In vivo decolourization of the polymeric dye poly R‐478 by corncob cultures of Phanerochaete chrysosporium

In this paper, the in vivo decolourization of the polymeric dye Poly R‐478 by semi‐solid‐state cultures of Phanerochaete chrysosporium BKM‐F‐1767 (ATCC 24725) was investigated, employing corncob as a support. In order to stimulate the ligninolytic system of the fungus, the cultures were supplemented with veratryl alcohol (2 mM) or manganese (IV) oxide (1 g/l). Maximum manganese‐dependent peroxidase (MnP) and lignin peroxidase (LiP) activities of around 2,000 U/l and 400 U/l were attained by the former, whereas the activities reached by the latter were of about 1,500 U/l and 200 U/l, respectively. Furthermore, laccase activity (around 150 U/l) was only detected in manganese (IV) oxide supplemented cultures. The polymeric dye Poly R‐478 (0.02 w/v) was added to three‐day‐old cultures. A percentage of biological decolourization of about 85% was achieved using cultures supplemented with veratryl alcohol, whereas MnO₂ cultures showed a rather lower percentage of around 58% after nine days of dye incubation. Moreover, a correlation between MnP activity and Poly R‐478 decolourization could be observed, indicating that this enzyme is mainly responsible for dye degradation. In the present work, the in vivo decolourizing capability of the ligninolytic complex secreted by P. chrysosporium was investigated under the above‐mentioned cultivation conditions, employing a model compound, such as the polymeric dye Poly R‐478.     

Decolorization of anthraquinone dye by Shewanella decolorationis S12

A new species of genus Shewanella, Shewanella decolorationis S12, from activated sludge of a textile-printing wastewater treatment plant, can decolorize Reactive Brilliant Blue K-GR, one kind of anthraquinone dye, with flocculation first. Although S. decolorationis displayed good growth in an aerobic condition, color removal was the best in an anaerobic condition. For color removal, the most suitable pH values and temperatures were pH 6.0–8.0 and 30–37°C under anaerobic culture. More than 99% of Reactive Brilliant Blue K-GR was removed in color within 15 h at a dye concentration of 50 mg/l. Lactate was the suitable carbon source for the dye decolorization. A metal compound, HgCl₂, had the inhibitory effect on decolorization of Reactive Brilliant Blue K-GR, but a nearly complete decolorization also could be observed at a HgCl₂ concentration of 10 mg/l. The enzyme activities, which mediate the tested dye decolorization, were not significantly affected by preadaptation of the bacterium to the dye.     

Degradation of Crystal violet by Nocardia corallina

Crystal Violet (BV3), a typical triphenylmethane dye, was degraded by growing cells of Nocardia corallina IAM 12121, although their growth was inhibited at the initial stage of incubation. The dye was degraded at a low concentration, below 5 mol dm^–3. The growth of the cells was completely inhibited at a dye concentration of 7 mol dm^–3. A degradation product of BV3 was identified as 4,4-bis(dimethylamino) benzophenone (Michler's ketone; MK) by gas chromatography-mass spectrometry. The product was obtained in a reasonable yield since it was not further metabolized by N. corallina IAM 12121. Correspondence to: C. Yatome     

Effect of nutritional conditions on dye removal from textile effluent by <Emphasis Type="Italic">Aspergillus lentulus</Emphasis>

