Biosequestration of lignin in municipal landfill leachate by tailored cationic lipoprotein biosurfactant through Bacillus tropicus valorized tannery solid waste.

Bioremediation of municipal landfill leachate (MLL) is often intricate due to presence of refractory lignin. In the present study, it was attempted to tailor the histidine rich protein moiety of cationic lipoprotein biosurfactant (CLB) to sequester the lignin from MLL. Animal fleshing (AF), the solid waste generated in tanning industry was utilized for the production of histidine rich CLB by de novo substrate dependent synthesis pathway involving Bacillus tropicus. The optimum conditions for the maximum production of CLB were determined using response surface methodology. At the optimized conditions, the maximum yield of CLB was 217.4 mg/g AF (on dry basis). The produced histidine rich CLB was purified using Immobilized metal affinity chromatography at the optimum binding and elution conditions. The histidine residues were more pronounced in the CLB, as determined by HPLC analysis. The CLB was further characterized by SDS-PAGE, Zeta potential, XRD, FT-IR, Raman, NMR, GC-MS and TG analyses. The CLB was immobilized onto functionalized nanoporous activated bio carbon (FNABC) and the optimum immobilization capacity was found to be 211.6 mg/g FNABC. The immobilization of CLB onto FNABC was confirmed using SEM, FT-IR, XRD and TG analyses. The isotherm models, kinetic and thermodynamics studies of CLB immobilization onto FNABC were performed to evaluate its field level application. Subsequently, the CLB-FNABC was then applied for the sequestration of lignin in MLL. The maximum lignin sequestration was achieved by 92.5 mg/g CLB-FNABC at the optimized sequestration time, 180 min; pH, 5; temperature, 45 °C and mass of CLB-FNABC, 1.0 g. The sequestration of lignin by CLB- FNABC was confirmed by SEM, FT-IR and UV-Vis analyses. Further, the mechanistic study revealed the anchoring of CLB onto the surface of lignin through electrostatic interaction.

Metals in coarse ambient aerosol as markers for source apportionment and their health risk assessment over an eastern coastal urban atmosphere in India.

Ambient PM10 (particulate matter with aerodynamic diameter ≤ 10 µm) samples were collected and characterized from July 2012 to August 2013 with the objective to evaluate the variation in elemental concentration and use the same as markers for source apportionment and health risk assessment for the first time over Bhubaneswar, India. The yearly average mass of PM10 was 82.28 µg/m3, which was ~ 37% higher than the national ambient air quality (NAAQ) standards. Maximum PM10 concentration was observed during winter season followed by post-monsoon, pre-monsoon, and monsoon months. Acid soluble components in the PM10 samples were analyzed using ICP-OES (inductive coupled plasma optical emission spectroscopy), and 19 different elements including heavy metals were determined. Enrichment factor analysis attributed the source to either crustal or non-crustal origin. Principal component analysis (PCA) revealed that crustal sources, industrial activities, and vehicular emissions were significant contributors to PM mass. The contribution of total average elemental concentration showed a seasonal variation with the lowest (11.96 µg/m3) and highest (17.77 µg/m3) during monsoon and winter, respectively, which is relatively less significant than the variation in total PM10 mass that ranged between 48.43 µg/m3 in monsoon and 138.24 µg/m3 during the winter season. This observation evidences the predominant contribution of local/regional emission sources to the metallic components in coarse PM10 mass, which is corroborated by the wind pattern studies carried out using polar plots and a Lagrangian Particle Dispersion Model (LPDM) FLEXPART. Further, carcinogenic and non-carcinogenic health risk assessments of the measured elements that find their way into the human body through different exposure pathways have been calculated using United State Environmental Protection Agency (USEPA) standards. The carcinogenic risk of most of the elements was insignificant. The potential risk assessment study revealed that regular exposure to heavy metals through the ingestion pathway caused detrimental health effects. These effects were observed to be more severe in children in comparison to adults.

Antioxidant and antimicrobial activity of bioactive prodigiosin produces from Serratia marcescens using agricultural waste as a substrate.

