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Journal ArticleDOI: 10.1016/J.JHAZMAT.2020.124086

Combination of biochar and immobilized bacteria accelerates polyacrylamide biodegradation in soil by both bio-augmentation and bio-stimulation strategies.

05 Mar 2021-Journal of Hazardous Materials (Elsevier BV)-Vol. 405, pp 124086-124086
Abstract: Polyacrylamide (PAM) has been used extensively due to its well-known stable chemical properties, but limited information is available on the biodegradation of soil-containing PAM. In this work, sufficient degradation of PAM was achieved via the addition of the Klebsiella sp. PCX-biochar composite to PAM-containing soil, due to the synergic effect of bio-augmentation and bio-stimulation. The optimal degradation rate of 69.1% over 30-day period was observed under the following conditions: the addition of immobilized bacteria at 0.07 g/g, pH 6.6, and temperature at 38.0 °C. In this study, we showed that PAM was successfully hydrolyzed by amidase, and ammonia in the hydrolysis product was then oxidized by the nitrifying bacteria. The decrease of water-extractable organic carbon (WEOC) also demonstrated the chain cleavage in PAM. PAM was utilized as a carbon source not only by Klebsiella sp. PCX but also by some taxa from indigenous bacteria. Last but not least, it was shown in this study that biochar, even though immobilized with exogenous microorganisms, actually enhanced bacterial diversity and stimulated the growth of some indigenous PAM-degrading taxa. Based on the above observations, we concluded that PAM biodegradation via the addition of bacteria-immobilized biochar was a synergy of both bio-augmentation and bio-stimulation strategies.

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Topics: Biochar (55%), Biodegradation (53%), Nitrifying bacteria (51%)
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6 results found


Journal ArticleDOI: 10.1016/J.JECE.2021.105920
Abstract: Bioremediation is traditionally carried out using ‘free’ bacterial cells; however, in recent years, utilization of ‘immobilized’ bacterial cells has gained attention as a promising technique due to multifarious benefits. This review collates a vast amount of existing literature on the myriad contaminants treated using immobilized bacteria. We also discuss various mechanistic aspects of using immobilized cells for environmental remediation applications, with special attention on cells encapsulated in hydrogels and their implementation in detoxifying harmful contaminants and environmental cleanup. We examine different methods/techniques for immobilizing viable bacterial cells in various supporting matrices, use of single- and multi-species bacterial communities, various growth substrates, and factors affecting the remediation process including mass transfer, kinetic processes and bioreactor configurations used in pilot and field-scale applications. The advantages and limitations associated with the use of immobilized bacteria in a bioreactor for contaminated water treatment are also discussed. From a sustainable futures perspective, resource recovery and retrieval of value-added products along with bioremediation could be an added benefit of the immobilized cell-based treatment system, making it a more cost-effective and viable treatment strategy as well as one that is amenable to the principles of circular economy.

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Topics: Bioremediation (50%)

5 Citations


Open accessJournal ArticleDOI: 10.1155/2021/5582912
Yongni Wu1, Mengfan Yu1, Li Yanju1, Wu Yue1  +2 moreInstitutions (1)
Abstract: Three kinds of derivative carboxymethyl cellulose (DCMC) materials, CMC-Na, CMC-K, and CMC-NH4, were prepared from cotton straw fiber. Their chemical structure, film morphology, water retention, biodegradability, and growth promotion were investigated with infrared spectroscopy (IR), scanning electron microscope (SEM), and field experiments. The results showed that the infrared absorption peaks of the three materials were similar. It was observed that the DCMC materials could form films after being sprayed at the amount of 4.00 g/m2 and 12.00 g/m2, and the film thickness was showed in the order of CMC-K, CMC-NH4, and CMC-Na. The largest water holding capacity increased significantly after DCMC was sprayed on the soil. The water retention of CMC-Na, CMC-K, and CMC-NH4 increased by 47.74%, 72.85%, and 61.40% severally while sprayed with 12.00 g/m2 compared to the control group (CK), and the water retention rate increased with 6.93, 9.75, and 8.67 times, respectively, on the seventh day. The total number of soil microorganisms increased with the DCMC materials being sprayed; the number in the upper layer increased by 92.31%, 123.08%, and 138.46%, respectively, compared with CK. When the three materials were used to the cornfield at the amount of 100.00 kg/hm2, the corn yield increased by 33.11%, 70.93%, and 50.60%, respectively. The DCMC materials, as the sole carbon source, could be degraded by soil microorganisms. The nutrient elements such as NH4+ in the materials could further promote the growth of microorganisms and crops. This study might provide a new way to apply straw-based DCMC in soil water retention, soil amendment, and high value-added transformation of straws in arid areas.

