PROCESS BIOCHEMISTRY
·
2018
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IF 2.616
Yufen Wang,Guohua Hou,Jinglei Li,Maheen Mahwish Surhio,Ming Ye
An exopolysaccharide (LEP) was isolated from the fermented broth of Lachnum YM240. The structure of LEP was analyzed by fourier transform infrared spectrometry (FT-IR), high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC MS), and 1D and 2D-nuclear magnetic resonance spectroscopy (NMR). The carboxymethylated and sulfated derivatives of LEP was difined as CLEP and SLEP which with molecular weight ( Mw ) of 3.64 × 10 4 and 2.17 × 10 4 g/mol respectively. The yield of CLEP and SLEP were 60.27 ± 3.04% and 42.88 ± 2.16%, with degree of substitution ( DS ) values of 0.36 and 0.14 respectively. The result of antioxidant activity and hypoglycemic activity showed that CLEP with higher ( DS ) and ( Mw ) exhibited stronger antioxidant abilities on scavenging DPPH radical and hydroxyl radical compared with SLEP and LEP, with EC 50 value of 1.05 and 0.80 mg/mL respectively. The reducing power of CLEP (0.533) and SLEP (0.428) was greater than LEP (0.353). In addition, CLEP and SLEP showed higher alpha-glucosidase inhibitory and alpha-amylase inhibition activities and exhibited significant inhibitory effects against the diffusion of glucose compared to LEP. Furthermore, CLEP and SLEP showed more significant effects than LEP at the same dosage, indicating that carboxymethylation and sulfation modifications were effective ways to enhance antioxidant and hypoglycemic activities of the polysaccharide .
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Biomass Conversion and Biorefinery
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2022
·Vol. 13
·期 18
·16807-16818
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IF 4.05
Wang Qing,Jin Wenbiao,Han Wei,Song Kang,Chen Yidi,Chen Chuan,Jiang Guangming,Zhou Xu
In order to achieve strain improvement and reduction of fermentation medium cost, atmospheric and room temperature plasma (ARTP) mutagenesis and microbial microdroplet culture (MMC) high-throughput screening were used to obtain high-yield Aurantiochytrium sp. strain. Meanwhile, low-cost food waste liquid was added into culture medium to reduce cost. The results showed that the optimal treatment time of ARTP mutagenesis for Aurantiochytrium sp. was 25 s, and 20 mutant strains were screened out by MMC to investigate their performance. The most significant increase in DHA yield was mutant Aurantiochytrium sp. MA20, whose biomass, lipid, and DHA yield were 29.0 ± 0.24, 15.8 ± 0.11, and 9.22 ± 0.37 g/L and 5.77, 16.9, and 83.2% higher than those of original strain, respectively. Compared with the original strain, the DHA proportion in total fatty acids of Aurantiochytrium sp. MA20 increased from 37.2 to 58.3%, while the DHA proportion in biomass increased from 18.4 to 31.7%. The genetic stability for Aurantiochytrium sp. MA20 showed that the yield of biomass, lipid, and DHA of the 50th generation were 29.1 ± 0.13, 16.2 ± 0.31, and 9.47 ± 0.26 g/L, respectively, which was no significant difference between original strain, indicating that the mutant MA20 could be inherited stably. Using food waste liquid to replace 100% yeast extract and 50% sea water of the fermentation medium, the DHA yield reached 9.54 g/L, which was equivalent to that of traditional medium, while the cost of medium was reduced by 45% that achieved the recycle of food waste resource. Graphical abstract
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JOURNAL OF HAZARDOUS MATERIALS
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2022
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IF 14.224
Xingxing Peng,Tianyu Li,Qihang Zheng,Yingyuan Lu,Yuzhe He,Yetao Tang,Rongliang Qiu
Hexabromocyclododecane (HBCD) is a typical persistent organic pollutant that is widely detected in the environment. Despite the significant efforts put into its mineralisation , there is still a lack of microorganism resources that can completely mineralise HBCD. Stable isotope analysis revealed that the Citrobacter sp . Y3 can use [ 13 C]HBCD as its sole carbon source and degrade or even mineralise it into 13 CO 2 , with a maximum conversion rate of 100% in approximately 14 days. Strain Y3 could completely mineralise HBCD, which it used as its only carbon source, and six debromination enzymes related to HBCD degradation were found in Y3, including haloalkane dehalogenase (DhaA), haloacid dehalogenase (HAD), etc. A functional gene named HBCD-hd-1 , encoding a HAD, was found to be upregulated during HBCD degradation and heterologously expressed in Escherichia coli . Recombinant E. coli with the HBCD-hd-1 gene transformed the typical intermediate 4-bromobutyric acid to 4-hydroxybutanoic acid and showed excellent degradation performance on HBCD, accompanied by nearly 100% bromine (Br) ion generation. The expression of HBCD-hd-1 in Y3 rapidly accelerated the biodegradation of HBCD. With HBCD as its sole carbon source, strain Y3 could potentially degrade HBCD, especially in a low-nutrient environment.