The objective of this investigation was to explore the antioxidant and antimicrobial property of bioactive prodigiosin produced from Serratia marcescens using rice bran. The antioxidant potential of prodigiosin was examined by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2'-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical scavenging method via UV-visible, electron spin resonance spectrum (ESR), cyclic voltammetry and excitation emission spectrum. The antimicrobial activity of prodigiosin was examined against foodborne pathogens. The shelf life extending capacity of prodigiosin was evaluated with meat extract powder (MEP) as a model food material. The DPPH and ABTS radicals were completely scavenged by prodigiosin at the concentration of 10 mg/L. The food spoilage was inhibited by the addition of prodigiosin with MEP and it was compared with conventional preservative. The prodigiosin has prohibited the growth of foodborne pathogens effectively and the shelf life of the food was also extended significantly. The antimicrobial edible preservative developed in this study inhibited the growth of the microbial populations that produced through storage of the MEP and free radical scavenging activity. The results reveal that the bioactive prodigiosin effectively scavenged the free radical and inhibited the bacterial growth in food stuff.

Separation of sodium chloride from the evaporated residue of the reverse osmosis reject generated in the leather industry--optimization by response surface methodology.

Reverse osmosis (RO) concentrate is being evaporated by solar/thermal evaporators to meet zero liquid discharge standards. The resulted evaporated residue (ER) is contaminated with both organic and inorganic mixture of salts. The generation of ER is exceedingly huge in the leather industry, which is being collected and stored under the shelter to avoid groundwater contamination by the leachate. In the present investigation, a novel process for the separation of sodium chloride from ER was developed, to reduce the environmental impact on RO concentrate discharge. The sodium chloride was selectively separated by the reactive precipitation method using hydrogen chloride gas. The selected process variables were optimized for maximum yield ofNaCl from the ER (optimum conditions were pH, 8.0; temperature, 35 degrees C; concentration of ER, 600 g/L and HCl purging time, 3 min). The recovered NaCl purity was verified using a cyclic voltagramm.

Extractive membrane bioreactor (EMBR): Recent advances and applications.

Combining bioreactor and membrane, known as a membrane bioreactor (MBR), has been considered as an attractive strategy to solve the limitations of conventional activated sludge process, such as biological instability, poor sludge quality, and low concentration of mixed liquor suspended solid. Unlike the other MBRs, extractive membrane bioreactor (EMBR) focuses on enhancing the efficiency of wastewater treatment through toxic compounds extraction by using a selective membrane. Even though EMBR has been successfully demonstrated in wastewater and waste gas treatment by several studies, it still faces some obstacles such as biofilm formation and low selectivity of the membrane towards a specific component. Appropriate biofilm formation control strategies and membrane with high selectivity are needed to solve those problems. This paper reviews EMBR including its potential applications in wastewater treatment, denitrification process, and waste gas treatment. In addition, challenges and outlook of EMBR are discussed.

Comparison of cognitive functions between people with silent and wild-type butyrylcholinesterase.

In the human brain, butyrylcholinesterase (BuChE) is expressed in neurons and glia. For example, many nuclei in the human thalamus, with projections to the cerebral cortex, contain a large number of neurons with intense BuChE activity. Thalamocortical projections subserve a variety of cognitive functions. Due to genetic mutations, there are individuals who do not have detectable BuChE activity (silent BuChE). While the prevalence of silent BuChE is only 1:100,000 in European and American populations, it is 1:24 in the Vysya community in Coimbatore, India. To examine whether there are differences in cognitive functions between individuals with silent BuChE and those expressing normal BuChE (wild-type), twelve healthy individuals with silent BuChE and thirteen healthy individuals with wild-type BuChE, all from the Vysya community in Coimbatore, were tested for cognitive function using the Automated Neuropsychological Assessment Metrics test battery. The silent BuChE group was slightly faster on simple reaction tasks, but slower on a visual perceptual matching task. Furthermore, discriminant function analyses correctly classified 11/12 silent and 8/13 wild-type BuChE subjects (76% correct classification overall) based on BuChE status. Different profiles of cognitive test performance between individuals with silent and wild-type BuChE were observed. These observations suggest a function for BuChE in cognition.

Effects of temperature, salinity, and carbon: nitrogen ratio on sequencing batch reactor treating shrimp aquaculture wastewater.

