CHEMOSPHERE
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2015
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IF 3.34
Jing-Nan Jin,Jun Yao,Qing-Ye Zhang,Chan Yu,Peng Chen,Wen-Juan Liu,Dan-Ning Peng,Martin M.F. Choi
Naphthalene dioxygenase (NDO) is the initial enzyme catalyzing the biodegradation of aromatic compounds, and it plays a key role in microbial remediation of polluting sites. In this study, Rhodococcus sp. ustb-1 derived from crude oil was selected to investigate the biodegradation characters and dihydroxylation mechanism of pyrene by an integrated approach of bioassay and molecular docking. The biodegradation experiment proved that the strain ustb-1 shows high effective biodegradability to pyrene with a 70.8% degradation on the 28th day and the metabolite pyrene cis-4,5-dihydrodiol was found. The results of molecular docking indicated that the regions surrounding pyrene are defined by hydrophobic amino acids which are favorable for the binding of dioxygen molecule at C4 and C5 positions of pyrene in a side-on mode. The binding positions of dioxygen are in agreement with the mass spectral analysis of the metabolite pyrene cis-4,5-dihydrodiol. In summary, this study provides a promising explanation for the possible binding behavior between pyrene and active site of NDO.
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Biomolecules
·
2019
·Vol. 9
·期 11
·695
·
IF 4.694
Dong-Sheng Wang,Xin-Jun Yu,Xiao-Yu Zhu,Zhao Wang,Hui-Juan Li,Zhi-Peng Wang
In the current study, corn steep liquor (CSL) is evaluated as an ideal raw agro-material for efficient lipid and docosahexaenoic acid DHA production byAurantiochytriumsp. Low CSL level in medium (nitrogen deficiency) stimulated the biosynthesis of lipids and DHA while inhibiting cellular growth. The transcriptomic profiles of theAurantiochytriumsp. cells are analyzed and compared when cultured under high (H group), normal (N group), and low (L group) levels of CSL in the medium. The discriminated transcriptomic profiles from the three groups indicates that changes in CSL level in medium result in a global change in transcriptome ofAurantiochytriumsp. The overall de novo assembly of cDNA sequence data generated 61,163 unigenes, and 18,129 of them were annotated in at least one database. A total of 5105 differently expressed (DE) genes were found in the N group versus the H group, with 2218 downregulated and 2887 upregulated. A total of 3625 DE genes were found in the N group versus the L group, with 1904 downregulated and 1721 upregulated. The analysis and categorization of the DE genes indicates that the regulation mechanism of CSL involved in the perception and transduction of the limited nitrogen signal, the interactions between the transcription factors (TFs) and multiple downstream genes, and the variations in downstream genes and metabolites, in sequence, are illuminated for the first time in the current study.Keywords:Aurantiochytriumsp.;nitrogen-deficiency;RNA-seq;corn steep liquor (CSL);signal transduction;DHA
研究领域:
生物技术
·
分子生物学
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Meng Shi,Demin Kong,Hui Zhang,Deming Rao,Tianlong Zhao,Jing Yang,Zhanzhi Liu,Sheng Chen,Fengshan Zhang,Jing Wu,Lei Wang
Latex clearing protein from Streptomyces sp. strain K30 (Lcp K30 ) is a natural oxidoreductase that can catalyse the cleavage of rubber through dioxygenation. It has significant potential applications in polymer degradation. However, its limited expression in engineered strains restricts its utility. This study aimed to enhance the soluble expression and enzyme activity of Lcp K30 in E. coli BL21 (DE3) by optimizing fermentation conditions and making molecular modifications. The enzyme activity reached 5.05 U·mL −1 by optimizing the induction conditions, adding cofactors, and using chemical chaperones , which was 237.1 % of the initial case. Further enhancements in soluble expression were achieved through site mutations guided by the PROSS server, resulting in 8 out of 13 mutants with increased protein expression , a high positive mutation rate of 61.5 %. Subsequently, combined mutants were created by merging single mutants with enhanced protein expression and enzyme activity. The top three double mutants, G91D/S149A, G91D/A210H, and G91D/H296P, displayed expression levels at 173.3 %, 173.3 %, and 153.3 % of the wild-type Lcp K30 , respectively. These mutants also exhibited enhanced fermentation enzyme activity, reaching 149.5 %, 250.0 %, and 420.2 % compared to the wild-type, along with improved specific activities. This study provides insights for the efficient production of Lcp K30 and a practical foundation for its application.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Qian Li,Jiahui Zhang,Jiayu Zhou,Wang Xu,Zhuowei Cheng,Piet N.L. Lens,Jianmeng Chen,Dongzhi Chen
