[Show abstract][Hide abstract] ABSTRACT: To cite this article: Rashmi Paliwal, Shivani Uniyal, Megha Verma, Amit Kumar & J.P.N. Rai (2015): Process optimization for biodegradation of black liquor by immobilized novel bacterial consortium, Desalination and Water Treatment, A B S T R A C T Present investigation deals with the optimization of biodegradation process of black liquor (BL) performed by novel bacterial consortium which consist of two indigenous bacterial strains viz., Bacillus megaterium ETLB-1 and Pseudomonas plecoglossicida ETLB-3. During the process, dextrose as carbon; sodium nitrate as nitrogen; C:N ratio (2.5:1); temperature (35˚C); pH (8.0); and agitation rate (160 rpm) were observed as optimum conditions for bacterial consortium. Further, these conditions were assessed for the performance of immobilized consortium that exhibit conspicuous reduction in color (96.1%), lignin (91.5%), biological oxygen demand (96.7%), and chemical oxygen demand (86.4%) of black liquor. A maximum percent reduction of 90.7% in chlorophenols (up to 10.03 mg/L) with highest release of chloride ions i.e. 1,233 mg/L was recorded under optimum conditions. Bioligni-nolytic activities with the presence of lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (LAC) was observed as 6.94 U/ml, 9.35, and 8.96 U/ml at different time intervals viz. 120, 144, and 96 h, respectively, during the biodegradation study. Further, gas chromatography/mass spectroscopy revealed presence of certain organic acids, degradation of majority of the toxic compounds, and generation of certain high-value compounds.
Full-text · Article · Oct 2015 · Desalination and water treatment
[Show abstract][Hide abstract] ABSTRACT: Rapidly increasing human population, urbanization, industrialization, and mining activities have become
the serious environmental issue of today’s world. Conventional physico-chemical remediation methods
are highly expensive and generate secondary waste. However, bioremediation of contaminated ecosystems
using indigenous microbes and plants or amalgamation of both has been recognized as a cost effective
and eco-friendly method for remediation as well as restoration of polluted or degraded ecosystems.
Further, variety of pollutant attenuation mechanisms possessed by microbes and plants makes them
more feasible for remediation of contaminated land and water over physico-chemical methods. Plants
and microbes act cooperatively to improve the rates of biodegradation and biostabilization of environmental
contaminants. This chapter aims to emphasize on potential application of microbes and plants
to attenuate the organic and inorganic pollutants from the contaminated sites as well as eco-restoration
of mine degraded and jhum lands by way of biodegradation and phytoremediation technologies.
[Show abstract][Hide abstract] ABSTRACT: Lignin is the second most abundant natural polymeric carbon source on earth after cellulose. It is a
plant-originated polymer with three-dimensional network of dimethoxylated (syringyl), monomethoxylated (guaiacyl), and non-methoxylated (phydroxyphenyl) phenylpropanoid and acetylated units. The structural complexity and insolubility of lignin make it highly recalcitrant for degradation. Its biological degradation is critical to the global carbon cycle. Bioligninolysis involves application of microorganisms and their enzymes in degradation of lignin which provide environmental friendly technology for various industrial applications. As a major repository of aromatic chemical structures, lignin bears paramount significance for its removal from woody plants/lignocellulosic material, owing to potential application of bioligninolytic systems on commercial scale. This chapter provides an overview of microbial ligninolysis and its role in carbon cycling, various industrial process and pollution abatement for natural ecosystem management.
[Show abstract][Hide abstract] ABSTRACT: Two indigenous bacterial strains, Bacillus megaterium ETLB-1 (accession no. KC767548) and Pseudomonas plecoglossicida ETLB-3 (accession no. KC767547), isolated from soil contaminated with paper mill effluent, were co-immobilized on corncob cubes to investigate their biodegradation potential against black liquor (BL). Results exhibit conspicuous reduction in color and lignin of BL upto 913.46 Co-Pt and 531.45 mg l(-1), respectively. Reduction in chlorophenols up to 12 mg l(-1) was recorded with highest release of chloride ions, i.e., 1290 mg l(-1). Maximum enzyme activity for lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (LAC) was recorded as 5.06, 8.13, and 8.23 U ml(-1), respectively, during the treatment. Scanning electron microscopy (SEM) revealed successful immobilization of bacterial strains in porous structures of biomaterial. Gas chromatography/mass spectroscopy (GC/MS) showed formation of certain low molecular weight metabolites such as 4-hydroxy-benzoic acid, 3-hydroxy-4-methoxybenzaldehyde, ferulic acid, and t-cinnamic acid and removal of majority of the compounds (such as teratogenic phthalate derivatives) during the period of treatment. Results demonstrated that the indigenous bacterial consortium possesses excellent decolorization and lignin degradation capability which enables its commercial utilization in effluents treatment system.