In order to improve the water quality in the shrimp aquaculture, we tested a sequencing batch reactor (SBR) for the treatment of shrimp wastewater. A SBR is a variation of the activated sludge biological treatment process. This process uses multiple steps in the same tank to take the place of multiple tanks in a conventional treatment system. The SBR accomplishes pH correction, aeration, and clarification in a timed sequence, in a single reactor basin. This is achieved in a simple tank, through sequencing stages, which includes fill, react, settle, decant, and idle. The wastewater from the Waddell Mariculture Center, South Carolina was successfully treated using a SBR. The wastewater contained high concentration of carbon and nitrogen. By operating the reactor sequentially, viz, aerobic, anaerobic, and aerobic modes, nitrification and denitrification were achieved as well as removal of carbon. We optimized various environmental parameters such as temperature, salinity, and carbon and nitrogen ratio (C:N ratio) for the best performance of SBR. The results indicated that the salinity of 28-40 parts per thousand (ppt), temperature range of 22-37 degrees C, and a C:N ratio of 10:1 produced best results in terms of maximum nitrogen and carbon removal from the wastewater. The SBR system showed promising results and could be used as a viable treatment alternative in the shrimp industry.

Synthesis of Surface-Modified Iron Oxides for the Solvent-Free Recovery of Bacterial Bioactive Compound Prodigiosin and Its Algicidal Activity.

Prodigiosin (PG) is a bioactive compound produced by several bacterial species. Currently, many technologies are being developed for the production of PG by fermentation processes. However, new challenges are being faced with regard to the production of PG in terms of the recovery and purification steps, owing to the labile nature of PG molecules and the cost of the purification steps. Conventional methods have limitations due to high cost, low reusability, and health hazards. Hence, the present investigation was focused on the development of surface-functionalized magnetic iron oxide ([Fe3O4]F) for solvent-free extraction of bioactive PG from the bacterial fermented medium. Fe3O4 was functionalized with diethanolamine and characterized by FT-IR, diffuse reflectance spectroscopy, thermogravimetric analysis, scanning electron microscopy, and confocal microscopy. The various process parameters, such as contact time, temperature, pH, and mass of Fe3O4, were optimized for the extraction of PG using functionalized Fe3O4. Instrumental analyses confirmed that the PG molecules were cross-linked with functional groups on [Fe3O4]F through van der Waals forces of attraction. PG extracted through Fe3O4 or [Fe3O4]F was separated from the fermentation medium by applying an external electromagnetic field and regenerated for successive reuse cycles. The purity of the extracted PG was characterized by high-performance liquid chromatography, FT-IR, and UV-visible spectroscopy. The iron oxide-diethanolamine-PG cross-linked ([Fe3O4]F-PG) composite matrix effectively deactivates harmful fouling by cyanobacterial growth in water-treatment plants. The present investigation provides the possibility of solvent-free extraction of bacterial bioactive PG from a fermented medium using functionalized magnetic iron oxide.

On the multifunctionality of cholinesterases.

Here we present novel information on non-classical functions of cholinesterases and on a cross-talk linking the two enzymes AChE and BChE. The first part of the article is focussed on the regulation of ChEs and the effects acquired when one of the proteins is knocked down (siRNA for BChE, AChE knock-out mouse). In the second part evidence is presented showing that AChE may exert adhesive properties through its binding to laminin, thus being involved in cell-matrix or cell-cell communication.

In situ generation of hydroxyl radical by cobalt oxide supported porous carbon enhance removal of refractory organics in tannery dyeing wastewater.

In this study, cobalt oxide doped nanoporous activated carbon (Co-NPAC) was synthesized and used as a heterogeneous catalyst for the Fenton oxidation of organic dye chemicals used in tannery process. The nanoporous activated carbon (NPAC) was prepared from rice husk by precarbonization followed by chemical activation at elevated temperature (600 °C). The cobalt oxide was impregnated onto NPAC and characterized for UV-visible, Fluorescence spectroscopy, FT-IR, HR-TEM, XRD, BET surface area and XPS analyses. The hydroxyl radical generation potential of Co-NPAC from hydrogen peroxide decomposition was identified (λ(exi), 320 nm; λ(emi), 450 nm) by Excitation Emission Spectra (EES) analysis. The conditions for the degradation of tannery dyeing wastewater such as, Co-NPAC dose, concentration of H2O2, and temperature were optimized in heterogeneous Fenton oxidation process and the maximum percentage of COD removal was found to be 77%. The treatment of dyes in wastewater was confirmed through UV-Visible spectra, EES and FT-IR spectra analyses.

