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151.
Eight aerobic bacterial strains were isolated from pulp paper mill effluent sludge. Out of eight through nutrient enrichment technique three potential aerobic bacterial strains ITRC S(6), ITRC S(7) and ITRC S(8) were found capable to effectively degrade the kraft lignin (KL), a major byproduct of the chemical pulping process and main contributor to the colour and toxicity of effluent. Further, these potential strains (ITRC S(6), ITRC S(7) and ITRC S(8)) were biochemically characterised as Gram variable small rod, Gram negative rod and Gram positive rod respectively. Subsequently, 16S rRNA sequencing showed 95% base sequence homology and it was identified as Paenibacillus sp. (AY952466), Aneurinibacillus aneurinilyticus (AY856831), Bacillus sp. (AY952465) for ITRC S(6), IITRC S(7) and ITRC S(8), respectively. In batch decolourization experiments Bacillus sp. ITRC S(8) reduced the colour of lignin amended mineral salt medium, pH 7.6 by 65% after 6th d, at 30 degrees C, A. aneurinilyticus ITRC S(7) by 56% and Paenibacillus ITRC S(6) 43%. Under these conditions the three strains degraded the KL by 37%, 33% and 30%, respectively while the mixed culture of these three bacteria reduced colour by 69%, lignin by 40% and total substrate by 50% under same conditions. Biodegradation of the KL was not affected by low (<0.2 mg l(-1)) dissolved oxygen content; thus oxygen inhibition is more likely to be a metabolism-dependent event. Initially with 48 h incubation the decolourization was slow with decreased pH. Further incubation there was rapid decolourization with slight increase in pH at 6d compared with initial pH by increasing culture optical density. The lignin analysis from medium with HPLC indicated complete degradation rather than biotransformation with complete loss of absorbance peak at 280 nm. 相似文献
152.
Tillage, cropping systems, and nitrogen fertilizer source effects on soil carbon sequestration and fractions 总被引:4,自引:0,他引:4
Sainju UM Senwo ZN Nyakatawa EZ Tazisong IA Reddy KC 《Journal of environmental quality》2008,37(3):880-888
Quantification of soil carbon (C) cycling as influenced by management practices is needed for C sequestration and soil quality improvement. We evaluated the 10-yr effects of tillage, cropping system, and N source on crop residue and soil C fractions at 0- to 20-cm depth in Decatur silt loam (clayey, kaolinitic, thermic, Typic Paleudults) in northern Alabama, USA. Treatments were incomplete factorial combinations of three tillage practices (no-till [NT], mulch till [MT], and conventional till [CT]), two cropping systems (cotton [Gossypium hirsutum L.]-cotton-corn [Zea mays L.] and rye [Secale cereale L.]/cotton-rye/cotton-corn), and two N fertilization sources and rates (0 and 100 kg N ha(-1) from NH(4)NO(3) and 100 and 200 kg N ha(-1) from poultry litter). Carbon fractions were soil organic C (SOC), particulate organic C (POC), microbial biomass C (MBC), and potential C mineralization (PCM). Crop residue varied among treatments and years and total residue from 1997 to 2005 was greater in rye/cotton-rye/cotton-corn than in cotton-cotton-corn and greater with NH(4)NO(3) than with poultry litter at 100 kg N ha(-1). The SOC content at 0 to 20 cm after 10 yr was greater with poultry litter than with NH(4)NO(3) in NT and CT, resulting in a C sequestration rate of 510 kg C ha(-1) yr(-1) with poultry litter compared with -120 to 147 kg C ha(-1) yr(-1) with NH(4)NO(3). Poultry litter also increased PCM and MBC compared with NH(4)NO(3). Cropping increased SOC, POC, and PCM compared with fallow in NT. Long-term poultry litter application or continuous cropping increased soil C storage and microbial biomass and activity compared with inorganic N fertilization or fallow, indicating that these management practices can sequester C, offset atmospheric CO(2) levels, and improve soil and environmental quality. 相似文献
153.