The nutritional conditions supporting growth and maximum dye removal by Aspergillus lentulus have been investigated. Initially a composite media containing yeast extract, glucose and mineral components was used and the effect of various components on dye removal was studied. For maximum dye removal (≈100%), ≥0.5% (w/v) glucose and ≥0.25% (w/v) yeast extract were essential. While glucose played an important role in pellet formation, which in turn was important for dye removal, yeast extract contributed towards higher biomass production. Mineral components (except NH₄NO₃) did not affect dye removal significantly. Next the alternate sources of carbon (molasses, jaggery, starch and sodium acetate) and nitrogen (peptone, urea, ammonium nitrate, sodium nitrate and ammonium chloride) were tested. Among carbon sources, all the sources produced almost complete dye removal in 48 h (more than 97% in 24 h), except sodium acetate (64% in 48 h). All the tested nitrogen sources resulted in >90% dye removal in 48 h. Yeast extract and peptone gave best results with high dye removal rate (9.8 and 8.1 mg/l/h, respectively). However, among the low cost alternates, urea and NH₄Cl came out to be suitable sources due to the high uptake capacity of the biomass produced coupled with high dye removal rate in case of NH₄Cl. Therefore, a combination of urea and NH₄Cl was tested, which produced complete dye removal with a high dye removal rate (10 mg/l/h). Finally the modified composite media containing urea and NH₄Cl as nitrogen sources and glucose as carbon source was utilized for effluent treatment. Results indicated that performance of modified composite media was at par with composite media for supporting growth of A. lentulus and dye removal from the textile effluent.     

A breakthrough column study for removal of malachite green using coco-peat

Abstract

A continuous adsorption study in a fixed bed column using coco-peat (CP) as an adsorbent was carried out for the removal of toxic malachite green (MG) from contaminated water. Fixed bed column studies were carried out to check field application viability. Various parameters like particle size, pH, concentration, dose and interference were exercised to optimize dye removal. Data obtained from breakthrough column studies were evaluated using Thomas and BDST model. Thomas rate constants K_t (0.22?ml min^?1 mg^?1) and adsorption capacity q_o (181.04?mg g^?1) were estimated and found to favor efficiency of CP. Thomas model was tested with several parameters like flow rate, concentration, and bed depth. Upon increase in input dye concentration, flow rate and bed height, adsorption coefficients increased. According to BDST model, maximum dye uptake of 468.26?mg/l was obtained with an input dye concentration of 5?mg/l. HYBRID and MPSD error functions were tested and found that Thomas model fits best. Dilute hydrochloric acid was found best for desorption. Real wastewater from textile industry was analyzed and confirmed the prospect of large-scale industrial application. In conclusion, coco-peat can be used as a promising bio-sorbent in column bed for scavenging of MG from contaminated water.     

Biosorption of an Azo Dye by <Emphasis Type="Italic">Aspergillus niger</Emphasis> and <Emphasis Type="Italic">Trichoderma</Emphasis> sp. Fungal Biomasses

Biosorption is an eco-friendly and cost-effective method for treating the dye house effluents. Aspergillus niger and Trichoderma sp. were cultivated in bulk and biomasses used as biosorbents for the biosorption of an azo dye Orange G. Batch biosorption studies were performed for the removal of Orange G from aqueous solutions by varying the parameters like initial aqueous phase pH, biomass dosage, and initial dye concentration. It was found that the maximum biosorption was occurred at pH 2. Experimental data were analyzed by model equations such as Langmuir and Freundlich isotherms, and it was found that both the isotherm models best fitted the adsorption data. The monolayer saturation capacity was 0.48 mg/g for Aspergillus niger and 0.45 mg/g for Trichoderma sp. biomasses. The biosorption kinetic data were tested with pseudo first-order and pseudo second-order rate equations, and it was found that the pseudo second-order model fitted the data well for both the biomasses. The rate constant for the pseudo second-order model was found to be 10–0.8 (g/mg min⁻¹) for Aspergillus niger and 8–0.4 (g/mg min⁻¹) for Trichoderma sp. by varying the initial dye concentrations from 5 to 25 mg/l. It was found that the biomass obtained from Aspergillus niger was a better biosorbent for the biosorption of Orange G dye when compared to Trichoderma sp.     

