BIOCHEMICAL ENGINEERING JOURNAL
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2021
·
IF 3.978
Shuiquan Chen,Meng Zang,Lin Li,Juntao Chen,Qiyou Liu,Xiwen Feng,Shuo Sun,Chuanwei Zang,Chaocheng Zhao
Biodesulfurization is a promising, environmentally friendly method to desulfurize the organosulfur compounds in crude oils through the highly selective cleavage of carbon-sulfur bonds under mild reaction conditions. In this study, the behavior of a hydrophobic bacterium, Gordonia sp. SC-10, was evaluated in the presence of diesel oils. The biodesulfurization pathways, bacterium hydrophobicity , and cell ultrastructure were investigated, and the capability of strain SC-10 to desulfurize diesel oil was also studied. The results showed that strain SC-10 can desulfurize organosulfur compounds through sulfur-specific desulfurization pathways by producing corresponding hydroxylated products in oil-water polyphasic systems. Mycolic acids consisting of 47 and 58 carbon atoms chains were produced on the cell surface, and inclusion bodies were produced in the cells, both of which may improve the bioavailability of the substrates, thereby enhancing its adaptability to oil-water polyphasic systems. To our knowledge, this is the first report of intracellular inclusion body formation during biodesulfurization. Strain SC-10 also exhibited broad substrate specificity towards organosulfur compounds and effectively desulfurized diesel oils. The sulfur content in real-life diesel oil was reduced from 167.7 mg/L to 19.7 mg/L, with 88.3% of sulfur removed after five days of biodesulfurization. This study showed that Gordonia sp. SC-10 can be effectively used for the biodesulfurization of diesel oils.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
·
IF 4.784
Zhang Yajuan,Duan Yajuan,Zhong Lingli,Li Zhoukun,Cui Zhongli,Huang Yan
The asymmetric reduction of prochiral ketones is a promising process for synthesis of optically active alcohols. The aldo-keto reductase (AKR) is an attractive candidate of biocatalyst, due to its high enantioselectivity and environmentally friendly reaction conditions. In this work, nine putative AKR encoding genes from Corallococcus sp. EGB were cloned and expressed in Escherichia coli . Of these produced enzymes (CoAKRs), CoAKR7 exhibited reductive activity to various ketones and ketoesters, especially very high activity toward ethyl 4-chloro-3-oxobutanoate (COBE) with NADPH as the coenzyme. The CoAKR7 was optimally active at pH 7.0 and 50 °C. The apparent K m and V max for COBE was 14.18 U/mg and 0.269 mM, respectively. Moreover, CoAKR7 catalyzed an anti-Prelog reduction of COBE to ( S )-ethyl-4-chloro-3-hydroxybutanoate (CHBE) with e.e. >99%. Enzyme-substrate-cofactor docking analysis elucidated the molecular mechanism of the substrate stereospecificity, providing basis for protein engineering of these enzymes for applications in the synthesis of valuable chemicals.
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ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2019
·
IF 4.527
Lin Li,Xianwei Shen,Chaocheng Zhao,Qiyou Liu,Xuwei Liu,Yanan Wu
A potent bacterial strain capable of degrading dibenzothiophene (DBT) was isolated and evaluated for its characteristics. The strain, designated as LKY-5, is rod-shaped, gram-negative, and occurs mainly in clusters. It was identified as belonging to the Pseudomonas genus based on the 16S rDNA sequence and phylogenic analysis. Determination of its DBT depletion efficiency by gas chromatography revealed that the isolate was able to completely degrade up to 100 mg L −1 DBT within 144 h. The pH values, DBT concentrations, and biomasses in the medium varied significantly in the initial 24 h. A biosurfactant produced by LKY-5 was extracted and identified as a di-rhamnolipid with the formula Rha-Rha-C 8 -C 8:1 by HPLC-ESI-MS/MS. There were 26 metabolites in the DBT degradation process. Pseudomonas sp. LKY-5 exhibited unusually high DBT degradation efficiency via multiple metabolic pathways. Compared with the reported 4S and Kodama pathways, two more expanded metabolic pathways for the degradation of DBT are proposed. The polycyclic aromatic sulfur heterocycles (PASHs) in diesel , such as C 1 -DBT, C 2 -DBT, C 3 -DBT, 4,6-DMDBT, and 2,4,6-TMDBT, can also be degraded with 28.2–42.3% efficiency. The results showed that LKY-5 is an excellent bacterial candidate for the bioremediation of PASH-contaminated sites and sediments.
