacterial strain for biodegrading diethyl phthalate (DEP) was successfully isolated from activated sludge and characterized as Comamonas sp. USTBZA1 based on the 16S rRNA sequence analysis. The results showed that pH 7.5, 30 °C and inoculum volume ratio of 6% were optimal for biodegradation. Initial DEP of 50 mg/L could be completely biodegrade by strain USTBZA1 within 24 h which conformed to the Gompertz model. Based on the Q-TOF LC/MS analysis, monoethyl phthalate (MEP) and phthalic acid (PA) were identified as the metabolic products of DEP biodegradation by USTBZA1. Furthermore, the whole genome of Comamonas sp. USTBZA1 was analyzed to clarify the molecular mechanism for PAEs biodegradation by USTBZA1. There were 3 and 41 genes encoding esterase/arylesterase and hydrolase, respectively, and two genes regions ( pht 34512 and pht 4253) were responsible for the conversion of PA to protocatechuate (PCA), and two genes regions ( lig CBAIKJ) were involved in PCA metabolism in USTBZA1. These results substantiated that Comamonas sp. USTBZA1 has potential application in the DEP bioremediation.
研究领域:
环境生物学
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微生物学
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DOI
PubMed
高影响因子
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
·
2021
·Vol. 87
·期 8
·
IF 4.792
Chao-Fan Yin,Ying Xu,Shi-Kai Deng,Wen-Long Yue,Ning-Yi Zhou
As a water-soluble polymer, the widely used polyvinyl alcohol (PVA) is produced from hydrolysis of polyvinyl acetate. Microbial PVA carbon backbone cleavage via a two-step reaction of dehydrogenation and hydrolysis has been well studied. The content of the acetyl group is a pivotal factor affecting performance of PVA derivatives in industrial applications, and deacetylation is a nonnegligible part of PVA degradation. However, the genetics and biochemistry of its deacetylation remain largely elusive. Here, Comamonas sp. strain NyZ500 was isolated for its capability of growing on acetylated PVA from activated sludge. The spontaneous PVA utilization-deficient mutant strain NyZ501 was obtained when strain NyZ500 was cultured in rich media. Comparative analysis between the genomes of these two strains revealed a fragment (containing a putative hydrolase gene, dacApva) deletion in strain NyZ501, and in the dacApva-complemented strain NyZ501 the ability to grow on PVA was restored. DacApva, which shares 21% identity with xylan esterase AxeA1 from Prevotella ruminicola 23, is a unique deacetylase catalyzing the conversion of acetylated PVA and its derivatives to deacetylated counterparts. This indicates that strain NyZ500 utilizes acetylated PVA via acetate as a carbon source to grow. DacApva also possesses the ability to deacetylate acetylated xylan and the antibiotic intermediate 7-aminocephalosporanic acid (7ACA), but the enzymes responsible for the conversion of those two compounds have no activity against PVA derivatives. This study enhanced our understanding of the diversity of microbial degradation of PVA, and DacApva characterized here is also a potential biocatalyst for the eco-friendly biotransformation of PVA derivatives and other acetylated compounds.IMPORTANCE Water-soluble PVA, which possesses a very robust ability to accumulate in the environment, has a very grave environmental impact due to its widespread use in industrial and household applications. On the other hand, chemical transformation of PVA derivatives is currently being carried out under high-energy-consumption and high-pollution conditions using hazardous chemicals (such as NaOH and methanol) under high temperatures. The DacApva reported here performs PVA deacetylation under mild conditions, so it has great potential to be developed into an eco-friendly biocatalyst for biotransformation of PVA derivatives. DacApva also has deacetylation activity for compounds other than PVA derivatives, which facilitates its development into a broad-spectrum deacetylation biocatalyst for production of certain desired compounds.
研究领域:
环境科学
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生物化学
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微生物学
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PubMed
高影响因子
ENVIRONMENTAL RESEARCH
·
2023
·
IF 8.3
Shuai Zhang,Junfeng Su,Shuyu Liu,Yi Ren,Shumiao Cao
There is an urgent demand to investigate mechanisms for the improvement of denitrification in carbon-deficient environment, which will effectively reduce the eutrophication in water bodies polluted by nitrate. In this study, denitrifying bacterium Comamonas sp. YSF15 was used to explore the differences in different carbon source concentrations, with the complete genome, metabolomics, and other detecting methods. Results showed that strain YSF15 was able to achieve efficient denitrification, with complete pathways for denitrification and central carbon metabolism. The carbon deficiency prompted the bacteria to use extracellular amino acid-like metabolites initially, to alleviate inhibition and maintain bioactivity , which also facilitated glycogen storage. The biogenic inhibitors (tautomycin, navitoclax, and glufosinate) at extremely low level potentially favored the competitiveness and intraspecific utilization of extracellular polysaccharides (PS). Optimal solutions for bioaggregation in carbon-deficient condition are achieved by regulating the hydrophobicity , and hydrogen bond in extracellular metabolites. The strategy contributes to the maintenance of bioactivity and adaptation to carbon deficiency. Overall, this study provides a new perspective on understanding the denitrification strategies in carbon-deficient environment, and helps to improve the nitrate removal in low-carbon wastewater treatment .
