共查询到19条相似文献，搜索用时 546 毫秒
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PVA及其复合材料生物降解研究进展 总被引：5，自引：0，他引：5
作为一种有着广泛用途的水溶性高分子材料，聚乙烯醇（PVA）及其衍生物的生物降解性能获得了越来越多的关注。在微生物驯化环境中，PVA具有生物降解的潜力。本文综述了PVA生物降解的机理、影响因素、降解性的评价方法以及降解环境对PVA降解性的影响，并对近年来基于PVA的共聚/共混材料的制备及其生物降解性能的研究进行了较为详细的概述。 相似文献
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目的：研究不同取代羧甲基壳聚糖（CMC）的生物降解性。方法：通过体外酶解试验，用粘度测定法研究了在溶菌酶作用下CMC的分子量。结果：溶菌酶作为催化CMC降解的非专一性酶，能有效地催化CMC降解；酶解反应程度与酶浓度成线性关系；随着羧甲基壳聚糖取代度的增加，CMC的降解速度加快。结论：通过控制取代度，可以得到不同生物降解要求的羧甲基壳聚糖。 相似文献
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地下水MTBE的污染及生物降解技术研究进展 总被引：1，自引：0，他引：1
甲基叔丁基醚(MTBE)被广泛用作汽油添加剂.因此其通过各种途径进入环境的数量不断增加;由于MTBE水溶性较强,在地下水中扩散速度很快,可在地下水中造成持久性的危害,对地下水构成了潜在的污染;而MTBE具有人体可疑致癌性,因此,研究MTBE的环境污染问题及降解修复技术具有重要的现实意义.本文综述了国外有关地下水中MTBE的监测调查结果及污染状况,对MTBE的微生物-植物等生物降解技术研究进展进行了归纳,为国内开展MTBE的污染防治研究及指导MTBE的安全使用提供理论依据. 相似文献
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日益增加的厨余垃圾严重影响着城镇环境,为获得用于家庭厨余垃圾微生物降解原位消除技术的功能菌株,本文通过溶菌圈和菌落直径观察以及胞外酶活性测定,证明本实验室分离、保藏的一株丝状真菌No.1对蛋白质、淀粉具有很强的降解能力并能有效降解纤维素和脂肪;通过18S rDNA的PCR扩增和序列测定,并与GenBank中核酸数据比对分析,表明该菌株与Actinomucor elegans(AY243955)同源性达99%,故将其鉴定为雅致放射毛霉(Actinomucor elegans sp.). 相似文献
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多环芳烃污染已成为重要的环境问题,为人类健康带来了严重的不良影响。多环芳烃在环境中的降解主要依赖于微生物,微生物通过自身的代谢将其降解为低毒性的产物或者二氧化碳。本文就降解多环芳烃的微生物种类、好氧及厌氧降解途径、强化微生物降解方法进行了概述,并展望了今后的研究趋势,旨在为更好地利用微生物降解多环芳烃提供理论依据。 相似文献
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BackgroundThe hydrolysis of keratin wastes by microorganisms is considered a biotechnological alternative for recycling and valorization through keratinolytic microorganisms. Despite their resistant structure, keratin wastes can be efficiently degraded by various microorganisms through the secretion of keratinases, which are promising enzymes for several applications, including detergents, fertilizers, and leather and textile industry. In an attempt to isolate keratinolytic microorganisms that can reach commercial exploitation as keratinase producers, the current work assesses the dynamics of keratin biodegradation by several keratinolytic fungal strains isolated from soil. The activity of fungal strains to degrade keratin substrates was evaluated by SEM, FTRIR-ATR spectra and TGA analysis.ResultsSEM observations offered relevant information on interactions between microorganism and structural elements of hair strands. FTIR spectra of the bands at 1035–1075 cm-1 assigned to sulfoxide bond appeared because of S–S bond breaking, which demonstrated the initiation of keratin biodegradation. According to TGA, in the second zone of thermal denaturation, where keratin degradation occurs, the highest weight loss of 71.10% was obtained for sample incubated with Fusarium sp. 1A.ConclusionsAmong the tested strains, Fusarium sp. 1A was the most active organism in the degradation process with the strongest denaturation of polypeptide chains. Because keratinolytic microorganisms and their enzymes keratinases represent a subject of scientific and economic interest because of their capability to hydrolyze keratin, Fusarium sp. 1A was selected for further studies. 相似文献