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OCEAN ENGINEERING
·
2019
·
IF 2.73
Jiangfan Chang,Xiaoyan He,Xiuqin Bai,Chengqing Yuan
Biofilm formation is crucial for subsequent biofouling. Various factors can affect the biofilm formation. Here we report the influence of hydrodynamic shear force on adhesion morphology and biofilm conformation of Bacillus sp. on stainless steel by a flow cell system. Static, laminar and turbulent conditions were selected for this study. The applicability of this flow cell was evaluated by computational fluid dynamics (CFD). Stable wall shear stresses were successfully obtained. The results showed that the spatial distribution of bacteria changed from single-cell to cluster under the effect of shear force and the higher shear force created smoother and denser clusters. The different morphology of clusters under different flow conditions was mainly due to the increased nutrient supply to the clusters with the increase of flow velocity. Under the effect of shear force, Bacillus sp. could change the shape and increase the production of extracellular polymeric substance which could reduce the effect of shear force and enhance the connection and adhesion, respectively. Under low shear force, biofilm preferred to form irregular and complicated structure which could lead to the formation of tower like biofilm and inhibit the external mass transfer . The results could shed some light on biofilm control strategies.
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JOURNAL OF HAZARDOUS MATERIALS
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2018
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IF 6.434
Shanshan Sun,Haizhen Wang,Yuanzhi Chen,Jun Lou,Laosheng Wu,Jianming Xu
Mycobacterium sp. WY10 was a highly effective PAHs-degrading bacterium that can degrade phenanthrene (PHE, 100 mg L −1 ) completely within 60 h and 83% of pyrene (PYR, 50 mg L -1 ) in 72 h. In this study, ten and eleven metabolites, respectively, were identified in PHE and PYR degradation cultures, and a detailed PHE and PYR metabolism maps were constructed based on the metabolic results. The strain WY10 degraded PHE and PYR with initial dioxygenation mainly on 3,4- and 4,5-carbon positions, respectively. Thereafter, PYR degradation entered the PHE degradation pathway via the ortho -cleavage. It was observed that the “lower pathway” of PHE and PYR degradations were different. Based on the kinetics of residual metabolites, PHE was degraded in a dominant phthalate pathway and a minor salicylate pathway. However, both phthalate and salicylate pathways played important roles on PYR degradation. The WY10 genome revealed there were fifty-three genes related to PAHs degradations, including a complete gene set for PHE and PYR degradation via the phthalate pathway. The candidate gene/ORF, BOH72_19755, encoding salicylate synthase might contribute in the salicylate pathway.
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EXTREMOPHILES
·
2018
·Vol. 22
·期 3
·473-484
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IF 2
Chen Kun,Mo Qingshan,Liu Huan,Yuan Feiyan,Chai Haonan,Lu Fuping,Zhang Huitu
A psychrophilic extracellular protease was isolated from the marine bacterium Planococcus sp. M7 found in the deep-sea mud of the Southern Indian Ocean. The mature protease is about 43 kDa and contains 389 amino acids. Sequence alignment revealed that the protease whose catalytic triad was comprised of Ser224, Lys249, and Gln253 contains a catalytic module belonging to the serralysin-type protease family 41, and displays 46.55% identity with the experimentally verified serine protease from Bacillus subtilis str. 168. The enzyme displayed an alkaline mesophilic preference with an optimum pH of 10.0 and an optimum temperature of 35 °C. The enzyme retained its activity from 5 to 35 °C and was resistant to repeated freezing and thawing, but was completely inactivated at 55 °C. Calcium ions had a protective effect against thermal denaturation. More than 60% of the maximum activity was retained at pH values in the range of 5.0–11.0. Almost no activity loss was detected after 1 h of incubation at pH 8.0–10.0 and 20 °C, or with 1.0% SDS. Most important, this protease also showed good stability and compatibility with the standard enzyme-free detergent, which indicates its special interest for applications in detergent industry.