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高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Ailin Zhang,Yanhua Hou,Quanfu Wang,Yatong Wang
Biotreatment of polyethylene (PE) waste is an emerging topic in environmental remediation; in particular, the degrading enzymes requires further exploration. This study described a novel cold-adapted laccase (PsLAC) from an Antarctic psychrophile and characterized its PE-degradation ability. Homology modeling revealed that PsLAC possessed a typical bacterial laccase catalytic structure and unique cold adaptation structural characteristics such as few hydrogen bonds . Recombinant PsLAC (rPsLAC) retained 54.3% residual activity at 0 ℃ and presented increased K m values at low temperatures and a relatively high k cat value (42.65 s −1 ). Collectively, these factors help resist cold stress. rPsLAC possessed substantial salt tolerance at 1.5 M NaCl, with 119.80% activity, and Cu 2+ enhanced its activity to 127.10%. PE-degradation experiments indicated that 13.2% weight was lost, and the water contact angle was decreased to 74.6°. Polar functional groups such as carbonyl and carboxyl groups on PE surface were detected in Fourier transform infrared spectroscopy ; X-ray diffraction exhibited that crystallinity reduced by 25%. Enormous damage to PE surface and interior was observed via scanning electron microscopy. Overall, PsLAC, with its unique cold-adapted catalytic structure and biochemical characteristics, could supplement the diversity of sources and properties of bacterial laccases and ensure PE-degradation with a novel cold-adapted enzyme resource.
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高影响因子
ENVIRONMENTAL MICROBIOLOGY
·
2021
·Vol. 23
·期 6
·3265-3273
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IF 5.491
Mingliang Zhang,Yijun Ren,Shilong Du,Yidong Zhou,Wankui Jiang,Zhijian Ke,Mingli Jiang,Jiguo Qiu,Jian He,Qing Hong
Summary Pymetrozine is a synthetic pesticide that can be utilized as the sole carbon source by Pseudomonas sp. strain BYT-1. However, the genes involved in the degradation of pymetrozine remain unknown. We used transposon mutagenesis to create a mutant that unable to hydrolyze pymetrozine. The transposon interrupted the gene pyzH , which was cloned by self-formed adaptor PCR. PyzH hydrolyzed the C=N double bond of pymetrozine to produce 4-amino-6-methyl-4,5-dihydro-2 H -[1,2,4]triazin-3-one (AMDT) and nicotinaldehyde; the latter inhibits PyzH activity. PyzH can completely hydrolyze pymetrozine in the presence of dehydrogenase ORF6, which can convert nicotinaldehyde into nicotinic acid and relieve the inhibition. H 2 18 O-labeling experiments showed that the oxygen atom of nicotinaldehyde came from water instead of oxygen. PyzH homologous genes were also found in other soil isolates able to degrade pymetrozine.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Wen-Jing Wei,Lei Li,Yu-Pei Gao,Qiang Wang,Yao-Yu Zhou,Xin Liu,Yuan Yang
Plants can absorb and accumulate engineered nanomaterials (ENMs) through water and soil, providing a potential way for nanoparticles to be enriched in humans through the food chain. In this paper, a combination of enzymatic digestion method and SP-ICP-MS analysis was used to quantitatively characterize the enriched AuNPs in mustard and lettuce plants. The results showed that Macerozyme R-10 enzyme can extract AuNPs from plants without obvious aggregation/dissolution. Both mustard and lettuce plants can absorb and enrich the complete AuNPs to the above-ground organs, and the particle number concentrations detected are 1.24 × 10 7 particles L −1 and 4.39 × 10 7 particles L −1 , respectively. With different exposure level of AuNPs(0.5 mg L −1 ,), a particle number concentration of 2.32 × 10 7 particles L −1 was detected in the stems of lettuce plants, while the mustard failed to transport AuNPs to the above-ground organs. The transport efficiency of Au ions by plants is higher than that of AuNPs, and the plants have stronger bioavailability for ions.