The effective and economic treatment of chlorobenzenes has become one of the most intractable issues in the field of air pollution control. Herein, a visible-light photocatalysis coupled with biodegradation (VPCB) system was developed by integrating an innovative visible-light responsive TiO 2 /oxygenous groups decorated g-C 3 N 4 (TiO 2 /OCN) with polyurethane carriers immobilized with Ralstonia sp. XZW-1 for chlorobenzene removal. Performance tests showed that light intensity, preparation of the MICs, catalyst dosage and composition of the TiO 2 /OCN cast significant influence on chlorobenzene removal efficiency, with the degradation efficiency, mineralization and dechlorination ratios of VPCB achieving 100%, 35.5%, and 99.4% under the optimal conditions, respectively, outcompeting the sum of visible-light photocatalytic system and biodegradation protocols. Cycling tests further demonstrated the excellent stability of VPCB. Mechanism analysis found that increased reactive sites, improved visible-light harvesting, accelerated charge transfer and separation, and the resulting abundant active species jointly contributed to the enhanced photocatalytic activity of TiO 2 /OCN. Photogenerated holes were most significant active species for chlorobenzene removal, followed by OH and O 2 − radicals. The carriers could effectively protect microorganisms from light illumination and strong oxidizing species, allowing the further microbial metabolism of chlorobenzene photocatalytic oxidation intermediates with good biodegradability, not only greatly promoting the microbial growth and activity, but further enhancing chlorobenzene photocatalytic degradation. Plausible synergistic mechanism for chlorobenzene degradation between photocatalysis and biodegradation was also revealed. Furthermore, the VPCB system constructed presented wide applicability towards various pollutants, and its performance was found closely related with the hydrophobicity of pollutants. This work provided insight into the design and application of the VPCB system for the efficient and economic treatment of refractory pollutants.
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Journal of Water Process Engineering
·
2023
·
IF 7
Yimin Xie,Naiwen Chen,Zhiwei Liang,Yihuai Huang,Hojae Shim
An indigenous bacterial strain, Bacillus sp. MY156, was isolated from a local wastewater treatment plant and utilized for degradation of dibutyl phthalate (DBP) and diethyl phthalate (DEP). The isolate showed a substrate preference of DBP to DEP. The optimal biodegradation conditions were pH 7, 30 °C, 0.2 (in terms of OD 600 ) inoculum size, and 2 % (v v −1 ) bacterial load. The biodegradation of DBP and DEP as sole carbon source was comprehensively investigated via degradation kinetics and mass balance analysis. The isolate achieved complete degradation and over 80 % removal of 300 mg L −1 DBP within 60 h and 200 mg L −1 DEP in 5 days. The biodegradation of DBP and DEP fitted the inhibitory kinetic model, and the maximum degradation rates for DBP and DEP were 183.34 and 66.90 mg L −1 day −1 , respectively. The cell surface responses to biodegradation were investigated by analyses of morphology, Fourier transform-infrared, and extracellular polymeric substance. The potential intermediates were mono-n-butyl phthalate, mono-ethyl phthalate, phthalic acid, and protocatechuic acid by β-oxidation, hydrolysis, and decarboxylation . The esterase and dehydrogenase activities reached the highest at the initial and middle phases during biodegradation. The docking studies also elucidated the relevant enzyme preferred DBP to DEP via binding energy and bond distance.