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Nature Communications
·
2024
·Vol. 15
·期 1
·1-15
·
IF 14.7
Tang Si,Cheng Xueyu,Liu Yaqing,Liu Lu,Liu Dai,Yan Qi,Zhu Jianming,Zhou Jin,Jiang Yuyang,Hammerschmidt Katrin,Cai Zhonghua
Diazotrophic cyanobacteria can fix nitrogen gas (N 2 ) but are usually scarce in nitrogen-limited coastal waters, which poses an apparent ecological paradox. One hypothesis is that high salinities (> 10 g/L NaCl) may inhibit cyanobacterial N 2 fixation. However, here we show that N 2 fixation in a unicellular coastal cyanobacterium exclusively depends on sodium ions and is inhibited at low NaCl concentrations (< 4 g/L). In the absence of Na + , cells of Cyanothece sp. ATCC 51142 (recently reclassified as Crocosphaera subtropica ) upregulate the expression of nifHDK genes and synthesise a higher amount of nitrogenase, but do not fix N 2 and do not grow. We find that the loss of N 2 -fixing ability in the absence of Na + is due to insufficient ATP supply. Additional experiments suggest that N 2 fixation in this organism is driven by sodium energetics and mixed-acid fermentation, rather than proton energetics and aerobic respiration, even though cells were cultured aerobically. Further work is needed to clarify the underlying mechanisms and whether our findings are relevant to other coastal cyanobacteria.
研究领域:
微生物学
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海洋生物学
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生物化学
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Polymers
·
2024
·Vol. 16
·期 5
·692
·
IF 4.7
Yi Mao,Yajuan Sun,Cheng Yang
A dual biofunctional hydrogel (HQCS-SP) wound dressing, offering antibacterial properties and a biological response, was innovatively designed and developed to repair full-layer skin defects. The HQCS-SP hydrogel creates an artificial matrix that facilitates cell recruitment, extracellular matrix deposition, exhibiting exceptional tissue affinity, robust self-healing, effective hemostatic capabilities and accelerates wound healing. It is synthesized by crosslinking modified chitosan (HQCS) with spirulina protein (SP) and Fe3+. The HQCS provides antibacterial, antioxidant, good tissue affinity and excellent hemostasis performance. The incorporation of SP not only reinforces the antioxidant, antibacterial, anti-inflammatory, and pro-angiogenesis effects but also participates in the regulation of signal pathways and promotes wound healing. Therefore, this study offers a new visual angle for the design of advanced functional trauma dressings with great application potential in the bio-medical field.
研究领域:
生物医学工程
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材料科学
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伤口愈合
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组织工程
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APPLIED AND ENVIRONMENTAL MICROBIOLOGY
·
2025
·
IF 3.7
Qi Zeng,Lili Jian,Songbiao Shi,Qiaoqiao Guo,Syed Raziuddin Quadri,Lijuan Long,Xinpeng Tian
Mangrove ecosystems are critical for coastal protection and biodiversity but are increasingly threatened by plastic pollution, particularly polyethylene terephthalate (PET). In this study, a novel marine bacterium, strain SCSIO 80796T, was isolated from PET debris collected from the mangrove in QiAo Island, Zhuhai, China. Using a polyphasic taxonomic approach, including 16S rRNA gene sequencing, genome-based comparisons (average nucleotide identity [ANI] 72.2%, digital DNA-DNA hybridization [dDDH] 19.0%, average amino acid identity [AAI] 70.6%), and phenotypic and chemotaxonomic analyses, the strain was classified as a novel species within the genus Neptunicella. It is proposed as Neptunicella plasticusilytica sp. nov. (type strain SCSIO 80796ᵀ = MCCC 1K08369T = KCTC 92826T). Genomic analysis revealed that strain SCSIO 80796ᵀ encodes a novel PET-degrading enzyme, NmCut, which degrades PET and yields 105–120 µM of degradation products [terephthalic acid (TPA), mono(2-hydroxyethyl) terephthalate (MHET), bis(2-hydroxyethyl) terephthalate (BHET)] within 48 h at 60°C. NmCut exhibits both structural and evolutionary novelty, featuring a unique PET-binding module (PBM) absent in known PETases. PBM is characterized by a long, positively charged α-helix enriched in aromatic residues, forming a distinct substrate-interacting surface with potential as a transferable domain to enhance the efficiency of other plastic-degrading enzymes. This study not only expands the known diversity within Neptunicella but also highlights the potential of marine-derived microbes in addressing plastic pollution through biotechnological applications.