A direct method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels.

BACKGROUND: In vertebrates, two types of cholinesterases exist, acetylcholinesterase and butyrylcholinesterase. The function of acetylcholinesterase is to hydrolyse acetylcholine, thereby terminating the neurotransmission at cholinergic synapse, while the precise physiological function of butyrylcholinesterase has not been identified. The presence of cholinesterases in tissues that are not cholinergically innervated indicate that cholinesterases may have functions unrelated to neurotransmission. Furthermore, cholinesterases display a genuine aryl acylamidase activity apart from their predominant acylcholine hydrolase activity. The physiological significance of this aryl acylamidase activity is also not known. The study on the aryl acylamidase has been, in part hampered by the lack of a specific method to visualise this activity. We have developed a method to visualise the aryl acylamidase activity on cholinesterase in polyacrylamide gels. RESULTS: The o-nitroaniline liberated from o-nitroacetanilide by the action of aryl acylamidase activity on cholinesterases, in the presence of nitrous acid formed a diazonium compound. This compound gave an azo dye complex with N-(1-napthyl)-ethylenediamine, which appeared as purple bands in polyacrylamide gels. Treating the stained gels with trichloroacetic acid followed by Tris-HCl buffer helped in fixation of the stain in the gels. By using specific inhibitors for acetylcholinesterase and butyrylcholinesterase, respectively, differential staining for the aryl acylamidase activities on butyrylcholinesterase and acetylcholinesterase in a sample containing both these enzymes has been demonstrated. A linear relationship between the intensity of colour developed and activity of the enzyme was obtained. CONCLUSIONS: A novel method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels has been developed.

Distinct Effect of Benzalkonium Chloride on the Esterase and Aryl Acylamidase Activities of Butyrylcholinesterase.

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) from vertebrates, other than their predominant acylcholine hydrolase (esterase) activity, display a genuine aryl acylamidase activity (AAA) capable of hydrolyzing the synthetic substrate o-nitroacetanilide to o-nitroaniline. This AAA activity is strongly inhibited by classical cholinesterase (ChE) inhibitors. In the present study, benzalkonium chloride (BAC), a cationic detergent widely used as a preservative in pharmaceutical preparations, has been shown to distinctly modulate the esterase and AAA activities of BChEs. The detergent BAC was able to inhibit the esterase activity of human serum and horse serum BChEs and AChEs from electric eel and human erythrocyte. The remarkable property of BAC was its ability to profoundly activate the AAA activity of human serum and horse serum BChEs but not the AAA activity of AChEs. Thus BAC seem to preferentially activate the AAA activity of BChEs alone. Results of the study using the ChE active site-specific inhibitor diisopropyl phosphorofluoridate indicated that BAC binds to the active site of ChEs. Furthermore, studies using a structural homolog of BAC indicated that the alkyl group of BAC is essential not only for its interaction with ChEs but also for its distinct effect on the esterase and AAA activities of BChEs. This is the first report of a compound that inhibits the esterase activity, while simultaneously activating the AAA activity, of BChEs. Copyright 2000 Academic Press.

Process optimization for enhanced production of diphtheria toxin by submerged cultivation.

When stationary culture was replaced by submerged cultivation in a fermentor, a significant increase in the yield of diphtheria toxin in a short cultivation time (less than 48 h as against 7-8 d) was noted. It was found that under optimal conditions of temperature, vortex mixing and surface aeration, an alkaline pH favoured toxin release. Furthermore, to enhance the production volume, two-and three-step semicontinuous batch cultivations were carried out. The toxin produced was of good titre with an adequate antigenic purity. Under optimal conditions, the variation in the Limes of flocculation (Lf titre) was likely due to the quality of the production medium, which in turn depended on the quality of the raw materials used. The process was also optimized in a pilot-scale fermentor.