Wazne M Jagupilla SC Moon DH Christodoulatos C Koutsospyros A 《Journal of environmental quality》2008,37(6):2125-2134
Batch leaching tests, qualitative and quantitative x-ray powder diffraction (XRPD) analyses, and geochemical modeling were used to investigate the leaching mechanisms of Cr(VI) from chromite ore processing residue (COPR) samples obtained from an urban area in Hudson County, New Jersey. The pH of the leaching solutions was adjusted to cover a wide range between 1 and 12.5. The concentration levels for total chromium (Cr) and Cr(VI) in the leaching solutions were virtually identical for pH values >5. For pH values <5, the concentration of total Cr exceeded that of Cr(VI) with the difference between the two attributed to Cr(III). Geochemical modeling results indicated that the solubility of Cr(VI) is controlled by Cr(VI)-hydrocalumite and Cr(VI)-ettringite at pH >10.5 and by adsorption at pH <8. However, experimental results suggested that Cr(VI) solubility is controlled partially by Cr(VI)-hydrocalumite at pH >10.5 and by hydrotalcites at pH >8 in addition to adsorption of anionic chromate species onto inherently present metal oxides and hydroxides at pH <8. As pH decreased to <10, most of the Cr(VI) bearing minerals become unstable and their dissolution contributes to the increase in Cr(VI) concentration in the leachate solution. At low pH ( <1.5), Cr(III) solid phases and the oxides responsible for Cr(VI) adsorption dissolve and release Cr(III) and Cr(VI) into solution. 相似文献
154.
Namrata Gururani Anjana Srivastava Anita Sharma Prakash Chandra Srivastava 《补救:环境净化治理成本、技术与工艺杂志》2020,30(4):49-55
This study explored the possibility of removing 4‐nitrophenol (4‐NP) and 2,4‐dichlorophenol (2,4‐DCP) from water by using a dead blue‐green algae, Nostoc sp., dried and untreated and dried and treated with iron (Fe‐treated with 0.1 M ferric chloride solution for 1 day). The Nostoc sp. untreated and Fe‐treated biomass were used to study the sorption and desorption of 4‐NP and 2,4‐DCP. The effects of solute concentration, ionic strength, and temperature on sorption and desorption in the presence of untreated and treated Nostoc sp. biomass were investigated. The Fe‐treated Nostoc sp. biomass sorbed higher amounts of both 4‐NP and 2,4‐DCP than the untreated biomass. The percent cumulative desorption decreased from 6.41% to 0.28% and 1.84% to 0.19%, respectively, for 4‐NP and 2,4‐DCP for the Fe‐treated biomass. Biosorption of 4‐NP and 2,4‐DCP onto untreated and Fe‐treated Nostoc sp. biomass conformed to Freundlich isotherms. Iron treatment of Nostoc sp. biomass increased the value of ln K from 8.07 to 8.59 for 4‐NP and from 8.04 to 8.51 for 2,4‐DCP but decreased their desorption. An increase in ionic strength (0.003–0.03) increased the biosorption of both substituted phenols and decreased their percent desorption. An increase in temperature in the range of 15–35°C decreased the sorption of 4‐NP and 2,4‐DCP onto both untreated and Fe‐treated Nostoc sp. biomass and increased their desorption, indicating that the biosorption of both substituted phenols onto untreated and Fe‐treated Nostoc sp. biomass was principally a physical process. The results of this study suggest that Fe‐treated dried Nostoc sp. biomass could be explored as an inexpensive and eco‐friendly material for the effective removal of these phenols and, potentially, other chemicals from industrial wastewater and contaminated groundwater. 相似文献
155.