Full-text · Article · Nov 2014 · Environmental Science and Pollution Research
[Show abstract][Hide abstract] ABSTRACT: The aim of present study was to remediate chromium (Cr)-contaminated soil by Crotalaria juncea in the presence of Pseudomonas fluorescens. Inoculation of P. fluorescens in pot soil grown with C. juncea significantly increased (~2-fold) the water-soluble (Ws) and exchangeable (Ex) Cr contents in contaminated soil under greenhouse condition. It also enhanced the chlorophyll content by 92 % and plant biomass by 99 % as compared to the uninoculated C. juncea plant. The analysis showed that root and shoot uptake of Cr in C. juncea inoculated by P. fluorescens was 3.08- and 2.82-fold, respectively. This research showed that the association of C. juncea and P. fluorescens could be a promising technology for increasing the soil Cr bioavailability and plant growth for successful phytoextraction of Cr from the contaminated soil.
No preview · Article · Mar 2014 · Environmental Science and Pollution Research
[Show abstract][Hide abstract] ABSTRACT: Biodegradation of α, β, γ and δ hexachlorocyclohexane (HCH) isomers was studied in broth medium and soil microcosm by Bacillus circulans and Bacillus brevis isolated from contaminated soil. Degradation of α and γ isomers by both the bacterial isolates was higher than thermodynamically stable β and δ isomers. However, B. circulans was found more effective than B. brevis for β and δ isomers. Maximum rate of degradation was recorded at 150 mg/L followed by 100 and 50 mg/L. Soil microcosm study revealed maximum degradation of HCH isomers in the treatment containing natural soil, pesticide and bacterial inocula than the treatment having sterilised soil, pesticide and bacterial isolates. Chloride release was positively co-related with HCH degradation in broth medium as well as in soil microcosm, suggesting that B. circulans and B. brevis hold promising potential by having efficient enzyme(s) required for dechlorination of HCH from contaminated sites.
No preview · Article · Feb 2014 · Chemistry and Ecology
[Show abstract][Hide abstract] ABSTRACT: An experiment was conducted to evaluate the phytoremediation potential of Eichornia crassipes exposed to different dilutions (i.e., 25%, 50% and 75%) of brass and electroplating industry effluent. A supporting experiment was also conducted in parallel with synthetic binary and single metal solutions of Cd and Cr to assess their impact on growth of plants. The maximum removal of heavy metals was observed under 50% dilution effluent (i.e., 89% for Cd and 87% for Cr) followed by 75% (i.e. 81% for Cd and 77% for Cr) and 25% (i.e. 51% for Cd and 50% for Cr) dilutions. Richard's model fitted to shoot growth data showed highest growth and rate in 50% diluted effluent (k=0.372; Kc=0.49 for Cd and 0.45 for Cr). The study suggested that E. crassipes can be a good plant species for remediation of water bodies moderately contaminated with brass and electroplating industry effluent.
[Show abstract][Hide abstract] ABSTRACT: In the present study, the biosorption capacity of Stenotrophomonas humi and Micrococcus luteus has been assessed for removal of cadmium from the synthetic solution under varying Cd2+ concentrations (50–250 ppm), pH (2–8), and contact time (10–270 min). The maximum biosorption capacity (qm) of S. humi and M. luteus were 97.08 and 42.55 mg/g at 30°C, respectively. The experimental isotherm data were analyzed using the Langmuir, Freundlich and Dubinin–Radushkevich (D–R) equations. The equilibrium data fit well in the Freundlich isotherm for S. humi and M. luteus. The RL values ranged between 0 and 1, and rate constant value of Cd2+ uptake demonstrated its efficient removal from the solution. Kinetic study showed that pseudo-second-order model describes the biosorption process better than the Lagergren pseudo-first-order and intraparticle diffusion model. The thermodynamic parameters such as free energy, entropy, and enthalpy change for the adsorption of Cd2+ have also been computed and discussed. Based on D–R isotherm value, physiosorption appears to be one of the major mechanisms for adsorption of Cd2+ by the bacteria. The interactions between heavy metals and functional groups on the cell wall surface of bacterial biomass were confirmed by Fourier transform infrared spectroscopy (FTIR) analysis, which indicate the possible removal of Cd2+ ions from the environment by S. humi and M. luteus.
