Department of Chemical Engineering
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Item Reforming CO2 bio-mitigation utilizing Bacillus cereus from hypersaline realms in pilot-scale bubble column bioreactor(Springer, 2024-03) Raghuvanshi, Smita; Gupta, SureshThe bubble column reactor of 10 and 20 L capacity was designed to bio-mitigate 10% CO2 (g) with 90% air utilizing thermophilic bacteria (Bacillus cereus SSLMC2). The maximum biomass yield during the growth phase was obtained as 9.14 and 10.78 g L−1 for 10 and 20 L capacity, respectively. The maximum removal efficiency for CO2 (g) was obtained as 56% and 85% for the 10 and 20 L reactors, respectively. The FT-IR and GC–MS examination of the extracellular and intracellular samples identified value-added products such as carboxylic acid, fatty alcohols, and hydrocarbons produced during the process. The total carbon balance for CO2 utilization in different forms confirmed that B. cereus SSLMC2 utilized 1646.54 g C in 10 L and 1587 g of C in 20 L reactor out of 1696.13 g of total carbon feed. The techno-economic assessment established that the capital investment required was $286.21 and $289.08 per reactor run of 11 days and $0.167 and $0.187 per gram of carbon treated for 10 and 20 L reactors, respectively. The possible mechanism pathways for bio-mitigating CO2 (g) by B. cereus SSLMC2 were also presented utilizing the energy reactions. Hence, the work presents the novelty of utilizing thermophilic bacteria and a bubble column bioreactor for CO2 (g) bio-mitigation.Item A comprehensive review of flue gas bio-mitigation: chemolithotrophic interactions with flue gas in bio-reactors as a sustainable possibility for technological advancements(Springer, 2024-04) Raghuvanshi, Smita; Gupta, SureshFlue gas mitigation technologies aim to reduce the environmental impact of flue gas emissions, particularly from industrial processes and power plants. One approach to mitigate flue gas emissions involves bio-mitigation, which utilizes microorganisms to convert harmful gases into less harmful or inert substances. The review thus explores the bio-mitigation efficiency of chemolithotrophic interactions with flue gas and their potential application in bio-reactors. Chemolithotrophs are microorganisms that can derive energy from inorganic compounds, such as carbon dioxide (CO2), nitrogen oxides (NOx), and sulfur dioxide (SO2), present in the flue gas. These microorganisms utilize specialized enzymatic pathways to oxidize these compounds and produce energy. By harnessing the metabolic capabilities of chemolithotrophs, flue gas emissions can be transformed into value-added products. Bio-reactors provide controlled environments for the growth and activity of chemolithotrophic microorganisms. Depending on the specific application, these can be designed as suspended or immobilized reactor systems. The choice of bio-reactor configuration depends on process efficiency, scalability, and ease of operation. Factors influencing the bio-mitigation efficiency of chemolithotrophic interactions include the concentration and composition of the flue gas, operating conditions (such as temperature, pH, and nutrient availability), and reactor design. Chemolithotrophic interactions with flue gas in bio-reactors offer a potentially efficient approach to mitigating flue gas emissions. Continued research and development in this field are necessary to optimize reactor design, microbial consortia, and operating conditions. Advances in understanding the metabolism and physiology of chemolithotrophic microorganisms will contribute to developing robust and scalable bio-mitigation technologies for flue gas emissions.Item Sustainable synergistic approach to chemolithotrophs—supported bioremediation of wastewater and flue gas(Springer Nature, 2024-07) Raghuvanshi, Smita; Gupta, SureshFlue gas emissions are the waste gases produced during the combustion of fuel in industrial processes, which are released into the atmosphere. These identical processes also produce a significant amount of wastewater that is released into the environment. The current investigation aims to assess the viability of simultaneously mitigating flue gas emissions and remediating wastewater in a bubble column bioreactor utilizing bacterial consortia. A comparative study was done on different