Smita Raghuvanshi

Experimental studies and kinetic modeling for removal of methyl ethyl ketone using biofiltration

The removal of toxic methyl ethyl ketone (MEK) is studied in a lab scale biofilter packed with mixture of coal and matured compost. The biofiltration operation is divided into 5 phases for a period of 60 days followed by shock loading conditions for three weeks. The maximum removal efficiency of 95% is achieved during phase II for an inlet concentration of 0.59 gm(-3), and 82-91% for the inlet concentration in the range of 0.45-1.23 gm(-3) of MEK during shock loads. The Michaelis-Menten kinetic constants obtained are 0.086 gm(-3)h(-1) and 0.577 gm(-3). The obtained experimental results are validated using Ottengraf-van den Oever model for zero-order diffusion-controlled region to understand the mechanism of biofiltration. The critical inlet concentration of MEK, critical inlet load of MEK and biofilm thickness are estimated using the results obtained from model predictions.

Biofiltration for removal of methyl isobutyl ketone (MIBK): experimental studies and kinetic modelling.

The present study deals with the biofiltration of methyl isobutyl ketone (MIBK), which is considered to be a highly toxic volatile organic compound. It is released from the paint and petrochemical industries and is one of the major contributors to air pollution. The biofiltration study was carried out on a lab scale for two months in the presence of acclimated mixed culture. The performance of the biofilter column was evaluated for different inlet loads of MIBK at air flow rates ranging from 0.18 to 0.3 m3 h−1. The maximum removal efficiency of 93% was obtained after 60 days of biofilter operation for an inlet MIBK concentration of 0.45 g m−3, and a microbial concentration of 2.36 × 108 CFU g−1 of packing material was obtained. This led to a study of shock loadings for 20 days, by varying the inlet MIBK load and air flow rate after every five days, to observe the behaviour of the biofilter column in removing sudden loads of MIBK. The biokinetic constants r max and K s were obtained using the Michaelis–Menten kinetics and were found to be 1.046 g m−3 and 0.115 g m−3 h−1, respectively, with a coefficient of determination (R 2) of 0.993. The obtained experimental results were validated with the Ottengraf and Van den Oever kinetic model. The critical inlet concentration, critical inlet load and biofilm thickness were also estimated using the results obtained from the model predictions.

Estimation of Kinetic Parameters for Bioremediation of Cr(VI) from Wastewater Using Pseudomonas taiwanensis, an Isolated Strain from Enriched Mixed Culture

ABSTRACT An aerobic mixed culture collected in the form of activated sludge was enriched for Cr(VI) reduction. An indigenous microorganism was isolated from the enriched aerobic mixed culture and identified as Pseudomonas taiwanensis. Bioremediation studies were carried out for treating Cr(VI)-contaminated wastewater using the indigenous microorganism. The kinetic studies were carried out for initial Cr(VI) concentrations ranging from 20 to 200 mg L−1. The maximum consumption of Cr(VI) obtained was 108.3 mg L−1 for an initial Cr(VI) concentration of 150 mg L−1 at a solution pH of 7.0. The effect of nutrient dosage and pH were studied to get their optimum values. The same isolated bacterial strain was also used to treat Cr(VI)-contaminated industrial wastewater collected from a local plating industry. Various growth kinetic models, such as Monod, Powell, Haldane, Luong, and Edward models, were fitted with the obtained experimental data. The obtained results for different growth kinetic models indicate that the growth kinetics of Pseudomonas taiwanensis for bioremediation of Cr(VI) can be better understood by the Luong model (R2 = .913). The rate kinetic analysis was performed using zero-order and three-half-order kinetic models. The three-half-order kinetic model was found to be suitable for the present bioremediation study.

