Decolorization of molasses wastewater by yeast strain, Issatchenkia orientalis No. SF9-246

Among 2402 strains of yeast isolated from various sources in Thailand, a strain No. SF9-246 identified as Issatchenkia orientalis, showed the highest potential for use in decolorization of molasses wastewater. In a malt extract-glucose-peptone broth (MYGP) culture containing melanoidin pigment (MP) at 30 °C a 60.2% decolorization was obtained within 7 days. The strain appeared to enhance both MP-degradation and MP-adsorption. The strain showed MP, chemical oxygen demand (COD) and biological oxygen demand (BOD₅) removal efficiencies of 91.2%, 80.0% and 77.4%, respectively from anaerobic-treated molasses wastewater solution (T-MWW), collected from an anaerobic pond. The wastewater contained 2.5% glucose, 0.1% NH₄Cl, and 0.1% KH₂PO₄. The pH was adjusted to 5.0 at 30 °C for 7 days batch type culture system. The strain showed almost constant decolorization yield of 75–80% over 7 days in a periodical feeding system of 10% fresh T-MWW with the culture system. The strain provided a constant decolorization yield about 70% during 3 replacement cycles. Gel filtration chromatography showed that larger molecular weight fraction of MP solution was rapidly removed, while the smaller molecular weight fraction remained in the effluent.     

Treatment of molasses wastewater by acetogenic bacteria BP103 in sequencing batch reactor (SBR) system

Acetogenic bacteria BP103 cells could be used as the absorbent for melanoidin pigment (MP) and molasses wastewater (MWW). The maximum MP adsorption yield of this strain observed from the dead (autoclaved) cell. It was two times higher than that with resting cells. However, the MP adsorption yield of the strain was 50-60% decreased by acclimatization with the media containing MP. The deteriorated cells (MP-adsorbed cells) could be recovered by washing with 0.1% SDS, 0.1% Tween 80 and 0.1 mol/L NaOH solutions. Among them, 0.1 mol/L NaOH solution was most suitable according to highest elution ability and no-effect to the MP adsorption capacity (The adsorption yield of deteriorated cell was reduced only 10% after washing three times with 0.1 mol/L NaOH solution). In SBR system, the strain showed very low MP removal yield with both molasses wastewater (MWW) from the anaerobic pond (An-MWW) and stillage from an alcohol factory (U-MWW). However, the MP removal yield was increased by supplementation with carbon sources (glucose). Also, the MP removal efficiency was increased with the increase of supplemented-glucose concentration. The highest COD, BOD(5), TKN and MP removal efficiencies of the SBR system with 10 times-diluted An-MWW solution containing 30 g/L glucose under HRT of seven days were 65.2+/-2.5%, 82.8+/-3.4%, 32.1+/-0.8% and 50.2+/-3.7%, respectively. The large molecular weight fraction of MP in both U-MWW and An-MWW solutions were rapidly removed by acetogenic bacteria BP103, while the small molecular weight fractions of MP still remained in the effluent.     

Decolorization of textile plant effluent by Citrobacter sp. strain KCTC 18061P

Citrobacter sp. strain KCTC 18061P was found to be able to decolorize textile plant effluent containing different types of reactive dyes. Effects of physico-chemical parameters, such as aeration, nitrogen source, glucose and effluent concentrations on the color removal of real dye effluent by this strain were investigated. The observed changes in the visible spectra indicated color removal by the absorption of dye to cells during incubation with the strain. This strain showed higher decolorization ability under aerobic than static culture conditions. With 1% glucose, this strain removed 70% of effluent color within 5 days. Decolorization was not significantly dependent on the nitrogen sources tested. Chemical oxygen demand (COD) and biological oxygen demand (BOD) were decreased in proportion to incubation times, and their removal rates were about 35% and 50%, respectively, at 7 days of culture.     