Enhanced biodegradation of cyclotetramethylenetetranitramine (HMX) under mixed electron-acceptor condition.

The biodegradation of cyclotetramethylenetetranitramine, commonly known as 'high melting explosive' (HMX), under various electron-acceptor conditions was investigated using enrichment cultures developed from the anaerobic digester sludge of Thibodaux sewage treatment plant. The results indicated that the HMX was biodegraded under sulfate reducing, nitrate reducing, fermenting, methanogenic, and mixed electron accepting conditions. However, the rates of degradation varied among the various conditions studied. The fastest removal of HMX (from 22 ppm on day 0 to < 0.05 ppm on day 11) was observed under mixed electron-acceptor conditions, followed in order by sulfate reducing, fermenting, methanogenic, and nitrate reducing conditions. Under aerobic conditions, HMX was not biodegraded, which indicated that HMX degradation takes place under anaerobic conditions via reduction. HMX was converted to methanol and chloroform under mixed electron-acceptor conditions. This study showed evidence for HMX degradation under anaerobic conditions in a mixed microbial population system similar to any contaminated field sites, where a heterogeneous population exists.

Anaerobic degradation of No. 2 diesel fuel in the wetland sediments of Barataria-Terrebonne estuary under various electron acceptor conditions.

The biodegradation of No. 2 diesel fuel under anaerobic conditions was investigated using sediments collected from wetlands of Barataria-Terrebonne estuary in Louisiana. The results indicated enhanced biodegradation of diesel fuel under sulfate-reducing, nitrate-reducing, methanogenic, and mixed electron acceptor conditions. However, the rate of diesel degradation was the highest under mixed electron acceptor conditions followed in order by sulfate-reducing, methanogenic, and nitrate-reducing conditions. Under mixed electron acceptor condition, 99% removal of diesel fuel was achieved within 510 days, while under sulfate-reducing condition 62% degradation of diesel fuel was observed for the same period. Diesel fuel was also degraded to a smaller extent in the culture condition where electron acceptors were not supplemented (natural attenuation condition). This study showed evidence for enhanced diesel fuel metabolism in a mixed microbial population system similar to any contaminated field site, where a heterogeneous microbial population exists.

Anaerobic biodegradation of no. 2 diesel fuel in soil: a soil column study.

Soil and sediments are contaminated with petroleum hydrocarbons in many parts of the world. Anaerobic degradation of petroleum hydrocarbon is very relevant in removing oil spills in the anaerobic zones of soil and sediments. This research investigates the possibility of degrading no. diesel fuel under anaerobic conditions. Anaerobic packed soil columns were used to simulate and study in situ bioremediation of soil contaminated with diesel fuel. Several anaerobic conditions were evaluated in soil columns, including sulfate reducing, nitrate reducing, methanogenic, and mixed electron acceptor conditions. The objectives were to determine the extent of diesel fuel degradation in soil columns under various anaerobic conditions and identify the best conditions for efficient removal of diesel fuel. Diesel fuels were degraded significantly under all conditions compared to no electron supplemented soil column (natural attenuation). However, the rate of diesel degradation was the highest under mixed electron acceptor conditions followed in order by sulfate reducing, nitrate reducing, and methanogenic conditions. Under mixed electron acceptor condition 81% of diesel fuel was degraded within 310 days. While under sulfate reducing condition 54.5% degradation of diesel fuel was observed for the same period. This study showed evidence for diesel fuel metabolism in a mixed microbial population system similar to any contaminated field sites, where heterogeneous microbial population exists.

Anaerobic biotransformation of carbon tetrachloride under various electron acceptor conditions.