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JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Dong Hui Liang,Yongyou Hu
Little information is available regarding the kinetics, products, and pathways of simultaneous SMX degradation and Cd(II) immobilization from wastewater. In this study, a novel bacterium ( Achromobacter sp. L3) with SMX degradation and Cd(II) immobilization capabilities was isolated. The boundary conditions of SMX degradation were as follows: initial pH 6–8, temperature 25–30 °C, and SMX concentration 10–40 mg/L −1 . The boundary conditions of Cd(II) immobilization were as follows: initial pH 7–9, temperature 25–35 °C, and SMX concentration 10–30 mg/L −1 . The maximum SMX degradation and Cd(II) removal were 91.98% and 100%, respectively. The SMX degradation and Cd(II) immobilization data fitted well with the pseudo-first-order kinetic model, indicating that the two pollutants conform to the same degradation rule. Moreover, the microbial degradation , sediment adsorption, and intermediates identified in the experiments were used to explore the mechanisms of SMX and Cd(II) removal. These results indicate that microbial removal and sediment adsorption play equally important roles in Cd(II) immobilization; however, microbial degradation plays a decisive role in SMX degradation. Furthermore, the relationship between aerobic denitrification, SMX degradation, and Cd(II) immobilization was proposed. These results may provide valuable insights for treatment of wastewater polluted by antibiotics and heavy metals.
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INTERNATIONAL MICROBIOLOGY
·
2024
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IF 2.3
Chen Xueting,Zhang Yuping,Liu Jinghua
A novel enrofloxacin-degrading fungus was isolated from a rhizosphere sediment of the submerged macrophyte Vallisneria spiralis L.. The isolate, designated KC0924g, was identified as a member of the genus Humicola based on morphological characteristics and tandem conserved sequence analysis. The optimal temperature and pH for enrofloxacin degradation by strain KC0924g were 28 °C and 9.0, respectively. Under such condition, 98.2% of enrofloxacin with an initial concentration of 1 mg L −1 was degraded after 72 h of incubation, with nine possible degradation products identified. Four different metabolic pathways were proposed, which were initiated by cleavage of the piperazine moiety, hydroxylation of the aromatic ring, oxidative decarboxylation, or defluorination. In addition to enrofloxacin, strain KC0924g also degraded other fluoroquinolone antibiotics (ciprofloxacin, norfloxacin, and ofloxacin), malachite green (an illegal additive in aquaculture), and leucomalachite green. Pretreatment of cells of strain KC0924g with Cu 2+ accelerated ENR degradation. Furthermore, it was speculated that a flavin-dependent monooxygenase was involved in ENR degradation, based on the increased transcriptional levels of these two genes after Cu 2+ induction. This work enriches strain resources for enrofloxacin remediation and, more importantly, would facilitate studies on the molecular mechanism of ENR degradation with degradation-related transcriptome available.
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高影响因子
Frontiers in Microbiology
·
2016
·
IF 4.165
Yang Jie,Wang Guozeng,Ng Tzi Bun,Lin Juan,Ye Xiuyun
Laccases can oxidize a wide range of aromatic compounds and are industrially valuable. Laccases often exist in gene families and may differ from each other in expression and function. Quantitative real-time polymerase chain reaction (qPCR) was used for transcription profiling of eight laccase genes in Cerrena sp. strain HYB07 with validated reference genes. A high laccase activity of 280.0 U/mL was obtained after submerged fermentation for 5 days. Laccase production and laccase gene transcription at different fermentation stages and in response to various environmental cues were revealed. HYB07 laccase activity correlated with transcription levels of its predominantly expressed laccase gene, Lac7. Cu2+ ions were indispensable for efficient laccase production by HYB07, mainly through Lac7 transcription induction, and no aromatic compounds were needed. HYB07 laccase synthesis and biomass accumulation were highest with non-limiting carbon and nitrogen. Glycerol and inorganic nitrogen sources adversely impacted Lac7 transcription, laccase yields, and fungal growth. The present study would further our understanding of transcription regulation of laccase genes, which may in turn facilitate laccase production as well as elucidation of their physiological roles.