No preview · Article · Dec 2013 · Desalination and water treatment
[Show abstract][Hide abstract] ABSTRACT: Biosorption of Cu(2+), Zn(2+), and Cr(6+) from aqueous solutions by leaf biomass of Jatropha curcas was investigated as a function of biomass concentration, initial metal ion concentration, contact time, and pH of the solution systematically. The aim of this study was to optimize biosorption process and find out a suitable kinetic model for the metal removal in single and multi-metal system. The experimental data were analyzed using two sorption kinetic models, viz., pseudo-first- and pseudo-second-order equations, to determine the best fit equation for the biosorption of metal ions Cu(2+), Zn(2+), and Cr(6+) onto the leaf biomass of J. curcas in different metal systems. The experimental data fitted well the pseudo-second-order equation and provided the best correlation for the biosorption process. The findings of the present investigation revealed that J. curcas leaf biomass was an eco-friendly and cost-effective biosorbent for the removal of heavy metal ions from wastewater.
No preview · Article · Oct 2013 · Environmental Monitoring and Assessment
[Show abstract][Hide abstract] ABSTRACT: The equilibrium sorption of Cr(VI) and Cu(II) from aqueous solution using Jatropha curcas deoiled cake, has been studied with respect to adsorbent dosage, contact time, pH, and initial metal concentration in batch mode experiments. Removal of Cu(II) by deoiled cake was greater than that of Cr(VI). The adsorbent chemical characteristics, studied by Fourier transform-infrared analysis, suggested that the presence of Cr(VI) and Cu(II) in the biomass influenced the bands corresponding to hydroxyl and carboxyl groups. Desorption studies revealed that maximum metals recovery was achieved by HNO3 followed by CH3COOH and HCl. The Freundlich isotherm model showed good fit to the equilibrium adsorption data. The adsorption kinetics followed the pseudo-second-order model, which provided the best correlation for the biosorption process, and suggested that J. curcas deoiled cake can be used as an efficient biosorbent over other commonly used sorbents for decontamination of Cr(VI)- and Cu(II)-containing wastewater.
No preview · Article · Aug 2013 · Water Environment Research
[Show abstract][Hide abstract] ABSTRACT: Chromate-resistant bacterial strain isolated from the soil of tannery was studied for Cr(VI) bioaccumulation in free and immobilised cells to evaluate its applicability in chromium removal from aqueous solution. Based on the comparative analysis of the 16S rRNA gene, and phenotypic and biochemical characterization, this strain was identified as Paenibacillus xylanilyticus MR12. Mechanism of Cr adsorption was also ascertained by chemical modifications of the bacterial biomass followed by Fourier transform infrared spectroscopy analysis of the cell wall constituents. The equilibrium biosorption analysed using isotherms (Langmuir, Freundlich and Dubinin-Redushkevich) and kinetics models (pseudo-first-order, second-order and Weber-Morris) revealed that the Langmuir model best correlated to experimental data, and Weber-Morris equation well described Cr(VI) biosorption kinetics. Polyvinyl alcohol alginate immobilised cells had the highest Cr(VI) removal efficiency than that of free cells and could also be reused four times for Cr(VI) removal. Complete reduction of chromate in simulated effluent containing Cu(2+), Mg(2+), Mn(2+) and Zn(2+) by immobilised cells, demonstrated potential applications of a novel immobilised bacterial strain MR12, as a vital bioresource in Cr(VI) bioremediation technology.
No preview · Article · Jan 2013 · Environmental Science and Pollution Research
[Show abstract][Hide abstract] ABSTRACT: Bacterial isolates from endosulfan-contaminated soil were grown in minimal medium and screened for endosulfan degradation. The isolate which used endosulfan and showed maximum growth was selected for detailed study. Maximum degradation in shake flask culture by Pseudomonas fluorescens was 92.80% of α and 79.35% of β endosulfan isomers in 15 days at 20 mg/L concentration, followed by 50 and 100 mg/L, while the corresponding values in static condition were 69.15 and 51.39%, respectively. Endosulfan concentration degradation declined significantly at 50 and 100 mg/L. Concomitant to degradation, release of chloride ion exhibited positive relation, while pH decreased from 7.0 to 4.53 in agitating and 7.0–5.18 in static condition. The soil microcosm study revealed maximum endosulfan degradation in sterilized soil amended with P. fluorescens. Endosulfan diol and endosulfan ether were among the products of endosulfan metabolism in broth culture, but only endosulfan ether was detected in the soil microcosm. Endosulfan sulphate, a persistent and toxic metabolite of endosulfan, was not detected in either case. The study showed that P. fluorescens could be used effectively for bioremediation of the pesticide contaminated sites.
