Treatment of a textile effluent from dyeing with cochineal extracts using Trametes versicolor fungus.

Trametes versicolor (Tv) fungus can degrade synthetic dyes that contain azo groups, anthraquinone, triphenylmethane polymers, and heterocyclic groups. However, no references have been found related to the degradation of natural dyes, such as the carminic acid that is contained in the cochineal extract. Experiments to determine the decolorization of the effluent used in the cotton dyeing process with cochineal extract by means of Tv fungus were done. Treatments to determine decolorization in the presence or absence of Kirk's medium, glucose, and fungus, with an addition of 50% (v v-1) of nonsterilized effluent were performed. Physicochemical characterization was performed at the start and end of the treatment. Degradation kinetics were determined. A direct relationship was found between the dry weight of fungi, pH, and the decolorization system, with higher decolorization at lower pH levels (pH ~4.3). High decolorization (81% ± 0.09; 88% ± 0.17; and 99% ± 0.04) for three of the eight treatments (Kirk's medium without glucose, Kirk's medium with glucose, and without medium with glucose, respectively) was found. Toxicity tests determined an increase in the initial effluent toxicity (7.33 TU) compared with the final treatment (47.73 TU) in a period of 11 days. For this system, a degradation sequence of the carminic acid structure present in the effluent by the Tv fungus is suggested, in which it is seen that metabolites still containing aromatic structures are generated.

Application of 2III7-3 fractional factorial experimental design to enhance enzymatic activities of Pleurotus ostreatus with high concentrations of polychlorinated biphenyls.

A 2(III)(7-3) fractional factorial experimental design was used to establish 16 culture media, with and without PCBs to enhance the activities of laccase (Lac), manganese peroxidase (MnP), and versatile peroxidase (VP) produced by the white rot fungus Pleurotus ostreatus. The culture was added to 10,000 mg L(-1) of transformer oil, containing 71% of the identified Arochlor 1242. The culture conditions were established with eight variables at two values (levels); pH (4 and 6), agitation (100 and 200 rpm), CuSO(4) (150 and 250 mg L(-1)), MnSO(4) (50 and 200 mg L(-1)), Tween 80 (13 and 3500 mg L(-1)), wheat straw (0 and 2.5 g L(-1)), sugarcane bagasse (0 and 2.5 g L(-1)),and Arochlor 1242 (0 and 7100 mg L(-1)) at 4, 8, 12, 16 and 20 days old culture. Laccase activity was enhanced at a high value of pH and low value of agitation (P<0.001) and correlated positively (R(2)= 0.9; α=0.05) with the removal of polychlorinated biphenyls (PCBs). VP activity was enhanced 27-fold with PCBs, Tween 80 and pH. The MnP activity was increased 1.2-fold with PCBs. The fractional factorial experimental design methodology allowed us to determine the P. ostreatus culture media conditions to enhance Lac and VP activities for efficient removal of Arochlor 1242 (one of the most recalcitrant organochloride pollutants). The factors that shown the greatest effect on Lac activity were: pH, agitation and high concentrations of Arochlor 1242.

Enhanced anaerobic biodegradation of BTEX-ethanol mixtures in aquifer columns amended with sulfate, chelated ferric iron or nitrate.

Flow-through aquifer columns were used to investigate the feasibility of adding sulfate, EDTA-Fe(III) or nitrate to enhance the biodegradation of BTEX and ethanol mixtures. The rapid biodegradation of ethanol near the inlet depleted the influent dissolved oxygen (8 mg l(-1)), stimulated methanogenesis, and decreased BTEX biodegradation efficiencies from > 99% in the absence of ethanol to an average of 32% for benzene, 49% for toluene, 77% for ethylbenzene, and about 30% for xylenes. The addition of sulfate, EDTA-Fe(III) or nitrate suppressed methanogenesis and significantly increased BTEX biodegradation efficiencies. Nevertheless, occasional clogging was experienced by the column augmented with EDTA-Fe(III) due to iron precipitation. Enhanced benzene biodegradation (> 70% in all biostimulated columns) is noteworthy because benzene is often recalcitrant under anaerobic conditions. Influent dissolved oxygen apparently played a critical role because no significant benzene biotransformation was observed after oxygen was purged out of the influent media. The addition of anaerobic electron acceptors could enhance BTEX biodegradation not only by facilitating their anaerobic biodegradation but also by accelerating the mineralization of ethanol or other substrates that are labile under anaerobic conditions. This would alleviate the biochemical oxygen demand (BOD) and increase the likelihood that entraining oxygen would be used for the biotransformation of residual BTEX.

Effect of ethanol and methyl-tert-butyl ether on monoaromatic hydrocarbon biodegradation: response variability for different aquifer materials under various electron-accepting conditions.

Aquifer microcosms were used to determine how ethanol and methyl-tert-butyl ether (MtBE) affect monoaromatic hydrocarbon degradation under different electron-accepting conditions commonly found in contaminated sites experiencing natural attenuation. Response variability was investigated by using aquifer material from four sites with different exposure history. The lag phase prior to benzene, toluene, ethylbenzene, and xylenes (BTEX) and ethanol degradation was typically shorter in microcosms with previously contaminated aquifer material, although previous exposure did not always result in high degradation activity. Toluene was degraded in all aquifer materials and generally under a broader range of electron-accepting conditions compared to benzene, which was degraded only under aerobic conditions. The MtBE was not degraded within 100 d under any condition, and it did not affect BTEX or ethanol degradation patterns. Ethanol was often degraded before BTEX compounds and had a variable effect on BTEX degradation as a function of electron-accepting conditions and aquifer material source. An occasional enhancement of toluene degradation by ethanol occurred in denitrifying microcosms with unlimited nitrate; this may be attributable to the fortuitous growth of toluene-degrading bacteria during ethanol degradation. Nevertheless, experiments with flow-through aquifer columns showed that this beneficial effect could be eclipsed by an ethanol-driven depletion of electron acceptors, which significantly inhibited BTEX degradation and is probably the most important mechanism by which ethanol could hinder BTEX natural attenuation. A decrease in natural attenuation could increase the likelihood that BTEX compounds reach a receptor as well as the potential duration of exposure.