Avijit Ghosh Sukanya Misra Ranjan Bhattacharyya Abhijit Sarkar Amit Kumar Singh Vikas Chandra Tyagi Ram Vinod Kumar Vijay Singh Meena 《Environmental science and pollution research international》2020,27(10):10160-10184
Rising global population would force farmers to amplify food production substantially in upcoming 3–4 decades. The easiest way to increase grain production is through expanding cropping area by clearing uncultivated land. This is attained by permitting deadly loss of carbon (C) stocks, jeopardizing ecosystem biodiversity and deteriorating environmental quality. We aim to propose key agronomical tactics, livestock management strategy and advance approaches for aquaculture to increase productivity and simultaneously reduce the environmental impacts of farming sector. For this, we considered three major sectors of farming, i.e. agriculture, fishery and dairy. We collected literatures stating approaches or technologies that could reduce GHG emission from these sectors. Thereafter, we synthesized strategies or options that are more feasible and accessible for inclusion in farm sector to reduce GHG emission. Having comprehensively reviewed several publications, we propose potential strategies to reduce GHG emission. Agronomic practices like crop diversification, reducing summer fallow, soil organic carbon sequestration, tillage and crop residue management and inclusion of N2-fixing pulses in crop rotations are some of those. Livestock management through changing animals’ diets, optimal use of the gas produced from manures, frequent and complete manure removal from animal housing and aquaculture management strategies to improve fish health and improve feed conversion efficiency could reduce their GHG emission footprint too. Adapting of effective and economic practices GHG emission footprint reduction potential of farming sector could make farming sector a C neutral enterprise. To overcome the ecological, technological and institutional barriers, policy on trade, tax, grazing practice and GHG pricing should be implemented properly. 相似文献
156.
Singh Namita Ashish Kumar Naresh Raghu H. V. Bhand Sunil Chandra Sudhir Sharma Pradeep Kumar 《Environmental Chemistry Letters》2019,17(2):1097-1103
Environmental Chemistry Letters - Aflatoxin M1 contamination in milk and dairy products is a major issue worldwide. Aflatoxin is a carcinogen that enters into the milk through animals feed. Here,... 相似文献
157.
A field experiment has been conducted with four systemic herbicides viz., butachlor [N-(butoxymethyl)-2-chloro-2',6'-diethyl-acetanilide], fluchloralin [N-(2-chloroethyl)-(2,6-dinitro-N-propyl-4-trifluoromethyl) aniline], oxadiazon [5-terbutyl-3-(2,4-dichloro-5-isopro poxyphenyl)-1,3,4-oxadiazol-2-one] and oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenyl)-4-(trifluoromethyl) benzene] at their recommended field rates (2.0, 1.5, 0.4 and 0.12kga.i.ha(-1), respectively) to investigate their effects on growth and activities of aerobic non-symbiotic N(2)-fixing bacteria and phosphate solubilizing microorganisms in relation to availability of nitrogen and phosphorus in the rhizosphere soils as well as yield of the rice crop (Oryza sativa L cv. IR-36). Application of herbicides, in general, highly stimulated the population and activities of the target microorganisms, which resulted in a greater amount of atmospheric nitrogen fixation and phosphate solubilization in the rhizosphere soils of the test crop. The greater microbial activities subsequently augmented the mineralization and availability of nitrogen and phosphorus in the soil solution, which in turn increased the yield of the crop. Among the herbicides, oxyfluorfen was most stimulative followed by fluchloralin and oxadiazon in augmenting the microbial activities in soil. Butachlor also accentuated the mineralization and availability of nitrogen due to higher incitement of non-symbiotic N(2)-fixing bacteria in paddy soil. The grain and straw yields of the crop were also significantly increased due to the application of oxyfluorfen (20.2% and 21%) followed by fluchloralin (13.1% and 15.4%) and butachlor (9.1% and 10.2%), respectively. 相似文献
158.