Biodegradation of Green HE4B: Co-substrate effect,biotransformation enzymes and metabolite toxicity analysis

A high exhaust reactive dye, Green HE4B (GHE4B) was 98% degraded in nutrient medium by Pseudomonas desmolyticum NCIM 2112 (pd2112) within 72 h at static condition. Decolorization time in synthetic 10 g/l molasses. Addition of 5 g/l peptone to NaCl medium had reduced decolorization time from 108 to 72 h. Beef extract do not contribute more to the inducing effect of peptone, however it is a good co-substrate in sucrose or urea containing NaCl medium. Intracellular lignin peroxidase (Lip), laccase and tyrosinase activities were induced by 150, 355 and 212%, respectively till maximum dye removal took place. Aminopyrine N-demethylase (AND) and dichlorophenol indophenol reductase (DCIP-reductase) activities in pd2112 were induced by 130 and 20%, respectively at 72 h of incubation during GHE4B decolorization. By high performance liquid chromatography (HPLC) analysis, 4-hydroxybenzene sulfonic acid and 4-amino, 6-hydroxynaphthalene 2-sulfonic acids were identified as metabolites formed during 24–72 h incubation. Fourier transform infrared spectroscopy (FTIR) analysis supports the formation of these aromatic amines. pd2112, aerobically degraded GHE4B metabolites (formed at static condition) showing stationary phase of 6 days. There was no germination inhibition of Sorghum bicolor and Triticum aestivum by GHE4B metabolites at 3,000 ppm concentration however untreated dye showed germination inhibition at the same concentration. GHE4B metabolites did not show any microbial toxicity at 10,000 ppm concentration.     

Comparative study on methyl orange removal by growing cells and washed cell suspensions of <Emphasis Type="Italic">Lactobacillus casei</Emphasis> TISTR 1500

Lactobacillus casei TISTR 1500 possesses cytoplasmic azoreductase, and converts methyl orange to N,N-dimethyl-p-phenylenediamine and 4-aminobenzenesulfonic acid. In culture growth, the strain completely degraded methyl orange at 200 mg/l, even though the pH value was lower than 4. The decolorization was inhibited in the growing culture with 800 mg of the dye/l after incubation for 12 h. The percentage of decolorization and specific decolorization rate with 400 and 800 mg/l were 66 and 15%, and 14.2, and 8.7 mg/gCell/h, respectively. Additionally, a growing culture is more tolerant to a high initial dye concentration than when using washed cell suspensions supplied with only sucrose. Moreover, incubation of a low cell density in 600 μM of Na⁺ and 20 mM of sucrose increased the specific decolorization rate from 2.34 mg/gCell/h (without Na⁺) to 4.32 mg/gCell/h. However, Na⁺ had no effect on the enhancement of azoreductase activity in the reaction mixture.     

Utilisation of lignocellulosic wastes for lignin peroxidase production by semi-solid-state cultures of Phanerochaete chrysosporium

In the present work, the production of ligninolytic enzymes by semi-solid-statecultures of Phanerochaete chrysosporium BKM-F-1767 (ATCC 24725),employing different lignocellulosic wastes as support, was investigated. Thewaste materials employed were grape seeds, wheat straw and wood shavings.Maximum lignin peroxidase activities of 1620 ± 123 U/l, 364 ± 35 U/l and 571 ± 42 U/l were attained, respectively. Nevertheless, lowmanganese-dependent peroxidase activities were found, being insignificantin the grape seed cultures. Moreover, the in vivo decolourisation of a model dye compound, the polymeric dye Poly R-478 (polyvinylamine sulfonateanthrapyridone), by the above-mentioned cultures was monitored to assessthe degrading capability of the extracellular liquid secreted by such cultures.The percentage of biological decolourisation attained by grape seed and woodshaving cultures was around 74% and 63%, respectively, whereas it was ratherlow (40%) in the wheat straw ones.     

Decolourization and Detoxification of Methyl Red by Aerobic Bacteria from A Wastewater Treatment Plant

Bacterial cultures from a wastewater treatment plant degraded a toxic azo dye (methyl red) by decolourization. Complete decolourization using a mixed-culture was achieved at pH 6, 30 °C within 6 h at 5 mg/l methyl red concentration, and 16 h at 20—30 mg/l. Four bacterial species were isolated that were capable of growth on methyl red as the sole carbon source, and two were identified, namely Vibrio logei and Pseudomonas nitroreducens. The Vibrio species showed the highest methyl red degradation activity at the optimum conditions of pH 6--7, and 30—35 °C. Analysis by NMR showed that previously reported degradation products 2-aminobenzoic acid and N,N-dimethyl-1,4-phenylenediamine were not observed. The decolourized dye was not toxic to a monkey kidney cell line (COS-7) at a concentration of 250 μM. This revised version was published online in July 2006 with corrections to the Cover Date.     