No preview · Article · Oct 2012 · International Journal of Environmental Studies
[Show abstract][Hide abstract] ABSTRACT: The present investigation aims to optimize dose and pattern of distillery effluent for sugarcane irrigation. The postmethanated distillery effluent (PMDE) was recorded to have significant amount of micro- (Na, Zn, Fe) and macro- (Ca, Mg, N-NO3, P, K, S–SO) nutrients and so was utilized for sugarcane irrigation. Lysimetric studies were conducted to assess the impact of PMDE on sugarcane productivity with different concentrations (50 and 75%) and irrigation patterns (intermittent and pre-sowing). The intermittent pattern of ferti-irrigation with 50 and 75% effluent dose for sugarcane crop was found to enhance the growth and quality parameters of crop without impairing the groundwater quality. Results were more pronounced with 75% intermittent irrigation as the percent increase with respect to control for plant length, cane girth, cane weight, number of internodes per cane, dry matter accumulation, juice extraction, sucrose content, and available sugar were 28.0, 42.5, 14.6, 40.2, 54.4, 18.9, 44.9, 57.9, and 50.0%, respectively. It is suggested that PMDE can be used as an alternative of fresh water irrigation and also as a fertilizer for sugarcane, provided that the effluent quality and sugarcane quality is continuously monitored to avoid any contamination.
No preview · Article · Aug 2012 · CLEAN - Soil Air Water
[Show abstract][Hide abstract] ABSTRACT: Bioligninolysis involves living organisms and/or their products in degradation of lignin, which is highly resistant, plant-originated polymer having three-dimensional network of dimethoxylated (syringyl), monomethoxylated (guaiacyl), and non-methoxylated (p-hydroxyphenyl) phenylpropanoid and acetylated units. As a major repository of aromatic chemical structures on earth, lignin bears paramount significance for its removal owing to potential application of bioligninolytic systems in industrial production. Early reports illustrating the discovery and cloning of ligninolytic biocatalysts in fungi was truly a landmark in the field of enzymatic delignification. However, the enzymology for bacterial delignification is hitherto poorly understood. Moreover, the lignin-degrading bacterial genes are still unknown and need further exploration. This review deals with the current knowledge about ligninolytic enzyme families produced by fungi and bacteria, their mechanisms of action, and genetic regulation and reservations, which render them attractive candidates in biotechnological applications.
Full-text · Article · May 2012 · Applied biochemistry and biotechnology
[Show abstract][Hide abstract] ABSTRACT: The present investigation was carried out to isolate bacterial strains from soil/mud samples of metal-polluted environment to check whether the natural adaptation of microbes has equipped them for bioremediation of toxic heavy metals. The primary and secondary screening resulted in 50 mesophilic autotrophic isolates of microbial consortium adapted for metal tolerance and bioadsorption potentiality. The multimetal tolerance in bacterial strain was developed by sequential transfer to higher concentrations of Cd, Cr, Cu, Pb, Ni, and Zn. The isolates were checked for their biosolubilization potential with copper-containing metal sulfide ores, viz. chalcopyrite exhibited 64% and covellite 54% solubilization in the presence of 10 M multiple heavy metals on the fifth day at 35°C and pH 6.0. Metal adsorption of highly potential isolate, i.e., Paenibacillus validus MP5, studied by inductively coupled plasma optical emission spectroscopy (ICP-OES), showed maximum adsorption of Zn 27%, followed by Ni and Cd 16%, Cr 15%, Co 9%, and Pb 7.5% in chalcopyrite, which suggested its possible role in decontamination of metal-polluted sites.