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AMB Express
·
2018
·Vol. 8
·期 1
·1-12
·
IF 1.719
Hu Xingcui,Cheng Tao,Liu Jianhua
Biosurfactants emulsify lipids, facilitating their exposure to microorganisms in water. Secretion of biosurfactant together with lipase can enhance oil assimilation by microorganisms. In this study, we show the analysis of the biosurfactant and lipase producing microbe originating from oil-sludge. The enrichment of the biosurfactant-producing ZS6 strain from the mixed culture of sludge-derived microbes in medium with olive oil as sole carbon source was monitored using the modified T-RFLP (or mT-RFLP) methodology. Phylogenetic tree analysis based on 16S rDNA sequences suggested that ZS6 belonged to a member of Serratia sp. Serratia sp. ZS6 secreted both a serrawettin-type biosurfactant and lipase in medium with olive oil as sole carbon source. By using an in-gel lipase assay followed by LC–MS/MS analysis, we identified the amino acid sequences of the ZS6 lipase, which belonged to the lipase subfamily III of the family I. Its lipolytic activity was found to be enhanced by salinity, calcium, and methanol. Together, we show that the novel isolate Serratia sp. ZS6 secretes both biosurfactant and lipase which makes it useful for applications such as in food industry wastewater treatment and biodiesel production.
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EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2022
·Vol. 249
·期 3
·685-697
·
IF 3.498
Huang Yicheng,Zhong Meiqiao,Mu Siyu,Han Yan,Shi Yu,Li Xiaolei,Li Dan
Abstract The production of waxy rice wine (WRW) usually requires multiple strains for fermentation. However, information about the contributions of individual strains to the quality of WRW remains limited. In this study, WRWs were produced through fermentation with three strains ( Saccharomyces cerevisiae H1 [Sc], Hansenula sp. H3 [Hs] and Pichia kudriavzevii H6 [Pk]), and the quality of the WRWs was evaluated. The results indicated that Sc wine produced high levels of phenylethyl alcohol and 3-methyl-1-butyl acetate, reaching 31,622.78 μg/L and 351.67 μg/L, respectively; Hs wine produced the highest contents of ethyl acetate and lactic acid, reaching 69,535.58 μg/L and 17.46 g/L, respectively, and had the highest score for “acidic”; Pk wine produced high contents of 2-methyl-1-propanol, 3-methyl-1-butanol and 2-methyl-1-butanol, reaching 46,951.56 μg/L, 163,674.83 μg/L and 52,238.51 μg/L, respectively. The average concentrations of ethyl acetate, 2-methyl-1-propanol, and 3-methyl-1-butanol in mixed fermentation products increased by 126.80%, 25.82% and 17.02% compared to Sc wine, respectively, thus increasing the sensory scores for “malty” and “acidic”. In addition, high ethanol content resulted in higher scores for “winey” in WRWs. These results reveal the potential of S. cerevisiae H1 to produce ethanol, Hansenula sp. H3 to produce esters and P. kudriavzevii H6 to produce alcohols in WRW. Simultaneously, advantages of mixed fermentation for integrating the characteristics of various pure cultures were observed, namely increasing the number of volatile organic compounds (VOCs) and appropriately extending the fermentation time. The application of mixed fermentation has the potential to enrich the flavour and improve the quality of WRWs. Graphical abstract