New effects and applications of thioflavins

The thiazol dye Thioflavin T (ThT), which is used to stain amyloid fibrils, was found to have strong inhibitory effects on both growth and conidiation of the deuteromycete Trichoderma viride at concentrations between 10–100 μg/ml (ca. 30–300 μmol/l). Thioflavin S (ThS), also known to stain amyloid fibrils, had no significant effect at these concentrations. Both stains yielded a fluorescence response, but their distributions were different. ThT was non-homogenously distributed throughout the cytoplasm, whereas ThS fluorescence was strongly bound to septal regions. The effect of ThT was studied on several model microorganisms. It exerted a strong inhibitory effect on Staphylococcus aureus (Gram-positive bacterium) (MIC=10 μmol/l), but the effect on Escherichia coli (Gram-negative bacterium) was one order of magnitude less pronounced. The effect on Candida albicans was also very strong (MIC=50 μmol/l). The dermatophytic fungus Microsporum gypseum and deuteromycete Alternaria alternata were less affected by ThT (MIC=250 μmol/l and >500 μmol/l, respectively). These results show that ThT could be a useful inhibitor of selected microorganisms, whereas ThS could be a useful agent for monitoring formation and maintenance of intrahyphal septa without inhibiting the growth of the microorganism.     

Food and water resources used by the Madagascan hissing-cockroach mite,Gromphadorholaelaps schaeferi

We determined the food source and water balance properties of the hissing-cockroach mite, Gromphadorholaelaps schaeferi. The food source for mites was identified using Evans blue dye by direct injection into a fasting host cockroach, Gromphadorhina portentosa, or by incorporation into cockroach food. No coloration was observed in mites on dye-injected cockroaches, but coloration was present in mites when only the food for the cockroaches had been stained. Thus, the mites are scavengers of cockroach food, and are not parasitic as previously thought. Our results demonstrate that the mites can absorb water from the air anywhere between 0.84 and 0.93 a _v (%RH/100), and wax-block experiments revealed that the mouth is the site of uptake. The mites are normally clumped together on the host, typically in between the cockroach's legs and around the spiracles. Water loss rates for mites in groups (0.16% h^-1) were far lower than for isolated mites (0.30% h^-1), suggesting a group effect with regard to water balance. Above the transition temperature of 30°C rate of water loss was rapid. The sites occupied by mites on the cockroach's body seem to be highly specific for feeding and absorption of water vapour.     

Bio-remediation of colored industrial wastewaters by the white-rot fungi Phanerochaete chrysosporium and Pleurotus ostreatus and their enzymes

The effect of Phanerochaete chrysosporium and Pleurotus ostreatus whole cells and their ligninolytic enzymes on models of colored industrial wastewaters was evaluated. Models of acid, direct and reactive dye wastewaters from textile industry have been defined on the basis of discharged amounts, economic relevance and representativeness of chemical structures of the contained dyes. Phanerochaete chrysosporium provided an effective decolourization of direct dye wastewater model, reaching about 45% decolourization in only 1 day of treatment, and about 90% decolourization within 7 days, whilst P. ostreatus was able to decolorize and detoxify acid dye wastewater model providing 40% decolourization in only 1 day, and 60% in 7 days. P. ostreatus growth conditions that induce laccase production (up to 130,000 U/l) were identified, and extra-cellular enzyme mixtures, with known laccase isoenzyme composition, were produced and used in wastewater models decolourization. The mixtures decolorized and detoxified the acid dye wastewater model, suggesting laccases as the main agents of wastewater decolourization by P. ostreatus. A laccase mixture was immobilized by entrapment in Cu-alginate beads, and the immobilized enzymes were shown to be effective in batch decolourization, even after 15 stepwise additions of dye for a total exposure of about 1 month.     