耐碱的偶氮染料脱色菌筛选及其特性的研究

从浙江某污水处理厂的活性污泥中筛选出若干株在高pH条件下对偶氮染料酸性大红GR有脱色能力的菌株,经脱色验证得到一株具有高效脱色活性的菌株Z1,经鉴定为巴斯德葡萄球菌(Staphylococcus pasteuri),并对此菌株的脱色特性进行了初步研究。结果表明,在厌氧条件下,Z1在pH7~12,40h对50mg/L的酸性大红GR脱色率均可达90%以上。该菌株对染料有较强的耐受力,在酸性大红GR浓度为300mg/L时,48h的脱色率仍可达93%。此外,该菌株能够对多种偶氮染料脱色,具有较好的脱色广谱性,有望应用于处理工业废水中的偶氮染料。     

Decolorization of synthetic melanoidins-containing wastewater by a bacterial consortium

The presence of melanoidins in molasses wastewater leads to water pollution both due to its dark brown color and its COD contents. In this study, a bacterial consortium isolated from waterfall sediment was tested for its decolorization. The identification of culturable bacteria by 16S rDNA based approach showed that the consortium composed of Klebsiella oxytoca, Serratia mercescens, Citrobacter sp. and unknown bacterium. In the context of academic study, prevention on the difficulties of providing effluent as well as its variations in compositions, several synthetic media prepared with respect to color and COD contents based on analysis of molasses wastewater, i.e., Viandox sauce (13.5% v/v), caramel (30% w/v), beet molasses wastewater (41.5% v/v) and sugarcane molasses wastewater (20% v/v) were used for decolorization using consortium with color removal 9.5, 1.13, 8.02 and 17.5%, respectively, within 2 days. However, Viandox sauce was retained for further study. The effect of initial pH and Viandox concentration on decolorization and growth of bacterial consortium were further determined. The highest decolorization of 18.3% was achieved at pH 4 after 2 day of incubation. Experiments on fresh or used medium and used or fresh bacterial cells, led to conclusion that the limitation of decolorization was due to nutritional deficiency. The effect of aeration on decolorization was also carried out in 2 L laboratory-scale suspended cell bioreactor. The maximum decolorization was 19.3% with aeration at KLa = 2.5836 h⁻¹ (0.1 vvm).     

Optimization for growth of Rhodocyclus gelatinosus in seafood processing effluents

Tuna condensate was a better substrate than shrimp-blanching water or effluent from a frozen-seafood plant for growing Rhodocyclus gelatinosus under anaerobic conditions in the light. One strain out of four examined, R7, gave the highest biomass (4.0 g/l), cell yield (0.32 g cell/g COD), and COD removal (78%) in 1:10 (v/v) diluted tuna condensate. Shrimp-blanching water added to the tuna condensate further increased growth rate, biomass and COD removal. Optimal growth was at pH 7.0 and 3000 Lux light intensity. Acetate, pyruvate, glucose, glutamate, propionate or malate added to the tuna condensate did not increase cell yield, carotenoid or bacteriochlorophyll content or biomass protein. A maximum cell mass of 5.6 g/l (containing 50% protein) and 86% COD removal were obtained after 5 days' incubation under optimal conditions.     

Colour removal of anaerobically treated pulp and paper mill effluent by microorganisms in two steps bioreactor

In the present study sequential anaerobic and aerobic treatment in two steps bioreactor was performed for removal of colour in the pulp and paper mill effluent. In anaerobic treatment, colour (70%), lignin (25%), COD (42%), AOX (15%) and phenol (39%) were reduced in 15 days. The anaerobically treated effluent was separately applied in bioreactor in presence of fungal strain, Paecilomyces sp., and bacterial strain, Microbrevis luteum. Data of study indicated reduction in colour (95%), AOX (67%), lignin (86%), COD (88%) and phenol (63%) by Paecilomyces sp. where as M. luteum showed removal in colour (76%), lignin (69%), COD (75%) AOX (82%) and phenol (93%) by day third when 7 days anaerobically treated effluent was further treated by aerobic microorganisms. Change in pH of the effluent, and increase in biomass of microorganisms substantiated results of the study, which was concomitant to the treatment method.     

模拟精炼糖厂废水云芝脱色及对多糖含量影响*

比较了4株不同云芝PVC0、PVCl、PVC2、PVC3对模拟糖厂废水的总脱色能力及对美拉德反应色素、碱降解色素及焦糖色素的降解能力;比较了添加色素培养对不同云芝菌株生物量及菌丝体多糖(PSK)产量的影响。结果表明,PvCO对模拟废水的脱色率最高,其在废水中培养的菌丝体眺含量虽然较PVC1稍低,但其生物量最大,PSK产量仍然最大。以PVCO为当选菌株进行实验,研究表明浓度75％实际废水的PVCO脱色率为53％,低于对模拟废水的脱色率71％,但两培养的PvCO生物量与PSK产量相当。     

Removal of color from kraft mill wastewaters with cultures of white-rot fungi and with immobilized mycelium of Coriolus versicolor

Screening fifteen strains of white-rot fungi for their ability to decolorize combined bleached kraft effluent showed that Coriolus versicolor in liquid culture removed over 60% of the color of the effluent within six days in the presence of sucrose. Treatment of the same effluent with this fungus, immobilized in beads of calcium alginate gel, resulted in 80% decolorization after three days in the presence of sucrose. Caustic extraction E(1) effluent was also decolorized by the immobilized fungus. Decolorization was achieved more rapidly at pH 5.0 than at pH 7.0. Recycled beads could remove color efficiently and repeatedly in the presence of air but not under anaerobic conditions.     