The biotransformation of carbon tetrachloride (CT) under various electron acceptor conditions was investigated using enrichment cultures developed from the anaerobic digester sludge of Thibodaux sewage treatment plant. The results indicated that CT was biotransformed under sulfate-reducing, methanogenic, nitrate-reducing, iron-reducing, fermenting, and mixed electron acceptor conditions. However, the rates of CT removal varied among the conditions studied. The fastest removal of CT (100% removal in 12 days) was observed under mixed electron acceptor conditions followed in order by sulfate-reducing, methanogenic, fermenting, iron-reducing, and nitrate-reducing conditions. Under mixed electron acceptor conditions, the CT was converted to methyl chlorides, which was further metabolized. Under sulfate, iron, nitrate-reducing, and methanogenic conditions, the major metabolite produced from CT metabolism was chloroform (CF). Under fermenting conditions, methylene chloride was produced from CT metabolism. This study showed evidence for CT metabolism in a mixed microbial population system similar to many contaminated field sites where a heterogeneous microbial population exists.

Microbial decomposition of post-harvest sugarcane residue.

A laboratory in situ composting study was conducted as a possible alternative method for the current practice of open air burning of post-harvest sugarcane residue by sugarcane farmers. In situ composting of the sugarcane residue by the indigenous bacteria and fungi was accelerated using molasses as an initial substrate. A one-time application of molasses boosted the soil microbial population. which started to decompose the ligno-cellulosic fractions of the residue. The study showed significant differences in several parameters among the control and molasses applied treatments, namely, visual decomposition of residue, bacterial and fungal population, soil pH, cellulose content, cellulase activity. and soil organic matter. Further study is needed to refine the process for the future application of this technology as a possible alternative to the current practice of open air burning of sugarcane residue by farmers.

Effect of food-grade surfactant on bioremediation of explosives-contaminated soil.

The use of native soil bacteria to biodegrade explosives-contaminated soil under co-metabolic conditions has been demonstrated. The addition of food-grade surfactants could improve the process by enhancing the rates of explosives desorption from soil, thereby increasing the bioavailability of explosives for microbial degradation. The objective of this study was to decrease residence time in the slurry reactor, thereby increasing output and reducing clean-up costs. In this study, Tween 80 (monooleate), served not only as a surfactant but also as the carbon substrate for the soil microorganisms. Four 2l soil slurry reactors were operated in batch mode with soil containing 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The results indicated that TNT and RDX were removed in all reactors except the control (no added carbon source). The reactor enriched with surfactant and molasses performed better than reactors with either molasses or surfactant alone. The TNT and its metabolite, 4-amino-2,6-dinitrotoluene were removed faster in the reactor with surfactant plus molasses (35 days) than in the reactor with molasses alone as carbon source (45 days). A radiolabeling study of the mass balance of TNT in the slurry reactors showed substantial mineralization of TNT to CO2.

Chemical modification studies of Rhizomucor miehei protease: evidence for the role of basic amino acids in enzyme catalysis.

The effect of chemical modification on milk clotting and proteolytic activities of aspartyl protease obtained from Rhizomucor miehei NRRL 3500 was examined in the absence and the presence of its specific inhibitor pepstatin A. The effect on the ratio of milk clotting activity (MC) to proteolytic activity (PA), an index of the quality of milk clotting proteases was also determined. Modification of the enzyme with trinitrobenzenesulfonic acid, diethylpyrocarbonate and phenylglyoxal produced an increase in the ratio of MC/PA, while modification with 2- hydroxy-5-nitrobenzyl bromide did not affect the ratio. Modification with N-acetylimidazole resulted in a marginal increase in MC/PA ratio. Protection using pepstatin A during modification with phenylglyoxal, N-acetylimidazole and 2-hydroxy-5-nitrobenzyl bromide, protected both MC and PA. In the case of modification by diethylpyrocarbonate, pepstatin A protected only MC. Pepstatin A did not protect both the activities on the modification of the enzyme by trinitrobenzene sulfonic acid. These observations indicate the presence of arginine, tyrosine and tryptophan at the catalytic site of the enzyme, for eliciting MC and PA of the enzyme. In general, modification of the positively charged residues increases the MC/PA ratio of the enzyme. In addition the modified lysine residues responsible for the inactivation of the enzyme were not involved in the active site of the enzyme. Thus the lysine residues might have a secondary role in enzyme catalysis. Further, histidine at the catalytic site was found to be exclusively involved in milk clotting activity. The enzyme with modified histidine residues were more susceptible to autocatalysis, indicating that histidine residues protect the enzyme against autolysis.