研究领域:
环境微生物学
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废水处理
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代谢组学
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基因组学
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高影响因子
APPLIED GEOCHEMISTRY
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2026
·
IF 3.5
Rong Peng,Rui Yang,Yuhang Liang,Haichuan Sun,Hui Liu
In anaerobic underground environments, the iron redox cycle is fundamentally driven by microbial activities, wherein the metabolic capacity of individual strains plays a pivotal role. This study investigated the regulatory mechanisms of three carbon sources — acetate, glucose, and lactate — on the iron redox cycle mediated by Comamonas sp. HJ-2 under neutral pH anaerobic conditions in Fe(III)–Fe(II) coexisting and Fe(III)-free systems. The results demonstrated that glucose enhanced Fe(II) bio-oxidation and Fe(III) bio-reduction by promoting energy metabolism. Glucose promoted sustained FMN accumulation, which is consistent with a potential contribution of the glycolysis-pentose phosphate pathway-riboflavin synthesis axis, which accumulated to a final concentration of approximately 0.40 μM. The accumulated FMN may function as an electron shuttle and thereby contribute to Fe(III) reduction. Mineralogical analyses further showed system-dependent effects of glucose. In ferrihydrite-containing systems, glucose inhibited the transformation of ferrihydrite toward more crystalline iron phases, whereas in ferrihydrite-free systems it shifted the product distribution toward a higher proportion of ferrihydrite and a lower proportion of lepidocrocite. Glucose also increased the content of surface-bound Fe(II) on minerals. In conclusion, glucose emerged as the most effective carbon source for optimizing the HJ-2-driven iron redox coupling process, likely due to its association with enhanced energy metabolism, FMN accumulation, and altered mineral phase transformation. This study elucidates the carbon source-dependent mechanisms governing microbial iron cycling in anaerobic environments and highlights the critical role of carbon source selection in enhancing iron biotransformation efficiency.
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高影响因子
Food Bioscience
·
2026
·
IF 6.2
Yan Zheng,Heng Hu,Mengying Jiang,Yingying Zhu,Wanmeng Mu
Indigo, one of the oldest dyes still widely used in textiles, food, and pharmaceuticals, requires sustainable microbial production due to the high environmental burden and energy intensity of its chemical synthesis. In this study, indigo biosynthesis was enabled in E. coli MG1655 through heterologous expression and optimization of tryptophanases (TnaAs) and naphthalene dioxygenases (NDOs). To improve strain robustness for production, genes involved in the oxidative stress response were integrated into the chromosome, and gldA was overexpressed to ensure cofactor NADH availability. Furthermore, co-expression of molecular chaperone genes was employed to enhance the soluble expression of NDO. Following these multi-step optimizations, the final engineered strain achieved an indigo titer of 2.38 g/L in shake-flask fermentation. Finally, we demonstrated that fed-batch cultivation in a 5 L bioreactor yielded 6.90 g/L of indigo.
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高影响因子
JOURNAL OF BACTERIOLOGY
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2017
·Vol. 200
·期 1
·
IF 3.143
Hao Yu,Shuxue Zhao,Lizhong Guo
The 1,125-bp mabB gene encoding 5-aminosalicylate (5ASA) 1,2-dioxygenase, a nonheme iron dioxygenase in the bicupin family that catalyzes the cleavage of the 5ASA aromatic ring to form cis-4-amino-6-carboxy-2-oxohexa-3,5-dienoate in the biodegradation of 3-aminobenzoate, was cloned from Comamonas sp. strain QT12 and characterized. The deduced amino acid sequence of the enzyme has low sequence identity with that of other reported ring-cleaving dioxygenases. MabB was heterologously expressed in Escherichia coli cells and purified as a His-tagged enzyme. The optimum pH and temperature for MabB are 8.0 and 10°C, respectively. FeII is required for the catalytic activity of the purified enzyme. The apparent Km and Vmax values of MabB for 5ASA are 52.0 ± 5.6 μM and 850 ± 33.2 U/mg, respectively. The two oxygen atoms incorporated into the product of the MabB-catalyzed reaction are both from the dioxygen molecule. Both 5ASA and gentisate could be converted by MabB; however, the catalytic efficiency of MabB for 5ASA was much higher (∼70-fold) than that for gentisate. The mabB-disrupted mutant lost the ability to grow on 3-aminobenzoate, and mabB expression was higher when strain QT12 was cultivated in the presence of 3-aminobenzoate. Thus, 5ASA is the physiological substrate of MabB.IMPORTANCE For several decades, 5-aminosalicylate (5ASA) has been advocated as the drug mesalazine to treat human inflammatory bowel disease and considered the key intermediate in the xenobiotic degradation of many aromatic organic pollutants. 5ASA biotransformation research will help us elucidate the microbial degradation of these pollutants. Most studies have reported that gentisate 1,2-dioxygenases (GDOs) can convert 5ASA with significantly high activity; however, the catalytic efficiency of these enzymes for gentisate is much higher than that for 5ASA. This study showed that MabB can convert 5ASA to cis-4-amino-6-carboxy-2-oxohexa-3,5-dienoate, incorporating two oxygen atoms from the dioxygen molecule into the product. Unlike GDOs, MabB uses 5ASA instead of gentisate as the primary substrate. mabB is the first reported 5-aminosalicylate 1,2-dioxygenase gene.
研究领域:
微生物学
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环境科学
·
分子生物学
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高影响因子
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