Application of a hybrid biofilter column for the removal of Cr(VI) from aqueous solution using an indigenous bacterial strain Pseudomonas taiwanensis

ABSTRACT In the present study, a laboratory-scale biofilter column was designed and fabricated. It was packed with a mixture of coal and compost as a packing medium. The column was enriched with an indigenous bacterial strain Pseudomonas taiwanensis isolated from aerobic mixed culture of Sewage Treatment Plant, BITS-Pilani, Pilani campus. The removal of hexavalent chromium [Cr(VI)] from aqueous solution was investigated in the biofilter column. The entire biofiltration operation was divided into five phases (I to V) for a period of 63 days. Biofilter column was subjected to shock loading conditions for 20 days immediately after 63 days of operation. The maximum removal efficiency of 89.4% was obtained during phase V for Cr(VI) inlet concentration of 40 mg L−1. During shock loading, maximum removal efficiency was obtained as 90% for 48.5–50 mg L−1 of initial Cr(VI) concentration. Kinetic parameters of biofiltration process for Cr(VI) removal were also determined by fitting Michaelis-Menten kinetic model with experimental data. The Michaelis-Menten kinetic constants were obtained as 0.258 mg L−1 min−1 and 26.83 mg L−1. It was found that Ottengraf-Van den Oever model with zero-order diffusion limitation fit the experimental data quite well for phases III, IV, and V with coefficient of determination (R2) values .97, .99, and .984, respectively. A possible method for safe disposal of packing medium was also presented in this study.

Deducing the Bio-Perspective Capabilities of Fe(II) Oxidizing Bacterium Isolated from Extreme Environment

Rigorous utilization of chemical fertilizers, monoculture and irrigation with surface saline water is globally deteriorating the quality of surface soil. In present work, the halo and alkalo tolarent bacterium strain isolated from extreme environment, was explored for producing plant growth hormones, that could be used for salt stress up gradation of the crops. The 16S rRNA gene sequencing was used for analysis of salt tolerant bacterium. The bacterium was identified as Pseudomonas aeruginosa KP163922. The Pseudomonas aeruginosa KP 163922 showed plant growth promotion traits, production of industrially important enzymes (amylase, protease and cellulase) and tolerance to more than 4% NaCl. The antagonistic test reveals that, the growth of pathogenic gram negative bacterium E. coli and Pseudomonas putida was repressed by Pseudomonas aeruginosa KP163922.

Growth Kinetics of Acclimated Mixed Culture for Degradation of Isopropyl Alcohol (IPA)

Iso-propyl alcohol (IPA) is an organic chemical regarded as a potential pollutant. The permissible exposure limit (PEL) of IPA specified by Occupational Safety and Health Administration (OSHA) is 400 mg L-1. In this study the aerobic biodegradation of IPA is carried out by an acclimated mixed culture obtained by sewage treatment plant, for the range of 200-700 mg L-1 of initial IPA concentration. The batch degradation study demonstrated that the maximum growth rate obtainable is 0.337 h-1. To explain the inhibition effects, different kinetic growth models such as Haldane, Luong and Edward models are applied. The experimental data are found to fit well with inhibition models having the values of coefficient of determination (R2) of 0.989, 0.986 and 0.984 respectively for Haldane, Luong and Edward models. Based on the disappearance of IPA, degradation is modeled by the three-half-order kinetics and the resulting kinetic parameters are reported.

CHAPTER 3:Removal of Dissolved Metals by Bioremediation

Rapid industrialization has been adversely affecting the environment. Industrial effluents containing toxic and heavy metals are the main source of water contamination. Heavy metal pollution poses a serious environmental threat to humans and other living creatures due to the toxic effects of these metals and their accumulation throughout the food chain. In the last few decades, the concentration of these heavy metals in river water and sediments has been increasing at an alarming rate. Build-up of these toxic metals in vegetables grown in contaminated soils is posing adverse effects on human health. Numerous research projects on metal remediation through physico-chemical methods have been explored. However, most of these methods are either expensive or unsuitable for cases of voluminous effluents containing complex organic matter and low metal concentrations. In recent years, biological techniques have been shown to be a promising approach towards metal remediation in the laboratory and on an industrial scale. Microorganisms including bacteria, algae, fungi and yeasts can efficiently accumulate heavy metals from aqueous solutions, especially when the metal concentrations in the effluent ranges from less than 1 to 20 mg L−1. Biological systems employing processes such as bio-reduction, bioaccumulation or biosorption using dead/pretreated microbial biomass have been extensively studied for their roles in heavy metal removal from synthetic and industrial wastewater. However, many a times, biosorption alone may not suffice for an effective metal remediation technique when real industrial effluent is tested. Under such situations, application of living microbial cells might be a better option as they offer the ability of self-replenishment and the potential for optimization through development of resistant species and immobilization of the cell surface. These issues form the theme of the present chapter in addition to a brief overview of the various physico-chemical methods available and a detailed illustration of the bioremediation technique used for toxic metal detoxification. In addition, focus has also been given to the applicability of an enriched consortium of living metal-resistant cells for metal scavenging. This effort is directed towards the development of a green and economically viable technique for treatment of metal-rich effluents.