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Hierarchically porous monoliths based on copper (Cu), cobalt (Co) and manganese (Mn) oxides with three-dimensionally (3D) interconnected macropores and open nanopores were prepared using metal bromides as precursors via a sol–gel process accompanied by phase separation. The difficulty of gelation for low-valence metal cation was overcome by introducing a highly electronegative Br atom near to the metal atom to control the rates of hydrolysis and polycondensation. The 3D interconnected macropores were obtained using appropriate polymers to induce phase separation. The domain sizes of macropores and skeletons can be controlled by reaction parameters such as concentration and/or average molecular weight of polymers, and the amount of hydrochloric acid. The crystalline metal oxide monoliths with their 3D interconnected macroporous structure preserved were obtained after heat treatment in air. 相似文献
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BackgroundQuizalofop-p-ethyl (QPE), a unitary R configuration aromatic oxyphenoxypropionic acid ester (AOPP) herbicide, was widely used and had led to detrimental environmental effects. For finding the QPE-degrading bacteria and promoting the biodegradation of QPE, a series of studies were carried out.ResultsA QPE-degrading bacterial strain YC-XJ1 was isolated from desert soil and identified as Methylobacterium populi, which could degrade QPE with methanol by cometabolism. Ninety-seven percent of QPE (50 mg/L) could be degraded within 72 h under optimum biodegradation condition of 35°C and pH 8.0. The maximum degradation rate of QPE was 1.4 mg/L/h, and the strain YC-XJ1 exhibited some certain salinity tolerance. Two novel metabolites, 2-hydroxy-6-chloroquinoxaline and quinoxaline, were found by high-performance liquid chromatography/mass spectroscopy analysis. The metabolic pathway of QPE was predicted. The catalytic efficiency of strain YC-XJ1 toward different AOPPs herbicides in descending order was as follows: haloxyfop-p-methyl ≈ diclofop-methyl ≈ fluazifop-p-butyl > clodinafop-propargyl > cyhalofop-butyl > quizalofop-p-ethyl > fenoxaprop-p-ethyl > propaquizafop > quizalofop-p-tefuryl. The genome of strain YC-XJ1 was sequenced using a combination of PacBio RS II and Illumina platforms. According to the annotation result, one α/β hydrolase gene was selected and named qpeh1, for which QPE-degrading function has obtained validation. Based on the phylogenetic analysis and multiple sequence alignment with other QPE-degrading esterases reported previously, the QPEH1 was clustered with esterase family V.ConclusionM. populi YC-XJ1 could degrade QPE with a novel pathway, and the qpeh1 gene was identified as one of QPE-degrading esterase gene.How to cite: Li X, Wang J, Wu W, et al. Co-metabolic biodegradation of quizalofop-p-ethyl by Methylobacterium populi YC-XJ1 and identification of QPEH1 esterase. Electron J Biotechnol 2020;46. https://doi.org/10.1016/j.ejbt.2020.05.003. 相似文献
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BackgroundThe potential waste canola oil-degrading ability of the cold-adapted Antarctic bacterial strain Rhodococcus sp. AQ5-07 was evaluated. Globally, increasing waste from food industries generates serious anthropogenic environmental risks that can threaten terrestrial and aquatic organisms and communities. The removal of oils such as canola oil from the environment and wastewater using biological approaches is desirable as the thermal process of oil degradation is expensive and ineffective.ResultsRhodococcus sp. AQ5-07 was found to have high canola oil-degrading ability. Physico-cultural conditions influencing its activity were studied using one-factor-at-a-time (OFAT) and statistical optimisation approaches. Considerable degradation (78.60%) of 3% oil was achieved by this bacterium when incubated with 1.0 g/L ammonium sulphate, 0.3 g/L yeast extract, pH 7.5 and 10% inoculum at 10°C over a 72-h incubation