Decolorization of reactive dyes by mixed cultures isolated from textile effluent under anaerobic conditions

In the present study mixed cultures that could grew in the molasses media were isolated from textile dye effluent and its decolorization activity was studied in a batch system under anaerobic conditions, in order to determine the optimal conditions required for the highest decolorization activity. The optimum pH value for decolorization was determined as 8 for all the dyes tested. In the experiment with pH 8 dye decolorizations by mixed cultures were investigated at about 96.2–1031.3 mg l⁻¹ initial dye concentrations. The highest dye removal rates of mixed cultures were 94.9% for Reactive Red RB, 91.0% for Reactive Black B and 63.6% for Remazol Blue at 953.2, 864.9 and 1031.3 mg l⁻¹ initial dye concentrations respectively within 24 h incubation period. When the Reactive Red RB was used, approximately 82–98% total color removal was obtained at between 96.2 and 953.2 mg l⁻¹ initial dye concentrations after 12 h of incubation at 35 °C. These results show that our enriched mixed cultures have the potential to serve as an excellent biomass for the use in reactive dye removal from wastewaters under anaerobic conditions.     

Decolorization and partial degradation of monoazo dyes in sequential fixed-film anaerobic batch reactor (SFABR)

Decolorization of two monoazo dyes, acid orange 6 (AO6) and acid orange 7 (AO7), were studied in sequential fixed-film anaerobic batch reactor (SFABR) with varying dye concentrations and 500 mg/L glucose as the co-substrate. More than 90% dye decolorization could be achieved, even at 300 mg/L, with both AO6 and AO7 and dye decolorization rates were 168 mg/L/d and 176 mg/L/d, respectively. COD removals with these two monoazo dyes were significantly different, as 75% and 35% decrease were observed with AO6 and AO7, respectively. UV-visible spectral as well as HPLC analysis of SFABR treated effluent showed the accumulation of 4-aminobenzenesulfonate (4-ABS) from AO6 and AO7. Aminoresorcinol (AR) formed from AO6 decolorization could not be detected at the end of SFABR cycle. This along with high COD removal indicated its further degradation. Formation of pink coloration on exposure to air indicated the presence of 1-amino-2-naphthol (AN) in AO7 fed reactor effluent. Thus both 4-ABS and AN were resistant to further degradation under anaerobic conditions. Presence of nitrate did not decrease the observed decolorization at the end of 24h SFABR cycle, although initial rate was decreased. This indicates the suitability of SFABR configuration for the treatment of azo-dye containing wastewaters in the presence of nitrate.     

Decolorization of the textile dyes by newly isolated bacterial strains

Six bacterial strains with the capability of degrading textile dyes were isolated from sludge samples and mud lakes. Aeromonas hydrophila was selected and identified because it exhibited the greatest color removal from various dyes. Although A. hydrophila displayed good growth in aerobic or agitation culture (AGI culture), color removal was the best in anoxic or anaerobic culture (ANA culture). For color removal, the most suitable pH and temperature were pH 5.5-10.0 and 20-35 degrees C under anoxic culture (ANO culture). More than 90% of RED RBN was reduced in color within 8 days at a dye concentration of 3,000 mg l(-1). This strain could also decolorize the media containing a mixture of dyes within 2 days of incubation. Nitrogen sources such as yeast extract or peptone could enhance strongly the decolorization efficiency. In contrast to a nitrogen source, glucose inhibited decolorization activity because the consumed glucose was converted to organic acids that might decrease the pH of the culture medium, thus inhibiting the cell growth and decolorization activity. Decolorization appeared to proceed primarily by biological degradation.     

