Boyebennett9118

The aim of this study was to reveal the biodegradation characteristics and physiological response mechanism of a newly isolated bacterium to 2,4,6-trinitrotoluene (TNT) contamination. A Klebsiella variicola strain with high efficiency of TNT degradation was used as the test strain to analyze the changes in cell growth, morphology, and functional groups under different TNT concentrations (0, 100 mg⋅L-1) and the effects of TNT stress on the metabolic profile as revealed by non-targeted metabonomics. A TNT concentration of 100 mg L-1 caused a significant increase in the 5-day biochemical oxygen demand (BOD5) to 950 mg L-1, while the degradation rate of TNT reached 100% within 30 h after inoculation with Klebsiella variicola. Fourier transform infrared spectroscopy (FTIR) analysis showed changes in the characteristic peak of triamide by TNT treatment. Non-targeted metabonomics identified a total of 544 differentially produced metabolites under TNT treatment (252 upregulated and 292 downregulated), mainly lipids and lipid-like molecules. The metabolic pathways associated with amino acid biosynthesis and metabolism were the most significantly enriched pathways, and simultaneous detection showed that TNT was degraded to 4-amino-2,6-dinitrotoluene (DNT), 2-hydroxylamino-4,6-DNT, 2-amino-4,6-DNT, 2-amino-4-nitrotoluene, and 2,4-DNT. These results confirmed that Klebsiella variicola has a high tolerance to TNT and efficiently degrades it. The degradation mechanism involves TNT-induced accelerated amino acid biosynthesis, production of a protease to catalyze the TNT transformation, and the participation of the transformed TNT products in cell metabolism.Oxidation of a commonly-used β-lactam pharmaceutical, cefoperazone (CFPZ), was systematically investigated by anodic oxidation (AO), AO in presence of H2O2 electro-generation (AO-H2O2) and electro-Fenton (EF) processes with an activated carbon fiber cathode from the biodegradability viewpoint. The degradation and mineralization rates increased in a sequence of AO less then AO-H2O2 less then EF. Even CPFZ could be efficiently degraded in EF process, achieving complete CFPZ mineralization was rather difficult. Thereby, the biodegradability of the effluent after electrochemical pretreatment was examined to test the feasibility of the combination of electrochemical and biological processes. The results suggested that compared with AO and AO-H2O2, EF process could effectively transform the non-biodegradable CFPZ into biocompatible materials with a high BOD5/COD value (0.33 after 720 min), allowing the possible biotreatment for further remediation. This behavior was relatively accorded with the average oxidation state (AOS) results, evidencing the potential of EF process in enhancing the biodegradability of CFPZ. The determination of inorganic ions revealed that N in CFPZ molecular was oxidized into NH4+ and NO3- ions in EF process. Oxalic, succinic, oxamic, fumaric and formic acids were also formed. Besides, six aromatic by-products were qualified and a possible pathway involving hydrolysis, hydroxylation and decarboxylation during CFPZ mineralization was proposed.The study investigated biomass yield and the uptake of P and aluminum by switchgrass grown in a low-P soil amended with alum-P sludge and a conventional fertilizer, monoammonium phosphate (MAP), at rates of 9.7, 19.4, 29.1 and 38.8 mg P kg-1 dry soil. Potted soil (amended and control) units were seeded with pre-germinated switchgrass and harvested three times at 50-day intervals. Over the three growth cycles, P from alum-P sludge gradually became available. Amendment rate showed no significant effect on switchgrass biomass yield. P availability was greater for alum-P sludge than MAP and this may have been enhanced by the properties and activities of the plant root system. Aluminum (Al) uptake by switchgrass increased with the number of cycles, but did not differ significantly among treatments. selleck chemicals Cumulative Al uptake over the 3 cycles was greater for below-ground biomass than for above-ground biomass. Maximum P recovery efficiency of 28% was achieved at the 9.7 mg P kg soil-1 rate. These results demonstrate that alum-P sludge is an effective source of available P for cropping switchgrass in a high pH and low Olsen-P soil.Arsenic is a toxic metalloid that enters cells adventitiously via uptake systems for phosphate transporters, aquaglyceroporins (AQPs) or sugar permeases. However, transport of highly toxic methylarsenite (MAs(III)) and relatively nontoxic methylarsenate (MAs(V)) by bacterial AQPs has not been characterized. MAs(V) has a history of use as an herbicide. Here we used whole genome sequence analysis of AQPs in arsenic resistance (ars) operons. The aqp genes are frequently located next to MAs(III) resistance genes such as arsH, which suggests that they could be involved in MAs(III) uptake. Bacterial AQPs encoded by ars operons can be classified into two subgroups. One subgroup includes AqpS from the plant symbiont Sinorhizobium meliloti 1021. Our data suggests that AqpS has a substrate selectivity filter different from that of other bacterial AQPs. Both Escherichia coli GlpF and AqpS conduct MAs(III) efficiently, but GlpF conducts the MAs(V) anion poorly, so E. coli takes up MAs(V) inefficiently. In contrast, AqpS conducts MAs(V) under physiological conditions. A homology model of AqpS indicates that it has a substrate channel with a selectivity filter containing the nonpolar residue Val177 instead of the charged arginine residue found in other AQPs. While the selectivity filter in most AQPs prevents movement of anions, Val177 is predicted to allow movement of the MAs(V) anion through the channel. We propose that AqpS is a component of an MAs(III) resistance pathway in which MAs(III) enters cells of S. meliloti via AqpS, is oxidized by ArsH to MAs(V), which exits the cells via AqpS.The synthesis of acrylamide bonded sodium alginate (AM-SA) hydrogel and acrylamide/graphene oxide bonded sodium alginate (AM-GO-SA) nanocomposite hydrogel was successfully performed using the free radical method. The AM-SA and AM-GO-SA hydrogels were applied as composited adsorbents in crystal violet (CV) dye removal. The adsorption process experiments were performed discontinuously and the acquired data showed that the efficiency is more dependent on pH than other factors. The C-O, CO, and CC groups were detected in the produced hydrogels. The amount of surface area was computed to be 44.689 m2/g, 0.0392 m2/g, and 6.983 m2/g for GO, AM-SA, and AM-GO-SA nanocomposite hydrogel, respectively. The results showed that the experimental data follow the Redlich-Peterson isotherm model. Also, the maximum adsorption capacity of monolayer for CV dye adsorption was determined using AM-SA hydrogel and AM-GO-SA nanocomposite hydrogel 62.07 mg/g and 100.30 mg/g, respectively. In addition, the parameters RL, n, and E showed that the processes of adsorption of CV dye using both types of adsorbents are physical and desirable.