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Topics: Carboxymethyl cellulose (51%)

1 Citations


Journal ArticleDOI: 10.1016/J.COLSURFA.2021.127011
Wenzhao Liu1, Changping Wang1, Bing Liu1, Jun Zhou1  +1 moreInstitutions (1)
Abstract: Stimuli-responsive hydrogels that can change their properties as a result of external stimuli have shown great promise in various applications, but it is still a great challenge to simultaneously provide hydrogels with excellent mechanical properties and significant response. Herein, we propose a facile synthesis of smart PAAm based hydrogels with highly elastic and swellable by introducing the activated nanoparticles into the hydrogel networks. Due to the heterogeneous microporous structure of the hydrogels, this material demonstrates the highly elastic property to withstand slicing and high level of compression and deformations, as well as significant swelling ratio (~5500%). Moreover, photonic hydrogel elastomers are fabricated by incorporating monodispersed SiO2@PS microspheres within this hydrogel elastomer matrix. The as formed materials possess structural color and the highly elasticity enables their good mechanochromic capability. Our strategy is a straightforward way to design smart hydrogels whose response and mechanical properties can be tuned through the judicious choice of the polymerization time and content of activated nanogel, extending the potential application of hydrogels.

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Topics: Self-healing hydrogels (69%), Nanogel (54%)

Journal ArticleDOI: 10.1016/J.JHAZMAT.2021.125942
Huang Jiaqing, Liu Cenwei, G.W. Price1, Yanchun Li  +1 moreInstitutions (1)
Abstract: A novel Ralstonia Bcul-1 strain was isolated from soil samples that was closest to Ralstonia pickettii. Broad-spectrum resistance was identified to a group of heavy metal ions and tolerance to concentrations of Cd2+ up to 400 mg L-1. Low concentrations of heavy metal ions did not have distinctive impact on heavy metal resistance genes and appeared to induce greater expression. Under exposure to Cd2+, cell wall components were significantly enhanced, and some proteins were also simultaneously expressed allowing the bacteria to adapt to the high Cd2+ living environment. The maximum removal rate of Cd2+ by the Ralstonia Bcul-1 strain was 78.97% in the culture medium supplemented with 100 mg L-1 Cd2+. Ralstonia Bcul-1 was able to survive and grow in a low nutrient and cadmium contaminated (0.42 mg kg-1) vegetable soil, and the cadmium removal rate was up to 65.76% in 9th growth. Ralstonia Bcul-1 mixed with biochar could maintain sustainable growth of this strain in the soil up to 75 d and the adsorption efficiency of cadmium increased by 16.23–40.80% as compared to biochar application alone. Results from this work suggests that Ralstonia Bcul-1 is an ideal candidate for bioremediation of nutrient deficient heavy metal contaminated soil.