Decolorization of a recalcitrant organic compound (Melanoidin) by a novel thermotolerant yeast, Candida tropicalis RG-9

ABSTRACT: BACKGROUND: Sugarcane distilleries use molasses for ethanol production and generate large volume ofeffluent containing high biological oxygen demand (BOD) and chemical oxygen demand(COD) along with melanoidin pigment. Melanoidin is a recalcitrant compound that causesseveral toxic effects on living system, therefore, may be treated before disposal. The aim ofthis study was to isolate a potential thermotolerant melanoidin decolorizing yeast fromnatural resources, and optimized different physico-chemical and nutritional parameters. RESULTS: Total 24 yeasts were isolated from the soil samples of near by distillery site, in which isolateY-9 showed maximum decolorization and identified as Candida tropicalis by Microbial TypeCulture Collection (MTCC) Chandigarh, India. The decolorization yield was expressed as thedecrease in the absorbance at 475 nm against initial absorbance at the same wavelength.Uninoculated medium served as control. Yeast showed maximum decolorization (75%) at 45°C using 0.2%, glucose; 0.2%, peptone; 0.05%, MgSO4; 0.01%, KH2PO4; pH-5.5 within 24 hof incubation under static condition. Decolorizing ability of yeast was also confirmed by highperformance liquid chromatography (HPLC) analysis. CONCLUSION: The yeast strain efficiently decolorized melanoidin pigment of distillery effluent at highertemperature than the other earlier reported strains of yeast, therefore, this strain could also beused at industrial level for melanoidin decolorization as it tolerated a wide range oftemperature and pH with very small amount of carbon and nitrogen sources.     

Bioremediation Perspective of Navy Blue Rx–Containing Textile Effluent by Bacterial Isolate

The aim of the present study was to investigate the textile effluent degrading potential of an isolated bacterium, Proteus sp. SUK7. The strain had the capacity to decolorize Navy Blue Rx–containing textile effluent up to 83% within 96 h. The maximum decolorization was observed under static conditions at pH 7.0 and 30°C. Reduction in the chemical oxygen demand (COD) and biological oxygen demand (BOD) of textile effluent was observed after treatment with Proteus sp. SUK7. Induction in the activities of laccase and aminopyrine N-demethylase was observed after decolorization, which indicates involvement of these enzymes in the decolorization process. The presence of various inducers was also found to have a modulatory effect on enzyme activities and the decolorization process. Biodegradation was confirmed using various analytical techniques, such as ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR), gas chromatography–mass spectrometry (GC-MS), and high-performance liquid chromatography (HPLC). A phytotoxicity study was performed to confirm the nontoxic nature of the degradation metabolites.     

Effect of effluent recycling and shock loading on the biodegradation of complex phenolic mixture in hybrid UASB reactors

This study describes the feasibility of anaerobic treatment of synthetic coal wastewater using four identical 13.5L (effective volume) bench scale hybrid up flow anaerobic sludge blanket (HUASB) reactors (R1, R2, R3 and R4) under mesophilic (27+/-5 degrees C) conditions. Synthetic coal wastewater with an average chemical oxygen demand (COD) of 2240 mg/L and phenolics concentration of 752 mg/L was used as substrate. Effluent recirculation was employed at four different effluent to feed recirculation ratios (R/F) of 0.5, 1.0, 1.5 and 2.0 for 100 days to study the effect of recirculation on the performance of the reactors. Phenolics and COD removal was found to improve with increase in effluent recirculation. An effluent to feed recycle ratio of 1.0 resulted in maximum removal of phenolics and COD. Phenolics and COD removal improved from 88% and 92% to 95% each, respectively. The concentration of volatile fatty acids in the effluent was lower than the influent when effluent to feed recirculation was employed. Effect of shock loading on the reactors revealed that phenolics shock load up to 2.5 times increase in the normal input phenolics concentration in the form of continuous shock load for 4days did not affect the reactors performance irreversibly.     

Degradation and decolorization of monosodium glutamate wastewater with <Emphasis Type="Italic">Coriolus versicolor</Emphasis>

Degradation and decolorization of monosodium glutamate wastewater (MSGW) with Coriolus versicolor were firstly carried out. The effects of various operation parameters namely wastewater concentrations, pH, culture time and incidence of sterilization on maximum percentage of degradation and decolorization of wastewater were investigated. Studies of mycelium and enzyme for C. versicolor degradation and decolorization were estimated in this study. Ten percentage of wastewater concentration and pH = 5.0 were found to be the most suitable ones among the other experiments. The highest degradation and decolorization efficiency of wastewater was obtained at the fifth day of cultivation, which was displayed with more than 70% chemical oxygen demand removal, 83% total sugar removal and 55% color removal, respectively. Sterile operation had no remarkable effect on the degradation and decolorization efficiency for C. versicolor. Mycelium and the extra cellular fungal enzyme were both necessary for the degradation and decolorization of MSGW. C. versicolor possesses great potential and economic advantages in MSGW treatment.     

