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991.
The accelerating effect of quinones has been studied in the bio-decolorization processes, but there are no literatures about
the incorporation bio-treatment technology of the bromoamine acid (BA) wastewater and azo dyes wastewaters under high-salt
conditions (NaCl, 15%, w/w). Here we described the BA wastewater as a redox mediator in the bio-decolorization of azo dye
wastewaters. Decolorization of azo dyes was carried out experimentally using the salt-tolerant bacteria under the BA wastewater
and high-salt conditions. The BA wastewater used as a redox mediator was able to increase the decolorization rate of wastewater
containing azo dyes. The effects of various operating conditions such as dissolved oxygen, temperature, and pH on microbial
decolorization were investigated experimentally. At the same time, BA was tested to assess the effects on the change of the
Oxidation–Reduction Potential (ORP) values during the decolorization processes. The experiments explored a great improvement
of the redox mediator application and the new bio-treatment concept. 相似文献
992.
Anaerobic bacteria have been used to produce 2,4-dihydroxylamino-nitrotoluene (2,4DHANT), a reductive metabolite of 2,4,6-trinitrotoluene
(TNT). Here, an aerobic TNT biodegrader Pseudomonas sp. strain TM15 produced 2,4DHANT as evidenced by the molecular ion with m/z of 199 identified from LC-TOFMS analyses. TNT
biodegradation with a high cell concentration (109 cells/ml) led to a significant accumulation of 2,4DHANT in the culture medium, as well as hydroxylamino-dinitrotoluenes (HADNTs),
although these products were not accumulated when a low cell concentration was used; also, the accumulation of diamino-nitrotoluene
and of an unidentified metabolite were observed in the culture medium with the high cell concentration (1010 cells/ml). 2,4DHANT overproduction was a function of the aeration speed since cultures with low aeration speeds (30 rpm)
had a 19-fold higher DHANT productivity than those aerated with high speeds (180 rpm); this indicates that molecular oxygen
was related to the formation of 2,4DHANT. The quantification of dissolved oxygen (DO) in the media demonstrated that the productivity
of 2,4DHANT was increased at low DO values. Moreover, supplying oxygen to the culture media produced a remarkable decrease
of 2,4DHANT accumulation; these results clearly indicate that high 2,4DHANT production was a consequence of the oxygen deficit
in the culture medium. This finding is useful for understanding the TNT biodegradation (bioremediation technology) in an anoxic
environment.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
993.
Characterization of lactic acid bacteria isolated from sourdoughs for Cornetto, a traditional bread produced in Basilicata (Southern Italy) 总被引:1,自引:1,他引:0
Teresa Zotta Paolo Piraino Eugenio Parente Giovanni Salzano Annamaria Ricciardi 《World journal of microbiology & biotechnology》2008,24(9):1785-1795
A total of 41 strains of lactic acid bacteria (LAB) isolated from durum wheat sourdoughs used to produce Cornetto di Matera bread, were identified by SDS-PAGE of whole cell proteins (WCP) and screened for acid production ability, antimicrobial
activity and exopolysaccharide (EPS) production. The isolates were identified as Lactobacillus plantarum (49%), Leuconostoc mesenteroides (17%), Lactobacillus curvatus (15%), Lactobacillus paraplantarum (12%), Weissella cibaria (5%) and Lactobacillus pentosus (2%). Several strains of Lb. plantarum and Leuc. mesenteroides showed a high acid production ability. The antagonistic activity was tested using an agar-spot deferred antagonism assay
against a set of five indicators. The species had different profiles of inhibition. Lb. plantarum had the largest spectrum of inhibition, while no isolates of W. cibaria and Leuc. mesenteroides showed antimicrobial activity. No strains had antimicrobial activity against Bacillus cereus. The inhibitory activity of five strains was confirmed to be sensitive to proteolytic enzymes and thus potentially due to
bacteriocin production. All Leuc. mesenteroides and W. cibaria strains produced EPS from sucrose. Some Lb. plantarum and Lb. paraplantarum strains produced EPS from different sugars in solid media. EPS production in liquid media was different within the species,
with the highest production in liquid media containing glucose and maltose. A defined strain starter culture (W. cibaria DBPZ1006, Lb. plantarum DBPZ1015 and S. cerevisiae MTG10) was selected on the basis of technological properties and tested in model sourdough fermentations. 相似文献
994.
Sulfate reducing bacteria (SRB) are commonly used in environmental bioprocesses for the treatment of acid mine drainage and sulfate wastewaters. Biogenic H(2)S is also a potential source of H(2) fuel with the recent development of H(2)S splitting technologies. In this study, a sulfate reducing packed bed bioreactor (PBR) capable of rapidly achieving high volumetric productivities was developed using a novel method of rational inoculum design and the selection of improved biomass carrier materials. An inoculum with initial composition of approximately 95% Desulfovibrio desulfuricans (ATCC 7757) and 5% SRB consortium was designed based on the pure strain's superior immobilization potential and the SRB consortium's superior kinetics. Diatomaceous earth (DE) pellets, porous glass beads, polyurethane foam and bone char were evaluated as potential biomass carrier materials. The DE pellets immobilized the most biomass and were employed in two packed bed bioreactor fermentations. Using the designed inoculum and DE pellets, a packed bed bioreactor achieved a volumetric productivity of 493 mol H(2)S m(-3) day(-1) (based on a 308 mL working volume) with a dissolved sulfide concentration of 9.9 mM. This occurred after 8.3 days of operation and represents a tenfold reduction in the start-up period compared to other sulfate reducing PBRs described in the literature. 相似文献
995.