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Frontiers in Microbiology
·
2022
·
IF 6.064
Chen Yan,Zhou Ning,Chen Xueman,Wei Guoguang,Zhang Alei,Chen Kequan,Ouyang Pingkai
In this study, a gene encoding β-N-acetylglucosaminidase, designated NAGaseA, was cloned from Chitinibacter sp. GC72 and subsequently functional expressed in Escherichia coli BL21 (DE3). NAGaseA contains a glycoside hydrolase family 20 catalytic domain that shows low identity with the corresponding domain of the well-characterized NAGases. The recombinant NAGaseA had a molecular mass of 92 kDa. Biochemical characterization of the purified NAGaseA revealed that the optimal reaction condition was at 40°C and pH 6.5, and exhibited great pH stability in the range of pH 6.5–9.5. The Vmax, Km, kcat, and kcat/Km of NAGaseA toward p-nitrophenyl-N-acetyl glucosaminide (pNP-GlcNAc) were 3333.33 μmol min–1 l–1, 39.99 μmol l–1, 4667.07 s–1, and 116.71 ml μmol–1 s–1, respectively. Analysis of the hydrolysis products of N-acetyl chitin oligosaccharides (N-Acetyl COSs) indicated that NAGaseA was capable of converting N-acetyl COSs ((GlcNAc)2–(GlcNAc)6) into GlcNAc with hydrolysis ability order: (GlcNAc)2 > (GlcNAc)3 > (GlcNAc)4 > (GlcNAc)5 > (GlcNAc)6. Moreover, NAGaseA could generate (GlcNAc)3–(GlcNAc)6 from (GlcNAc)2–(GlcNAc)5, respectively. These results showed that NAGaseA is a multifunctional NAGase with transglycosylation activity. In addition, significantly synergistic action was observed between NAGaseA and other sources of chitinases during hydrolysis of colloid chitin. Finally, 0.759, 0.481, and 0.986 g/l of GlcNAc with a purity of 96% were obtained using three different chitinase combinations, which were 1.61-, 2.36-, and 2.69-fold that of the GlcNAc production using the single chitinase. This observation indicated that NAGaseA could be a potential candidate enzyme in commercial GlcNAc production.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 32
·48638-48647
·
IF 5.19
Li Qian,Tang Zeqin,Zhang Jiahui,Hu Jingtao,Chen Jianmeng,Chen Dongzhi
Simultaneous biodegradation of malodorous 1-propanethiol (PT) and dimethyl sulfide (DMS) by Pseudomonas putida S-1 and Alcaligenes sp. SY1 was investigated and the interactions implicated were explored. Results showed that PT was completely degraded in 33 h, while a lag of 10 h was observed for DMS degradation alone, and the lag was even extended to 81 h in the binary mixture. Mechanism analysis found that the lag was mainly attributed to the exposure of DMS degrader ( Alcaligenes sp. SY1), rather than PT metabolites and PT degrader. The exposure time and PT concentration also influenced the lag duration much. Citric acid could effectively reduce the lag. Pseudo-first-order model was proved suitable for the description of PT degradation, revealing that PT degradation could be enhanced in presence of DMS with a concentration of < 50 mg L −1 . A modified Gompertz model, incorporated the lag phase, was developed for the description of DMS degradation in the mixture, revealing that DMS degradation depended on the initial PT concentration, and when the lag was not considered, PT with low-concentration could promote DMS biodegradation, while a higher concentration (> 20 mg L −1 ) cast negative effect.