Improvement of the decolorization of azo dye by anaerobic sludge bioaugmented with<Emphasis Type="Italic">Desulfovibrio desulfuricans</Emphasis>

A culture of anaerobic sludge was bioaugmented withDesulfovibrio desulfuricans for the color removal of authentic textile wastewater containing a substantial amount of sulfate, in order to improve the decolorization process. The sulfide produced by sulfate respiration ofD. desulfuricans can chemically reduce azo bonds to produce a colorless metabolite in the form of aromatic amines. In the case where the culture of anaerobic sludge was bioaugmented withD. desulfuricans, the decolorization of C.I. Reactive Black 5 showed an increase of more than 14% after 48 h in comparison with that in the culture of anaerobic sludge alone. In the decolorization of authentic textile wastewater, the color removal (about 69.0%) was improved by the mixed culture of anaerobic sludge andD. desulfuricans, compared with results obtained with only anaerobic sludge as reported in our previous work, suggesting that bioaugmentation byD. desulfuricans can be useful for the decolorization of wastewater that contains complex dye compounds and sulfate.     

Decolorization of a dye industry effluent by <Emphasis Type="Italic">Aspergillus fumigatus</Emphasis> XC6

The strain Aspergillus fumigatus XC6 isolated from mildewing rice straw was evaluated for its ability to decolorize a dye industry effluent. The strain was capable of decolorizing dyes effluent over a pH range 3.0–8.0 with the dyes as sole carbon and nitrogen sources. The optimum pH was 3.0; however, supplemented with either appropriate nitrogen sources (0.2% NH₄Cl or (NH₄)₂SO₄ ) or carbon sources (1.0% sucrose or potato starch), the strain decolorized the effluent completely at the original pH of the dyes effluent. Therefore, A. fumigatus XC6 is an efficient strain for the decolorization of reactive textile dyes effluents, and it might be a practical alternative in dyeing wastewater treatment.     

Effects of pH adjustment by parawood ash and effluent recycle ratio on the performance of anaerobic baffled reactors treating high sulfate wastewater

The objective of this study was to compare the performance of anaerobic baffled reactor (ABR) treating concentrated rubber latex wastewater under different pH adjustment substances and recycling ratios (R). Two ABRs, one received wastewater pretreated with NaOH and the other with ash, were operated at 35 degrees C under identical HRTs from 10 to 1.25d. Results show that both ABRs had highest COD and sulfate removal efficiencies at HRT 10d (averaged 82.71% and 96.16% of ABR-NaOH, and 80.77% and 96.60% of ABR-Ash, respectively), where majority of the influent COD and sulfate were removed by the first compartment of the ABR at all conditions tested. Increasing R (0, 0.3 and 0.5) raised the hydraulic loading on the system and resulted in a drop of organic removal efficiency and methane yield. Translocation of sulfate reducing bacteria and methanogens in the ABRs caused by increased organic loading and effluent recycle is discussed. The results show great potential of parawood ash as a pH adjustment substance for acidic wastewaters.     

Improvement of fermentative decolorization of olive mill wastewater by Lactobacillus paracasei by cheese whey's addition

The effect of the cheese whey's (CW) addition on the fermentative decolorization of olive mill wastewater (OMW) by Lactobacillus paracasei, with and without pH adjustment by lime, was investigated. Mixtures OMW/CW at different proportions were fermented. The highest colour removal (47%) and total phenolic reduction (22.7%) of OMW were obtained after cofermentation of OMW/CW at proportions of 10/90, respectively. The decrease of pH after cofermentation of the two wastewaters, induced the precipitation of whey proteins with phenolic compounds and, so, improves decolorization. These removal yields reached 64% and 34%, respectively after precipitation by adjustment of pH at 7 with lime at the end of cofermentation. These improvements were correlated to a clarification of wastewaters by precipitation of whey proteins with phenolic compounds. An enhanced decolorization (up to 93%) and a total phenolic reduction (50%) of the mixture were obtained when cofermentation sequentially pH corrected by lime addition was investigated.