Proton transport inside the biofilm limits electrical current generation by anode-respiring bacteria
Anode-respiring bacteria (ARB) in a biofilm anode carry out an oxidation half-reaction of organic matter, producing an electrical current from renewable biomass, including wastes. At the same time, ARB produce protons, usually one proton for every electron. Our study shows how current density generated by an acclimated ARB biofilm was limited by proton transport out of the biofilm. We determined that, at high current densities, protons were mainly transported out of the biofilm by protonating the conjugate base of the buffer system; the maximum current generation was directly related to the transport of the buffer, mainly by diffusion, into and out of the biofilm. With non-limiting acetate concentrations, the current density increased with higher buffer concentrations, going from 2.21 +/- 0.02 A m(-2) with 12.5-mM phosphate buffer medium to 9.3 +/- 0.4 A m(-2) using a 100-mM phosphate buffer at a constant anode potential of E(anode) = -0.35 V versus Ag/AgCl. Increasing the concentration of sodium chloride in the medium (0-100 mM) increased current density by only 15%, indicating that ion migration was not as important as diffusion of phosphate inside the biofilm. The current density also varied strongly with medium pH as a result of the buffer speciation: The current density was 10.0 +/- 0.8 A m(-2) at pH 8, and the pH giving one-half the maximum rate was 6.5. A j-V curve analysis using 100 mM phosphate buffer showed a maximum current density of 11.5 +/- 0.9 A m(-2) and half-saturation potential of -0.414 V versus Ag/AgCl, a value that deviated only slightly from the standard acetate potential, resulting in small anode-potential losses. We discuss the implications of the proton-transport limitation in the field of microbial fuel cells and microbial electrolytic cells. 相似文献
996.
Bioremediation of contaminated soils and aquifers is subject to spatial and temporal temperature changes that can alter the kinetics of key microbial processes. This study quantifies temperature effects on the kinetics of an ethanol-fed sulfate-reducing mixed culture derived from a uranium-contaminated aquifer subject to seasonal temperature fluctuations. The mixed culture contains Desulfovibrio sp. and a Clostridia-like organism. Rates of growth, ethanol utilization, decay, and uranium reduction decreased with decreasing temperature. No significant uranium reduction was observed at 10 degrees C. While both Monod saturation kinetics and pseudo second-order kinetics adequately described the rates of growth and utilization of electron donor (ethanol), model parameters for the pseudo second-order expression had smaller uncertainties. Uranium reduction kinetics were best described by pseudo second-order kinetics modified to include a term for inactivation/death of cells. 相似文献
997.
Park YJ Ko JJ Yun SL Lee EY Kim SJ Kang SW Lee BC Kim SK 《Bioresource technology》2008,99(16):7458-7463
In this study, the potential for the application of the bioaugmentation to Cd and Zn contaminated sediment was investigated. A batch experiment was performed in the lake sediments augmented with Ralstonia sp. HM-1. The degradation capacity of 18.7 mg-DOC/l/day in the treatment group was bigger than that of the blank group (4.4 mg-DOC/l/day). It can be regarded as the result of the reduction of the metal concentration in the liquid phase due to adsorption into the sediments, with the increased alkalinity resulting from the reduction of sulfate by sulfate reducing bacteria (SRB). The removal efficiency of cadmium and zinc in the treatment group was both 99.7% after 35 days. Restrain of elution to water phase from sediment in the Ralstonia sp. HM-1 added treatment group was also shown. In particular, the observed reduction of the exchangeable fraction and an increase in the bound to organics or sulfide fraction in the treatment group indicate its role in the prevention of metal elution from the sediment. Therefore, for bioremediation and restrain of elution from the sediment polluted by metal, Ralstonia sp. augmentation with indigenous microorganism including SRB, sediment stabilization and restrain of elution to surface water is recommended. 相似文献
998.
999.
烟草内生细菌防治烟草黑胫病及促生作用研究 总被引:12,自引:0,他引:12
筛选烟草内生细菌防治烟草黑胫病,获得了对烟草黑胫病有很好防效的内生细菌118、57和93等菌株.在温室控病实验中它们的防效分别可达69.23%、61.53%和65.38%.118菌株对烟草疫霉(Phytophthora parasitica var.nicotianae)菌丝生长有明显的拮抗作用.118菌株具有较广的抗菌谱,且对烟草有促生效果,烟草的鲜重增产率为13.10%. 相似文献
1000.