研究领域:
海洋微生物学
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环境生物技术
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微生物分类学
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生物降解
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基因组学
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酶学
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POLYMER
·
2024
·
IF 4.1
Yanghang Liu,Heyu Zhang,Tao Zhang,Yuefei Ding,Siqi Zhang,Dan Yu,Wei Wang
Gas sensors are crucial in various applications such as environmental monitoring, industrial safety, and air quality control. However, many of these sensors still encounter significant challenges, including complex fabrication processes, low sensitivity, and poor stability. This study presents the development of a novel photochromic sensor using spiropyran (SP), waterborne polyurethane (WPU), and cellulose nanofiber (CNF) aerogel, aiming to overcome these challenges and provide highly sensitive detection of acidic gases. Under ultraviolet (UV) irradiation, the SP component in the aerogel isomerizes to its open-ring merocyanine (MC) form, which is further protonated to protonated merocyanine (MCH) in the presence of acid vapors. Systematic testing reveals that the SP/WPU/CNF aerogel sensor exhibits a rapid response time of 20 s under UV light irradiation and retains 75 % of its photoresponsivity after 20 cycles, demonstrating excellent durability. Additionally, the sensor exhibits a response time of 20 s to acidic gases, with a color change from purple to yellow when exposed to HCl gas at concentrations as low as 1 ppm. After undergoing five protonation and recovery cycles, the sensor maintains a certain level of acid responsiveness. These exceptional properties highlight the potential of the SP/WPU/CNF aerogel-based sensor to be a highly sensitive, efficient, and stable solution for acidic gas detection.
研究领域:
材料科学
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环境科学
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化学工程
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MOLECULES
·
2016
·Vol. 21
·期 8
·970
·
IF 2.465
Ying Han,Erli Tian,Dongbo Xu,Min Ma,Zixin Deng,Kui Hong
During our search for interesting bioactive secondary metabolites from mangrove actinomycetes, the strainStreptomycessp. 219807 which produced a high elaiophylin yield of 4486 mg/L was obtained. A new elaiophylin derivative, halichoblelide D (1), along with seven known analogues2–8was isolated and identified from the culture broth. Their chemical structures were determined by detailed analysis of 1D and 2D NMR and HRMS data. The absolute configuration of halichoblelide D (1) was confirmed by comparing the CD spectrum with those of the reported analogues. Compounds1–7exhibited potent cytotoxic activities against HeLa and MCF-7 cells with IC50values ranging from 0.19 to 2.12 μM.Keywords:mangrove actinomycetes;Streptomycessp. 219807;elaiophylin;cytotoxic
研究领域:
微生物学
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药物化学
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肿瘤学
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FOOD MICROBIOLOGY
·
2020
·
IF 4.155
Xianfeng Ye,Yang Chen,Shiyun Ma,Tian Yuan,Yaxuan Wu,Yingxuan Li,Yuqiang Zhao,Shuying Chen,Yiwen Zhang,Liuyan Li,Zhoukun Li,Yan Huang,Hui Cao,Zhongli Cui
Myxobacteria have excellent biocontrol activity against various phytopathogens due to their rich spectrum of secondary metabolites and active predatory characteristics. In this study, the mycelial growth of Fusarium oxysporum f. sp. cucumerinum (FOC) was found to be significantly inhibited by volatile compounds (VOCs) produced by Corallococcus sp. EGB. A total of 32 compounds were identified among the VOCs produced by strain EGB, of which isooctanol exhibited the highest antifungal activity , with dosages of 3.75 and 4.0 μL/plate being sufficient to suppress FOC and Penicillum digitatum , respectively. Isooctanol was found to damage the cell wall and cell membranes of FOC and P. digitatum . Apoptosis-like cell death of FOC and P. digitatum induced by isooctanol was observed subsequently due to the accumulation of reactive oxygen species (ROS). The transcription level of genes related to cell wall integrity (CWI) pathway and redox reactions were significantly upregulated by 15- to 40-fold, indicating the stress caused by isooctanol. Postharvest storage experiments showed that the disease severity of post-harvest oranges infected with P. digitatum could be significantly reduced by isooctanol at 114.2 μL/L.
研究领域:
微生物学
·
植物病理学
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植物化学
·
食品科学
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