Biodegradation and biofiltration studies for removal of volatile organic compounds (VOCs)

K also called as metastin, is the cognate ligand GPR-54 (G-coupled receptor), which was previously an orphan receptor. Kisspeptin consists of 54 amino acids and its biological activity can be localized to the C-terminal segment which is cleaved into C-10, C-13, and C-14 segment. Kisspeptin-GPR-54 interaction stimulates GnRH secretion and has been shown to be essential for the initiation of the pubertal LH surge. A 14 amino acid derivative of kisspeptin (Asp-58-Val59-Ser60-Ala61-Tyr62Asn63-Trp64-Asn65-Ser66-Phe67-Gly68-Leu69-Arg70-Tyr71NH2) was synthesized by solid phase peptide synthesis using F-moc (9-fluorenyl methoxy carbonyl) strategy. Kisspeptin-14 was synthesized on Rinkamide resin after swelling it for 2h. Amino acid coupling steps were carried out by the treatment of deprotected resin with a 3 fold molar excess of F-moc protected amino acid, HBTU (O-Benzotriazole-N,N,N’,N’-tetramethyl-uronium-hexafluoro-phosphate) and HOBt (N-Hydroxybenzotriazole) for 2h at room temperature under constant shaking. Deprotection was carried out using 20% piperidine for 20 min under constant shaking. Between coupling and deprotection, the resin was washed twice with di-methyl formamide followed by three washing of di-chloromethane. Peptide was cleaved out of the resin using the cleavage mixture (Trifluoro acetic acid-82.5%, Thioanisole-5%, Ethanedithiol-5%, Water-10%, Phenol-5%). Kisspeptin peptide was purified by RP-HPLC using a gradient of 65-90% using C-18 column in binary gradient module consisting of 5% acetonitrile in water and a limiting organic solvent. The peptide was recovered directly after lyophilization. Peptide was evaluated for its secondary conformation by performing CD spectroscopy which showed primarily a random coil structure in water which can be induced to adopt more ordered conformation using solvent like tri-fluoroethanol.L hydrolysis of castor oil yields a high value product free from odour, colour and undesired side products, associated with conventional hydrolytic methods. However, use of immobilized lipase is limited by diffusional constraints of conventional two phase reaction media. Smart design of reaction media allowing oil homogenization was carried out in this study for hydrolysis of castor oil using indigenously immobilized lipases. Optimization of various parameters towards complete hydrolysis was carried out in batch experiments. Maximum hydrolysis of 85% was obtained for the reusable immobilized lipase preparation under packed bed conditions. The activity of immobilized enzyme for the said reaction under optimised conditions was observed to be >85% with no loss of activity for upto 10 cycles tested. The product so formed can be further converted to sugar alcohols, estolides, conjugated linolenic acids or lactones either by enzymatic/microbial methods. The advantage of biotransformation allows production of clean materials that find wider applicability and also higher commercial value.A are an important class of Pharmacological agents used for treating infections, which are a major cause of human morbidity and mortality. Although antibiotics were first isolated from fungi and bacteria (natural Source), but over the years more and more synthetic antibiotics are flowing in market. During the last two decades, the development of drug resistance as well as the appearance of undesirable side effects of certain antibiotics has lead to the search of new antimicrobial agent. There is ample of documented evidence which show antibiotic properties in plant extracts. The present study is based on antibacterial and antifungal activity of wildly growing indigenous plants. Aqueous and ethanol extract of different part ( leaves, flower, fruit, root) of Oxalis amara, Argemone maxicana, Datura inoxia, Calatropis procera , Amranthus, Pithecellobium dulce, Ziziphus mauritiana, Croton bonplandianum, Cannibus sativa, Leucaena leucophela, Andographis Peniculata were taken for study, against pathogenic bacteria Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and fungus Candida albicans. Results were observed/ calculated by their zone of inhibition after 24 hours by agar plate gel diffusion method. These plants are showing their antibacterial and antifungal activities, differently for different microorganism. This laboratory experiments has shown that plant extracts are effective against a broad spectrum of microbes (Both Gram positive and Gram negative bacteria and fungus) & antibiotics from Plant extracts (Herbal antibiotics) are promising agents for developing newer antibioticsT effect of increased industrialization has adverse impact on the environment thus leading to air pollution and water pollution. The major impact