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Topics: Ralstonia pickettii (68%), Ralstonia (58%), Cadmium (54%) ... show more

Open accessJournal ArticleDOI: 10.1016/J.ETI.2021.102059
Abstract: Microbial degradation is one of the effective methods to remove thifensulfuron-methyl (TSM) in soil and water environments. In this study, a high-efficiency TSM degrading strain Serratia marcecens N80 was used. The abandoned fungus substrate was converted to biochars at various pyrolysis temperatures (300, 450 and 600 °C). Biochar made at 600 °C (BC600) showed the best TSM adsorption capacity, while strain N80 adsorption efficiency reached the maximum up to 81.08%. Therefore, BC600, polyvinyl alcohol (PVA), and sodium alginate (SA) were chosen to establish an immobilized system for strain N80. The immobilized N80 beads (IN80) showed significantly improved reusability and storage stability. Under the optimal condition (pH 7.0, 35 °C, 1.5 × 10 8 cfu/mL), TSM (50 mg/L) degradation rates by free N80 and IN80 were 83.47 and 89.37% within 48 h, respectively. Free N80 and IN80 accelerated TSM degradation in soil, reducing its half-life to 6.13 d and 4.36 d, respectively. However, immobilized material beads (IM) slightly delayed the soil TSM degradation. TSM activated catalase and dehydrogenase but inhibited invertase and urease. IN80 treatment accelerated the recovery of invertase and urease. Moreover, IN80 accelerated the recovery of bacterial and fungal populations; the beneficial genera inhibited by TSM such as Sphingomonas, Lysobacter, Massilia, Rhodanobacter, and Gemmatimonas also increased to varying degrees. Meanwhile, IN80 showed an excellent inhibitory effect on pathogenic fungi (Fusarium and Alternaria), while increased the relative abundance of Mortierella, and the soil resistance to diseases. This study offers a potential in situ remediation strategy to improve the quality of the soil environment.

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73 results found


Open accessJournal ArticleDOI: 10.1038/NMETH.F.303
11 Apr 2010-Nature Methods
Abstract: Supplementary Figure 1 Overview of the analysis pipeline. Supplementary Table 1 Details of conventionally raised and conventionalized mouse samples. Supplementary Discussion Expanded discussion of QIIME analyses presented in the main text; Sequencing of 16S rRNA gene amplicons; QIIME analysis notes; Expanded Figure 1 legend; Links to raw data and processed output from the runs with and without denoising.

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24,116 Citations


Open accessJournal ArticleDOI: 10.1101/GR.1239303
Paul Shannon1, Andrew Markiel, Owen Ozier, Nitin S. Baliga  +5 moreInstitutions (1)
01 Nov 2003-Genome Research
Abstract: Cytoscape is an open source software project for integrating biomolecular interaction networks with high-throughput expression data and other molecular states into a unified conceptual framework. Although applicable to any system of molecular components and interactions, Cytoscape is most powerful when used in conjunction with large databases of protein-protein, protein-DNA, and genetic interactions that are increasingly available for humans and model organisms. Cytoscape's software Core provides basic functionality to layout and query the network; to visually integrate the network with expression profiles, phenotypes, and other molecular states; and to link the network to databases of functional annotations. The Core is extensible through a straightforward plug-in architecture, allowing rapid development of additional computational analyses and features. Several case studies of Cytoscape plug-ins are surveyed, including a search for interaction pathways correlating with changes in gene expression, a study of protein complexes involved in cellular recovery to DNA damage, inference of a combined physical/functional interaction network for Halobacterium, and an interface to detailed stochastic/kinetic gene regulatory models.

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Topics: Interaction network (60%), ConsensusPathDB (55%), Human interactome (53%) ... show more

23,868 Citations


Open accessJournal ArticleDOI: 10.1093/BIOINFORMATICS/BTR381
01 Aug 2011-Bioinformatics
Abstract: Motivation: Chimeric DNA sequences often form during polymerase chain reaction amplification, especially when sequencing single regions (e.g. 16S rRNA or fungal Internal Transcribed Spacer) to assess diversity or compare populations. Undetected chimeras may be misinterpreted as novel species, causing inflated estimates of diversity and spurious inferences of differences between populations. Detection and removal of chimeras is therefore of critical importance in such experiments. Results: We describe UCHIME, a new program that detects chimeric sequences with two or more segments. UCHIME either uses a database of chimera-free sequences or detects chimeras de novo by exploiting abundance data. UCHIME has better sensitivity than ChimeraSlayer (previously the most sensitive database method), especially with short, noisy sequences. In testing on artificial bacterial communities with known composition, UCHIME de novo sensitivity is shown to be comparable to Perseus. UCHIME is >100× faster than Perseus and >1000× faster than ChimeraSlayer. Contact: [email protected] Availability: Source, binaries and data: http://drive5.com/uchime. Supplementary information:Supplementary data are available at Bioinformatics online.