Enhanced decolorization of sulfonated azo dye methyl orange by single and mixed bacterial strains AK1, AK2 and VKY1

Abstract

Methyl orange, a sulfonated azo dye having various industrial applications was decolorized by three bacteria Bacillus sp. strain AK1, Lysinibacillus sp. strain AK2 and Kerstersia sp. strain VKY1. The effect of various factors such as dye concentration, pH, temperature and NaCl concentration on decolorization was investigated. At 200?mg/L methyl orange concentration, the strains AK1, AK2 and VKY1 exhibited maximum decolorizing potential of 93, 95 and 96%, respectively, at temperature 35?°C and pH 7.0 within 18?h of incubation. These strains decolorized the dye over a wide range of pH (5–10), temperature (15–55?°C), and NaCl concentration (5–20?g/L). Further, these strains decolorize up to 800?mg/L concentrations of methyl orange within 24?h. The dye decolorization efficiency was further increased by using different consortia of these three strains which could decolorize the dye completely within 12?h of incubation. The cell-free extracts of the strains AK1, AK2 and VKY1 grown on methyl orange exhibited the azoreductase activity of 0.4794, 1.56 and 1.01?µM/min/mg protein, respectively. HPLC and FTIR analysis of the dye decolorized sample indicated the formation of 4-aminobenzenesulfonic acid and N,N-dimethyl-p-phenylenediamine as breakdown products of azo bond. The high decolorization potential of these bacterial strains individually and in consortia has potential application in remediation of dye effluent.     

Biodegradation of acid blue-15, a textile dye,by an up-flow immobilized cell bioreactor

Acid blue-15, a complex and resonance-stabilized triphenylmethane (TPM) textile dye, resistant to transformation, was decolorized/degraded in an up-flow immobilized cell bioreactor. A consortium comprised of isolates belonging to Bacillus sp., Alcaligenes sp. and Aeromonas sp. formed a multispecies biofilm on refractory brick pieces used as support material. The TPM dye was degraded to simple metabolic intermediates in the bioreactor with 94% decolorization at a flow rate of 4 ml h^–1.     

High production of laccase B from <Emphasis Type="Italic">Trametes</Emphasis> sp. in <Emphasis Type="Italic">Pichia pastoris</Emphasis>

The coding sequence of a laccase isozyme from Trametes sp. AH28-2 was cloned in pPIC9K vector and heterologously overexpressed in the yeast Pichia pastoris strain GS115. In the minimal medium containing 0.3 mM CuSO₄ and 0.6% alanine, the maximum yield of the recombinant laccase rLacB reached 32,000 U/l (1,012 U/mg), slightly higher than that of the native enzyme nLacB (∼30,000 U/l, 1,356 U/mg). The enzymatic properties of rLacB were different from those of nLacB as well. Regardless of the inferior thermal stability, rLacB had much better stability at both neutral and basic pH range compared to nLacB. In addition, the dye decolorization potential of rLacB was similar to that of nLacB.     

Dye decolorisation by laccase entrapped in copper alginate

A novel immobilisation system was developed for dye decolorisation using laccase produced by Ganoderma sp. KU-Alk4. The enzyme showed high efficiency in dye decolorisation when entrapped in Cu–Al and Cu-alginate beads. The former gave the highest activity but the enzyme activity survived longer in the latter. An experimental design of two 3 × 3 Latin Square experiments was applied to evaluate the effects of three different alginate compositions (low, intermediate and high mannuronate), concentration of alginate, (1.5, 3.0 and 4.5% w/v) and concentration of cross-linking agent, CuSO₄ (0.075, 0.15 and 0.225 M) on the decolorisation of indigo carmine dye and residual laccase activity in beads. The most significant factor for residual activity was the concentration of the cross-linking agent (P < 0.05) followed by alginate composition (P < 0.1). Increasing the alginate concentration resulted in only small increase in the dye decolorisation. However, higher laccase activity remained in 3.0% w/v alginate beads. Maximal dye decolorisation was achieved when 3.6% w/v low mannuronate alginate and 0.15 M CuSO₄ was used. Optimal conditions were confirmed in an extended experimental run. Results are presented from 9 successive batch runs over 12 days, reaching 96% removal of the dye (216 mg/l).     