of industrial systems on the environment is the emissions of gaseous, liquid and particulate materials in the atmosphere which leads to air pollution. Air pollution is aggravated now-a-days because of economic development of societies across the world. The category of air emissions include the criteria pollutants given by the Environmental Protection Agency (EPA), USA which include sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), suspended particulate matter (SPM) and lead (Pb) which are significant contributors in the deterioration of public health (USEPA, 1993). Another important category of pollutants is hazardous pollutants such as Volatile Organic Compounds (VOCs), ammonia (NH3), hydrogen sulfide (H2S), etc. which are responsible for major air and water pollution. Out of all listed hazardous pollutants, VOCs are the large group of organic compounds emitted into the atmosphere by a wide range of industries. In fact, VOCs are one of the major pollutants released by the industries which contaminate the atmospheric air and the fresh water resources. This technique is widely used for the removal of VOCs from and air and metal ions from water. The potential of microorganisms in consuming the VOCs as carbon source makes biodegradation and biofiltration an attractive option for the removal of pollutants from the waste air and waste water streams. The work essentially discusses the biodegradation and biofiltration studies using the mixed culture. The work also discusses the essential factors for the development of the laboratory scale biofilter column and the packing material used in the biofiltration studies. The work also details in the various parameters such as effect of time, effect of flow rate, effect of shock loads and effect of bed height to check the performance of biofiltration. The work also incorporates the various applications of biofilters.F enzyme like Superoxide Dismutase (SOD: 1.15.1.1), has wide applications in the industry of pharmaceuticals, cosmetics, food and/or biotechnology. SOD is a primary antioxidant enzyme catalyzing the dismutation of superoxide free radical (O2-) (a disease causing agent). An important requirement for SODs intended for industrial applications is their thermal stability as thermal denaturation is a common cause of enzyme inactivation. In the present study, SOD has been isolated and characterized from Juglans regia (Walnut) kernels. The SOD enzyme obtained has been partially purified into two fractions based on 0-40% and 40-80% saturation level of ammonium sulphate; 0-40% fraction (72.46 Units/mg) having higher specific activity. The temperature optima of the partially purified SOD lied between 35oC to 40oC with thermo stability up to 70oC whereas the optimum value for pH being 5.0 with stability range of 4.0-7.0. All the tested detergents viz; Sodium Lauryl Sulphate (SLS), Cween-20 and Tween-80 and Tween-20 were found to inhibit the activity of enzyme, Cween-20 being most effective. Mg2+ and Ba2+ ions in the form of their respective salts, acted as potential inhibitors with about 50% reduction in enzyme activity. The results obtained herein indicate that J. regia (Walnut) kernel constitute an excellent source of SOD enzyme, which is an effective natural dietery antioxidant. It can be inferred from the present study that J. regia, a functional food, is a promising source of natural antioxidant (SOD) enzyme with potential application in oxidative stress-related diseases. The thermostability of the enzyme further enhances its importance making it industry friendly with high economical feasibility.H is routinely used in the treatment of pulmonary insufficiency and respiratory distress in preterm and term infants and in adults with acute respiratory disease (ARDS). However, in infants, hyperoxia contributes to the development of chronic lung disease (CLD), which is termed bronchopulmonary dysplasia (BPD). The molecular mechanisms of oxygen-mediated lung injury are not understood, but reactive oxygen species (ROS) are the most likely candidates. ROSare also responsible for many other lung diseases such as acute respiratory distress syndrome (ARDS), asthma, emphysema, chronic obstructive pulmonary disease (COPD), and lung cancer. Results from our laboratory demonstrate a novel role for cytochrome P450 (CYP)1A enzymes in the detoxification of ROS-mediated lipid peroxidation products, e.g., F2-isoprostanes. Our major observations are that mice lacking the genes for CYP1A1 or 1A2 are more susceptible to hyperoxic lung injury than wild type mice, with Cyp1a2-null mice being the most sensitive. On the other hand, mice lacking the gene for CYP1B1, are less susceptible to lung injury, suggesting a pro-oxidant role for CYP1B1. Mice pre-treated with the CYP1A inducer (β-napthoflavone (BNF), followed by exposure to hyperoxia leads to protection against lung injury. We also found formation of bulky oxidative lesions (oxidative DNA adducts) in tracheal aspirates of premature infants and adults who received supplemental oxygen, and this was associated with BPD and ARDS, thereby suggesting that these adducts could serve as novel biomarkers of these diseases. Future studies could lead to the development of rational strategies for the prevention/treatment of lung diseases associated with hyperoxia.S seeds of Sesamum indicum contain abundant oil, in particular, large amounts of unsaturated fatty acid oleic and linoleic acids. These unsaturated fatty acids lower the cholesterol level in the body. Because of their effects and antioxidant substances, attention has been paid to sesame seeds as health food. The regulation of fatty acid synthesis in oilseed crops is quite unknown. It is necessary to clarify these points to breed novel varieties with high contents of unsaturated fatty acids. Full-length cDNA libraries prepared from sesame seed of 1 to 3 weeks DAF, were subtracted with cDNAs from plantlets of 4 weeks after seeding. Each of 1,545 cDNA clones was sequenced. The function of novel genes expressed during the early maturation of sesame seeds was studied by the transformation of Arabidopsis thaliana. Thirteen genes for a transcription factor were identified; four were involved in ethylene signaling. Nine genes including aquaporin-like protein, putative uncharacterized novel protein and ethylene response factor were analyzed by overexpression of A. thaliana. A. thaliana overexpression strain for novel protein and aquaporin-like protein genes, respectively showed the increase of unsaturated fatty acids. The localization of these products was investigated by the induction of the expression vectors for GFP fusion protein into onion cells and sesame seeds with a particle gun.E pollution is considered as a side effect of modern industrial society. The presence of man-made (anthropogenic) organic compounds in the environment is a very serious public health problem. Phenol, an organic compound is toxic even at low concentrations and the toxicity of phenols for microbial cells has been investigated. Owing to the toxic nature and consequent health hazard of phenol, the need to remove it from waste waters. Harnessing the potential of microbes to degrade phenol has been an area of considerable study to develop bioremediation approaches, which is considered as “Green Option” for treatment of environmental contaminants. The optimum conditions for phenol degradation by Pseudomonas putida (NCIM 2102) were at inoculum size (6%v/v), pH (7), temperature (300C), agitation speed (140 rpm), glucose (0.8g/l), ammonium sulphate (1.5g/l), peptone (0.5g/l), and concentration of metal ion Mn2+(0.02 g/l).Central Composite Design (CCD) was employed combining with Response Surface Methodology (RSM) to optimize the physical, chemical parameters for the degradation of phenol by P. putida (NCIM 2102). Response Surface method was using three-levels of physico-chemical parameters like pH, temperature, agitation speed, carbon source (glucose), inorganic nitrogen source (ammonium sulfate) and metal ion (Mn2+) concentration which also enabled the identification of significant effects of interactions for the batch studies. The experimental values are in good agreement with predicted values and the correlation coefficient of physico-chemical parameters was found to be 0.9871, 0.9028 respectively.T Transport Phenomena in Food Materials laboratory at Purdue University seeks to establish the fundamental relationships between the structure of food materials and their mechanical and functional properties as influenced by processing, composition, and environmental conditions. A current research thrust area of this laboratory: Interfacial Phenomena in Foods seeks to establish a detailed understanding of interfacial mechanisms that affect the transport of mass and heat in food matrices, particularly in terms of developing enhanced food materials and processes. Two specific examples of research within this thrust area are: a) precise control of particle size during processing (e.g. emulsification, spray drying, microencapsulation, and nanomaterials) and storage (e.g. microsintering and coalescence) via modulation of dynamic interfacial conditions; and b) identifying novel capillary and interfacial mechanisms for enhancing drying rates in porous food matrices. Advances in this area enabled by insights achieved through combinations of experimental tools (such as high-speed visualization and laser Doppler velocimetry) and recent computational modeling tools (such as first-principles approaches and direct numerical simulations) will be presented.