No preview · Article · Apr 2012 · Bioremediation Journal
[Show abstract][Hide abstract] ABSTRACT: Bacterial isolates from endosulfan-contaminated soil were grown in minimal medium and screened for endosulfan degradation. The isolate which used endosulfan and showed maximum growth was selected for detailed study. Maximum degradation in shake flask culture by Pseudomonas fluores-cens was 92.80% of α and 79.35% of β endosulfan isomers in 15 days at 20 mg/L concentration, followed by 50 and 100 mg/L, while the corresponding values in static condition were 69.15 and 51.39%, respectively. Endosulfan concentration degradation declined significantly at 50 and 100 mg/L. Concomitant to degradation, release of chloride ion exhibited positive relation, while pH decreased from 7.0 to 4.53 in agitating and 7.0–5.18 in static condition. The soil microcosm study revealed maximum endosulfan degradation in sterilized soil amended with P. fluorescens. Endosul-fan diol and endosulfan ether were among the products of endosulfan metabolism in broth culture, but only endosulfan ether was detected in the soil microcosm. Endosulfan sulphate, a persistent and toxic metabolite of endosulfan, was not detected in either case. The study showed that P. fluo-rescens could be used effectively for bioremediation of the pesticide contaminated sites.
[Show abstract][Hide abstract] ABSTRACT: The impact assessment of molasses-based distillery-effluent irrigation on groundwater quality around village Gajraula in the district of Jyotiba Phule Nagar, Uttar Pradesh, India was studied by sampling groundwater on monthly intervals consecutively for summer, winter and monsoon seasons during 2006–2007 and water quality parameters, viz. pH, electrical conductivity (EC), chloride (Cl−), sulphate (SO), nitrate (NO), chemical oxygen demand (COD), total solids (TS), total dissolved solids (TDS), sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), zinc (Zn2+), iron (Fe3+), and total coliforms (TC) were monitored. Results depicted that the values of all parameters decreased with increasing depth of water table. Sulphate, nitrate and potassium contents were maximal in agricultural site during monsoon while EC, Cl−, TS, TDS, Na+, Ca2+, Mg2+, Zn, and Fe were maximal in industrial sites during summer. Groundwater samples of residential site harboured maximum coliforms especially during monsoon, highlighting threat to groundwater. Significant positive correlation matrix between coliforms with nitrate, sulphate and potassium ions explained their survival on these nutrients. To overcome this, important measures emphasizing improvement in effluent treatment technology matching site-specific characteristics are recommended for eco-friendly ferti-irrigation.
No preview · Article · Jul 2010 · CLEAN - Soil Air Water
[Show abstract][Hide abstract] ABSTRACT: The phytoextraction potential of water hyacinth (Eichchornia crassipes) was assessed for the removal of selenium and copper individually and from binary solutions. Plant growth, estimated on day 16 of metal treatment, decreased at all concentrations of selenium (2–12 ppm), whereas it increased at lower concentrations of copper (4–12 ppm) and decreased at higher exposure levels. Unlike copper, the rate constant for selenium uptake and its accumulation factors, calculated for both root and shoot, were lower in a binary solution than in the corresponding single-metal solution. Analysis of the elemental composition of the plant revealed that in single-metal copper treatment, the level of Mg decreased with a higher magnitude, followed by K and Ca. However, in the case of selenium, the Ca level increased, Mg remained unaffected and the K level decreased with increasing exposure. Our results revealed that a water hyacinth-based system could successfully remove selenium and copper from water/wastewater.
No preview · Article · Jun 2010 · Chemistry and Ecology
[Show abstract][Hide abstract] ABSTRACT: The dead Kluyveromyces marxianus biomass, a fermentation industry waste, was used to explore its sorption potential for lead, mercury, arsenic, cobalt, and cadmium as a function of pH, biosorbent dosage, contact time, agitation speed, and initial metal concentration. The equilibrium data fitted the Langmuir model better for cobalt and cadmium, but Freundlich isotherm for all metals tested. At equilibrium, the maximum uptake capacity (Qmax) was highest for lead followed by mercury, arsenic, cobalt, and cadmium. The RL values ranged between 0-1, indicating favorable sorption of all test metals by the biosorbent. The maximum Kf value of Pb showed its efficient removal from the solution. However, multi-metal analysis depicted that sorption of all metals decreased except Pb. The potentiometric titration of biosorbent revealed the presence of functional groups viz. amines, carboxylic acids, phosphates, and sulfhydryl group involved in heavy metal sorption. The extent of contribution of functional groups and lipids to biosorption was in the order: carboxylic>lipids>amines>phosphates. Blocking of sulfhydryl group did not have any significant effect on metal sorption.
No preview · Article · Oct 2009 · Biotechnology Journal