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JOURNAL OF MEMBRANE SCIENCE
·
2022
·
IF 10.53
Hongli Xie,Liguo Shen,Yanchao Xu,Huachang Hong,Lining Yang,Renjie Li,Hongjun Lin
Wettability of membrane is of vital importance for treatment of oily wastewater. In recent years, hydrophilic modifications based on plant polyphenol have been widely investigated to enhance the anti-fouling property of membranes due to their mild conditions, versatility and low cost. However, there are still some problems in improving raw material utilization and hydrophilicity. Herein, a facile method was proposed to optimize tannic acid (TA)-based membrane modification process by synergistically inducing TA deposition by Fe 3+ and SP with the assistance of inkjet printing. The hydrophobicity of polyvinylidene fluoride (PVDF) membrane was converted to hydrophilicity (WCA = 34.6°) and underwater oleophobicity (UOCA = 144.4°) in very short time (10 min). The optimum PVDF/Fe-TA-SP 422 membrane possessed high flux (4968.4–7340.4 L m −2 h −1 ·bar −1 ) for a number of oil/water emulsions with high separation efficiency (>98%), outperforming most state-of-the-art membranes for oil-water separation. Furthermore, the optimized membrane displayed not only high antifouling property and reusability with flux recovery ratio of 89.1%–98.0% after eight-cycle filtration, but also desired stability under near neutral pH conditions during long-term running. The combination of inkjet printing method with these materials proposed in this study is convenient, efficient and low cost, and the prepared membranes are versatility, providing novel insights into preparation of high efficiency membranes for oily wastewater treatment .
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FOOD CHEMISTRY
·
2021
·
IF 7.514
Ruiguo Cui,Long Xu,Dongming Lan,Bo Yang,Yonghua Wang
Our study offers a novel sn -1,3 specific lipase MAJ1 from marine member Janibacter sp. strain HTCC2649 for preparing long-medium-long (LML) type structured triacylglycerols (TAGs). Firstly, the resin ECR1030 was selected as a suitable support for the immobilization of lipase MAJ1. An efficient synthesis of LML-type structured TAGs by the immobilized lipase MAJ1-catalyzed interesterification of methyl palmitate and tricaprylin was studied in a solvent-free system. The reaction conditions, including substrate molar ratio, temperature and enzyme loading, were optimized. Under the optimum conditions (immobilized lipase MAJ1 of 45 U/g, substrate molar ratio of 4:1, temperature of 35 °C, reaction time of 24 h), the structured TAGs with double long chains (DLCST) were obtained in a yield of 44.3 mol%. Secondly, multi-dimensional mass spectrometry-based shotgun lipidomics (MDMS-SL) was employed to quantify each TAG positional isomer in DLCST. The content of 1,3-dipalmitoyl-2-capryloyl- sn -glycerol in DLCST was 97.6% determined by the MDMS-SL technology.
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JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Kaili Xu,Yimeng Li,Qian Li,Guorong Yi,Runyu Gao,Kuok Ho Daniel Tang,Esmat F. Ali,Peter.S. Hooda,Sabry M. Shaheen,Ronghua Li
Bisphenol-A (BPA) is an emerging hazardous contaminant, which is ubiquitous in the environment and can cause endocrine disruptor and cancer risks. Therefore, biodegradation of BPA is an essential issue to mitigate the associated human health. In this work, a bacterial strain enables of degrading BPA, named BPA-LRH8 (identified as Xenophilus sp.), was newly isolated from activated sludge and embedded onto walnut shell biochar (WSBC) to form a bio-composite (BCM) for biodegradation of BPA in water. The Langmuir maximum adsorption capacity of BPA by WSBC was 21.7 mg g −1 . The free bacteria of BPA-LRH8 showed high BPA degradation rate (∼100 %) at pH 5–11, while it was lower (＜20 %) at pH 3. The BCM eliminated all BPA (∼100 %) at pH 3–11 and 25–45 °C when the BPA level was ≤ 25 mg L −1 . The spectrometry investigations suggested two possible degradation routes of BPA by Xenophilus sp. In one route, BPA (C 15 H 16 O 3 ) was oxidized to C 15 H 16 O 3 , and then broken into C 9 H 12 O 3 through chain scission. In another route, BPA was likely hydroxylated, oxidized, and cleaved into C 9 H 10 O 4 P 4 , which was further metabolized into CO 2 and H 2 O in the TCA cycle. This study concluded that the novel isolated bacteria (BPA-LRH8) embedded onto WSBC is a promising and new method for the effective removal of BPA and similar hazardous substances from contaminated water under high concentrations and wide range of pH and temperature.
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