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9,879 Citations


Journal ArticleDOI: 10.1016/J.SOILBIO.2011.02.005
Andrew R. Zimmerman1, Bin Gao1, Mi-Youn Ahn1Institutions (1)
Abstract: Pyrogenic carbon (biochar) amendment is increasingly discussed as a method to increase soil fertility while sequestering atmospheric carbon (C). However, both increased and decreased C mineralization has been observed following biochar additions to soils. In an effort to better understand the interaction of pyrogenic C and soil organic matter (OM), a range of Florida soils were incubated with a range of laboratory-produced biochars and CO 2 evolution was measured over more than one year. More C was released from biochar-amended than from non-amended soils and cumulative mineralized C generally increased with decreasing biomass combustion temperature and from hardwood to grass biochars, similar to the pattern of biochar lability previously determined from separate incubations of biochar alone. The interactive effects of biochar addition to soil on CO 2 evolution (priming) were evaluated by comparing the additive CO 2 release expected from separate incubations of soil and biochar with that actually measured from corresponding biochar and soil mixtures. Priming direction (positive or negative for C mineralization stimulation or suppression, respectively) and magnitude varied with soil and biochar type, ranging from −52 to 89% at the end of 1 year. In general, C mineralization was greater than expected (positive priming) for soils combined with biochars produced at low temperatures (250 and 400 °C) and from grasses, particularly during the early incubation stage (first 90 d) and in soils of lower organic C content. It contrast, C mineralization was generally less than expected (negative priming) for soils combined with biochars produced at high temperatures (525 and 650 °C) and from hard woods, particularly during the later incubation stage (250–500 d). Measurements of the stable isotopic signature of respired CO 2 indicated that, for grass biochars at least, it was predominantly pyrogenic C mineralization that was stimulated during early incubation and soil C mineralization that was suppressed during later incubation stages. It is hypothesized that the presence of soil OM stimulated the co-mineralization of the more labile components of biochar over the short term. The data strongly suggests, however, that over the long term, biochar–soil interaction will enhance soil C storage via the processes of OM sorption to biochar and physical protection.

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Topics: Biochar (69%), Slash-and-char (62%), Mineralization (soil science) (58%) ... show more

975 Citations


Journal ArticleDOI: 10.1007/S00374-008-0334-Y
Abstract: The number of studies on priming effects (PE) in soil has strongly increased during the last years. The information regarding real versus apparent PE as well as their mechanisms remains controversial. Based on a meta-analysis of studies published since 1980, we evaluated the intensity, direction, and the reality of PE in dependence on the amount and quality of added primers, the microbial biomass and community structure, enzyme activities, soil pH, and aggregate size. The meta-analysis allowed revealing quantitative relationships between the amounts of added substrates as related to microbial biomass C and induced PE. Additions of easily available organic C up to 15% of microbial biomass C induce a linear increase of extra CO2. When the added amount of easily available organic C is higher than 50% of the microbial biomass C, an exponential decrease of the PE or even a switch to negative values is often observed. A new approach based on the assessment of changes in the production of extracellular enzymes is suggested to distinguish real and apparent PE. To distinguish real and apparent PE, we discuss approaches based on the C budget. The importance of fungi for long-term changes of SOM decomposition is underlined. Priming effects can be linked with microbial community structure only considering changes in functional diversity. We conclude that the PE involves not only one mechanism but a succession of processes partly connected with succession of microbial community and functions. An overview of the dynamics and intensity of these processes as related to microbial biomass changes and C and N availability is presented.

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907 Citations


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