Kartick Chandra Pal Naba Kumar Mondal Soumendranath Chatterjee Tuhin Subhra Ghosh Jayanta Kumar Datta 《Environmental monitoring and assessment》2014,186(2):699-709
A new Gram-positive, nonpigmented, rod-shaped fluoride-tolerant bacterial strain, NM25, was isolated from waterlogged muddy field soil collected from the fluoride endemic area of Rampurhat II block (average fluoride in water, 4.7 mg/l, and in soil, 1.5 mg/kg) in Birbhum District, West Bengal, India. The study was undertaken to characterize the fluoride-tolerant bacterial isolate, to determine its role in bioaccumulation of fluoride, and to analyze the water and soil quality of the bacterial environment. The isolate was positive for catalase, lipase, urease, protease, oxidase, and H2S production, but negative for indole production, nitrate reduction, and Vogues–Proskauer test. The organisms were sensitive to recommended doses of ofloxacin, kanamycin, rifampicin, levofloxacin, vancomycin, gatifloxacin, gentamicin, doxycycline, streptomycin, and nalidixic acid but resistant to ampicillin. Based on the phenotypic characteristics, 16S rRNA gene sequence, and phylogenetic analysis, the bacterial isolate NM25 was identified as Bacillus flexus. The G+C content of the 16S rDNA was 53.14 mol%. This strain tolerated up to 20 % (w/v) NaCl in nutrient agar medium and was grown at the pH range 4–12. It reduced fluoride concentration up to 67.45 % and tolerated more than 1,500 ppm of fluoride in brain–heart infusion agar medium. 相似文献
159.
Chandra A Pandey KC 《Journal of environmental biology / Academy of Environmental Biology, India》2011,32(5):559-565
The aim of the present study is to identify and characterize lucerne lines resistance to weevil infestation. After three years of field screening for resistance to weevil infestation, 13 lines of lucerne were selected to assess the genotypic variations for lucerne weevil (Hypera postica Gyll.) at biochemical and molecular levels. Total phenols varied from 0.15 to 0.91 mg g (DM) in these genotypes. The highest trypsin (11.11 unit mg(-1) protein) and chymotrypsin (93.0 unit mg(-1) protein) inhibitors activities were recorded in G-1-02 and B-4-03 lines respectively, whereas highest alpha-amylases inhibitor activity (14.2 unit mg(-1) protein) in C-6-01. Zymogram patterns for trypsin inhibitor activity showed quantitative variations among the lines. In total 262 DNA fragments were generated when 45 deca-mer random primers were employed. Genetic variation in terms of genetic distance ranged from 0.65 to 0.85. Sequential Agglomerative Hierarchical and Nested (SAHN) clustering using the Un-weighted Pair Group Method with Arithmetic mean (UPGMA) algorithm yielded two clusters (cluster I and II) which converged at 72% similarity level. Cluster I contained most of the lines having low level of weevil infestation. High bootstrap values (>40) indicated the significance of nodes embodied in these two clusters. However, SDS-PAGE analysis of the leaf proteins of these 13 lines showed no major variations except minor difference in the protein bands of molecular weights between 14 to 20 kD. 相似文献
160.
Chandra R Sankhwar M 《Journal of environmental biology / Academy of Environmental Biology, India》2011,32(6):739-745
Pulp paper mill pollutants are the major source of aquatic contamination having metals, lignin and chlorophenols. Study was conducted to see the effect of these contaminants on antibiotic resistance pattern of isolated bacteria. Pulp paper effluents were evaluated for its physico-chemical properties i.e, BOD 72143 +/- 164.81 to 22.32 +/- 2.48, COD 213136 +/- 583.59 to 60.40 +/- 6.34, total phenol 386 +/- 71.24 to 0.43 +/- 0.0, lignin 26312 +/- 258.59 to 73.67 +/- 31.81and microbial quality i.e. K. pneumonae, S. typhi, S. faecalis, P. aeruginosa, E. coli, Ent. faecalis, A. hydrophila, B. subtilis, S. aureus, Y enterolitica and V vulrificus. Antibiotic sensitivity (10-30 microg), heavy metal resistance (100-1000 microg ml(-1)), lignin (1000-10,000 ppm) and pentachlorophenol (100-1000 ppm) tolerance of bacterial strains were assessed by seven classes of antibiotics. Eleven bacterial isolates were found multidrug resistant towards antibiotics, heavy metal, lignin and PCP. Out of 11 isolates, 90.9% were found resistant against eleven antibiotics which acquired 100% resistant in presence of heavy metal, lignin and chlorophenols. Results also revealed that concentration of lignin (50-350 ppm) and PCP (5-30 ppm) induced maximum growth (273-8050 cfu ml(-1)) of pathogenic bacteria in river water. 相似文献