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高影响因子
APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2014
·Vol. 175
·期 5
·2647-2658
·
IF 1.687
He Yu-Cai,Liu Feng,Zhang Dan-Ping,Gao Shan,Li Zhi-Qing,Tao Zhi-Cheng,Ma Cui-Luan
In this study, it was the first report that Bacillus sp. CCZU11-1 was used for the biotransformation of 1,3-propanediol cyclic sulfate (1,3-PDS) and its derivatives. The catalytic performance of Bacillus sp. sulfatase in the biotransformation of 1,3-PDS was significantly improved by biocatalyst permeabilization and immobilization. Using cell permeabilization, the hydrolytic activity of the whole-cell biocatalyst was increased by 3.5-fold after 1.5 h of pretreatment with 10 % ( v / v ) toluene at 30 °C and pH 7.0. Biotransformation of 20 mM 1,3-PDS for 24 h, 1,3-propanediol (1,3-PD) could be obtained in the yield of 97.4 % under the optimized reaction condition. Additionally, the immobilized biocatalysts, permeabilized cells entrapped in calcium alginate, and cross-linked enzyme aggregates were further employed to biotansform 1,3-PDS. Moreover, the total operational time of the immobilized biocatalysts could reach above 240 h with high conversion rate (>90 %).
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ANALYTICAL LETTERS
·
2024
·
IF 1.6
Chaoying Zhang,Qin Zhang,Yingchun Zhao,Dianquan Dong,Longjiang Huang
Monitoring TiO2 nanoparticles (NPs) that are released from functional textiles is significant for assessing the potential risk to consumers. However, determining the size distribution of TiO2 NPs is still a challenge due to agglomeration. The present study employed single particle–inductively coupled plasma–mass spectrometry (SP-ICP-MS) to quantify TiO2 NPs released from functional textiles. Through screening dispersants and validating the standard samples, an accurate method for determining the size and number of TiO2 NPs was developed. The validated procedure was successfully used to determine the release of TiO2 NPs from yarn in sweat and water media throughout the day. The result revealed that the yarn decorated with TiO2 NPs released approximately the same particle size distribution from 60 to 260 nm in both media. The released particle concentration was 0.094 µg/mL with a mean size of 136 nm in water and a particle concentration of 0.120 µg/mL with a mean size of 133 nm in sweat. Additionally, based upon transmission electron microscopy, anatase TiO2 NPs were identified. It is expected that this work is significant in the evaluation of the toxicological effects of multifunctional textiles modified by TiO2 NPs on human health.
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BIORESOURCE TECHNOLOGY
·
2021
·
IF 9.642
Zeyu Wang,Luyao Dai,Jiachao Yao,Tianjiao Guo,Dzmitry Hrynsphan,Savitskaya Tatsiana,Jun Chen
Aiming at the accumulation of NO 2 − -N and N 2 O during denitrification process, this work focused to improve the denitrification performance by Pd-Fe embedded multi-walled carbon nanotubes (MWCNTs). The main conclusions were as follows: 30 mg/L Pd-Fe/MWCNTs have shown an excellent promotion on denitrification (completely TN removal at 36 h). Meanwhile, enzyme activity results indicated that the generation of NO 2 − -N, NH 4 + -N by Pd-Fe/MWCNTs led the occur of short-cut denitrification by increasing 203.9% the nitrite reductase activity. Furthermore, electrochemical results and index correlation analysis confirmed that the electron exchange capacity (1.401 mmol eg −1 ) of Pd-Fe/MWCNTs was positively related to nitrite reductase activity, indicating its crucial role in electron transport activity (0.46 μg O 2 /(protein·min) at 24 h) during denitrification process by Pd-Fe/MWCNTs played a role of chemical reductant and redox mediator.
研究领域:
环境工程
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生物技术
·
微生物学
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