period. Optimisation of the medium conditions using response surface methodology (RSM) resulted in a 9.01% increase in oil degradation (87.61%) when supplemented with 3.5% canola oil, 1.05 g/L ammonium sulphate, 0.28g/L yeast extract, pH 7.5 and 10% inoculum at 12.5°C over the same incubation period. The bacterium was able to tolerate an oil concentration of up to 4.0%, after which decreased bacterial growth and oil degradation were observed.ConclusionsThese features make this strain worthy of examination for practical bioremediation of lipid-rich contaminated sites. This is the first report of any waste catering oil degradation by bacteria originating from Antarctica.How to cite: Ibrahim S, Zahri KNM, Convey P, et al. Optimisation of biodegradation conditions for waste canola oil by cold-adapted Rhodococcus sp. AQ5-07 from Antarctica. Electron J Biotechnol 2020;48. https://doi.org/10.1016/j.ejbt.2020.07.005 相似文献
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BackgroundBiomineralization is a significant process performed by living organisms in which minerals are produced through the hardening of biological tissues. Herein, we focus on calcium carbonate precipitation, as part of biomineralization, to be used in applications for environmental protection, material technology, and other fields. A strain GM-1, Microbacterium sp. GM-1, isolated from active sludge, was investigated for its ability to produce urease and induce calcium carbonate precipitation in a metabolic process.ResultsIt was discovered that Microbacterium sp. GM-1 resisted high concentrations of urea up to 60 g/L. In order to optimize the calcification process of Microbacterium sp. GM-1, the concentrations of Ni2 + and urea, pH value, and culture time were analyzed through orthogonal tests. The favored calcite precipitation culture conditions were as follows: the concentration of Ni2 + and urea were 50 μM and 60 g/L, respectively, pH of 10, and culture time of 96 h. Using X-ray diffraction analysis, the calcium carbonate polymorphs produced by Microbacterium sp. GM-1 were proven to be mainly calcite.ConclusionsThe results of this research provide evidence that Microbacterium sp. GM-1 can biologically induce calcification and suggest that strain GM-1 may play a potential role in the synthesis of new biominerals and in bioremediation or biorecovery. 相似文献
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Cara Young Kester Rozario Christophe Serra Laura Poole-Warren Penny Martens 《Biomicrofluidics》2013,7(4)
Biosynthetic microspheres have the potential to address some of the limitations in cell microencapsulation; however, the generation of biosynthetic hydrogel microspheres has not been investigated or applied to cell encapsulation. Droplet microfluidics has the potential to produce more uniform microspheres under conditions compatible with cell encapsulation. Therefore, the aim of this study was to understand the effect of process parameters on biosynthetic microsphere formation, size, and morphology with a co-flow microfluidic method. Poly(vinyl alcohol) (PVA), a synthetic hydrogel and heparin, a glycosaminoglycan were chosen as the hydrogels for this study. A capillary-based microfluidic droplet generation device was used, and by varying the flow rates of both the polymer and oil phases, the viscosity of the continuous oil phase, and the interfacial surface tension, monodisperse spheres were produced from ∼200 to 800 μm. The size and morphology were unaffected by the addition of heparin. The modulus of spheres was 397 