A modified visual loop-mediated isothermal amplification method for diagnosis and differentiation of main pathogens from Mycobacterium tuberculosis complex

This study was aimed to rapidly identify and differentiate two main pathogens of the Mycobacterium tuberculosis complex: Mycobacterium tuberculosis subsp. tuberculosis and Mycobacterium bovis by a modified loop-mediated isothermal amplification (LAMP) assay. The reaction results could be evaluated by naked eye with two optimized closed tube detection methods as follows: adding the modified fluorescence dye in advance into the reaction mix so as to observe the color changes or putting a tinfoil in the tube and adding the SYBR Green I dye on it, then making the dye drop into the bottom of the tube by centrifuge after reaction. The results showed that the two groups of primers used jointly in this assay could successfully identify and differentiate Mycobacterium tuberculosis subsp. tuberculosis and Mycobacterium tuberculosis bovis. Sensitivity test displayed that the modified LAMP assay with the closed tube system could determine the minimal template concentration of 1 copy/μl, which was more sensitive than that of routine PCR. The advantages of this LAMP method for detection of the Mycobacterium tuberculosis complex included high specificity, high sensitivity, simplicity, and superiority in avoidance of aerosol contamination. The modified LAMP assay would provide a potential for clinical diagnosis and therapy of tuberculosis in the developing countries and the resource-limited areas.     

Feasibility of using <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> biomass for the removal of erioglaucine from aqueous solution

The test fungus Trichoderma harzianum was isolated from the Western Ghats area of Tamilnadu, India. The study involves the feasibility of using T.harzianum to remove erioglaucine from an aqueous solution in batch mode. The batch mode experimental parameters such as effect of agitation time and initial dye concentration, adsorbent mass and pH were determined. The results revealed that, the fungal biomass at 1.5 g/50 ml adsorbent mass removed 75.67–88.05% of dye (10–50 mg/l) in 105 min at pH 4.0. The adsorption equilibrium data followed both Langmuir and Freundlich isotherms. From the Langmuir isotherm, the adsorbent had adsorption capacity (Q ₀ ) of 3.09 mg/g. Pseudo first and second order rate kinetic equations were applied to the experimental adsorption data. The results indicate that the adsorbent system followed second order rate kinetics.     

High blood lead level among garage workers in Bangkok, public concern is necessary

Lead is an important toxic metal agent found in many industrial processes in the present day. Lead exposure must be of particular concern because of ongoing exposure to thousands of workers in the industrial plants and recent research indicating that asymptomatic lead exposure can result in chronic toxicity manifestations. Therefore, determination and control lead exposure among the risk workers is very necessary. Like other developing countries, lead pollution becomes an important public health problem of Thailand, especially for the big cities as Bangkok but relatively few of these countries have introduced policies and regulations for significantly combating the problem. We set this pilot study to determine the blood lead levels by anodic stripping volammetry (ASV) method as a marker for lead exposure among the occupational exposed and control subjects. Totally 89 subjects, 20 control subjects and 69 garage workers (52 mechanics and 17 dye sprayers), as the representatives of occupational exposed subjects, were included into this preliminary study. The mean blood lead level in the control group was 0.32±0.07 mol/l. The mean blood lead level in the mechanics group was 0.42±0.13 mol/l. The mean blood lead level in the dye sprayers was 0.58±0.07 mol/l. Significant higher blood lead levels among the mechanics and dye sprayer groups were observed (P<0.05). Based on this study, the considerations for prevention of possibly exposure to lead among the high-risk workers as public health policies was recommended.