and 335 kPa for PVA and PVA/heparin, respectively, and this was not different from the bulk gel modulus (312 and 365 for PVA and PVA/heparin, respectively). Mammalian cells encapsulated in the spheres had over 90% viability after 24 h in both PVA and PVA/heparin microspheres. After 28 days, viability was still over 90% for PVA-heparin spheres and was significantly higher than in PVA only spheres. The use of biosynthetic hydrogels with microfluidic and UV polymerisation methods offers an improved approach to long-term cell encapsulation. 相似文献
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基于“驱动力-压力-状态-响应”（DPSR）模型构建生态城市建设水平评价指标体系,利用主成分分析法（PCA）计算指标权重对南京生态城市建设水平进行评价;同时,运用灰色关联模型（GRA）分析南京三次产业及产业内部结构对生态城市建设造成的影响。研究结果显示：2007－2016年间,南京生态城市建设水平除部分年份综合得分变动幅度明显较小外,总体上处于上升趋势;第一二三次产业对生态城市建设均存在重要影响,其中第三产业关联最大,其次为第一产业和第二产业;第一产业内部农业及农林牧渔服务业关联度较大,第二产业中工业关联度有所提升,建筑业关联度较低,第三产业中金融业、其他服务业等关联度较大,住宿餐饮业和交通运输业关联度较低。为推动南京生态城市建设,未来应进一步采取优化产业结构、对第一二三次产业内部进行取长补短的提升、加大环境治理的科技水平等措施。 相似文献
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Ana Nikler Helena i
ak Danijela Bejuk Vanja Radi&#x;i&#x; Biljak Ana-Maria &#x;imundi&#x; 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2022,32(1)
IntroductionThe aims of study were to assess: 1) performance specifications of Atellica 1500, 2) comparability of Atellica 1500 and Iris, 3) the accuracy of both analysers in their ability to detect bacteria.Materials and methodsCarryover, linearity, precision, reproducibility, and limit of blank (LoB) verification were evaluated for erythrocyte and leukocyte counts. ICSH 2014 protocol was used for estimation of carryover, CLSI EP15-A3 for precision, and CLSI EP17 for LoB verification. Comparison for quantitative parameters was evaluated by Bland-Altman plot and Passing-Bablok regression. Qualitative parameters were evaluated by Weighted kappa analysis. Sixty-five urine samples were randomly selected and sent for urine culture which was used as reference method to determine the accuracy of bacteria detection by analysers.ResultsAnalytical specifications of Atellica 1500 were successfully verified. Total of 393 samples were used for qualitative comparison, while 269 for sediment urinalysis. Bland-Altman analysis showed statistically significant proportional bias for erythrocytes and leukocytes. Passing-Bablok analysis for leukocytes pointed to significant constant and minor proportional difference, while it was not performed for erythrocytes due to significant data deviation from linearity. Kappa analysis resulted in the strongest agreements for pH, ketones, glucose concentrations and leukocytes, while the poorest agreement for bacteria. The sensitivity and specificity of bacteria detection were: 91 (59-100)% and 76 (66-87)% for Atellica 1500 and 46 (17-77)% and 96 (87-100)% for Iris.ConclusionThere are large differences between Atellica 1500 and Iris analysers, due to which they are not comparable and can not be used interchangeably. While there was no difference in specificity of bacteria detection, Iris analyser had greater sensitivity. 相似文献
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基于Moran’s I分析方法的耕地质量空间差异研究 总被引：2，自引：0，他引：2
本文引入Moran's I指数的空间自相关分析法,以广东省广宁县为例,以表征耕地质量的自然等指数、利用等指数和等别指数为空间变量,以耕地图斑为单元进行空间自相关分析,探讨Moran's I值的空间差异特征,以及在县级和乡镇级尺度上的变化情况及其相关应用。结果表明：①不同类型耕地质量指数在同一空间尺度上,均表现出较强的空间正相关性,自然等指数具有较强的空间正相关性,聚集程度较高,等别指数次之,利用等指数较弱,空间格局上相对较为分散;②不同的空间尺度,耕地质量指数具有不同的空间关联度。县级尺度空间自相关水平普遍高于镇级平均空间自相关水平;而且从镇级数据来看,大部分乡镇的Moran's I值均低于县级整体水平;③基于Moran's I值的耕地质量类别划分,通过引入空间权重刻画耕地质量空间分布特征,将其空间关联性作为“第四维”纳入到分区评价因素中,可为耕地保护分区提供新思路。 相似文献