growth media prepared using wastewater. The highest biomass yield of 3.66 g L−1 was achieved with the highest removal efficiencies of 89.80, 77.30, and 80.77% for CO2, SO2, and NO, respectively. The study investigated pH, salinity, dissolved oxygen, and biochemical and chemical oxygen demand to assess their influence on the process. The nutrient balance validated the ability of bacteria to utilize compounds in flue gas and wastewater for biomass production. The Fourier Transform–Infrared Spectrometry (FT–IR) and Gas Chromatography–Mass Spectrometry (GC–MS) analyses detected commercial-use long-chain hydrocarbons, fatty alcohols, carboxylic acids, and esters in the biomass samples. The nuclear magnetic resonance (NMR) metabolomics detected the potential mechanism pathways followed by the bacteria for mitigation. The techno-economic assessment determined a feasible total capital investment of 245.74$ to operate the reactor for 288 h. The bioreactor’s practicability was determined by mass transfer and thermodynamics assessment. Therefore, this study introduces a novel approach that utilizes bacteria and a bioreactor to mitigate flue gas and remediate wastewater.Item Assessing the bacterial consortium's potential to bio-mitigate CO2 and SO2 from simulated flue gas, wastewater bioremediation, and product characterization(Elsevier, 2024-12) Raghuvanshi, Smita; Gupta, SureshThe present study aims to fix carbon dioxide (CO2) and sulfur dioxide (SO2) simultaneously by conducting extensive semi-continuous experiments on the 3 L glass bioreactor to evaluate the potential of bacterial consortium for CO2 (C), SO2 (S), and CO2 + SO2 (CS) gaseous mixture. In this study, the bacterial consortium (Bacillus tropicus SSLMC1, Bacillus cereus SSLMC2) utilizes thiosulfate as an energy source and domestic wastewater (DWW) supplemented with additional minerals as a nutrient source. The maximum CO2 and SO2 mitigation efficiency was obtained as 93.8 % and 91.4 % for CS and S gaseous mixtures, respectively. The biomass concentration, biomass productivity, removal efficiency, and utilization efficiency for the CS gas mixture are comparable with the C and S gas mixture. Simultaneously, various nutrients and pollutants such as BOD, COD, PO43- and CO32- were removed. Fourier Transform Infrared Spectroscopy (FT-IR) and Gas Chromatography-Mass spectroscopy (GC-MS) analysis of cell lysate and cell-free supernatant have indicated the presence of fatty alcohols and long-chain hydrocarbons in all three gaseous mixtures. The present study showed that bacterial consortia can bio-mitigate CO2 and SO2 simultaneously and implement the bio-mitigation study of CO2 and SO2 in a real scenarioItem Biofiltration: Essentials, Research and Applications(Wiley, 2012-03) Raghuvanshi, Smita; Gupta, SureshItem Defluoridation studies using graphene oxidebased nanoadsorbents(Elsevier, 2021) Raghuvanshi, Smita; Gupta, SureshThe groundwater of many developed and developing countries including India has reported excessive fluoride concentrations. Various technologies are being used to remove fluoride from water but still the problem has remained unsolved. Among the available different technologies, adsorption is one of the best methods due to its easy handling, high efficiency, and lower cost. Adsorption technique with the application of nanoadsorbents has become more efficient, as the adsorption capacity is found to increase significantly due to the large surface area provided by the nanoparticles. Since the last few years, nanomaterial-related technologies have gained much attention in the field of water treatment. The previous studies have discussed the possible mechanism for fluoride ion adsorption on nanoparticles. This chapter discusses the possibility of magnesium oxide nanoparticles as adsorbents for the removal of fluoride from wastewater. This chapter demonstrated the use of modified Hummers' method for synthesizing nano-magnesium oxide (n-MgO) and nanocomposites (n-MgO-coated GOs). The developed adsorbents were characterized using various methods such as FTIR, XRD, SEM-EDX, TEM, etc. The effect of various influencing parameters such as initial pH, initial fluoride concentration, adsorbent dosage, and contact time on fluoride adsorption using developed adsorbents was studied. This chapter demonstrated the efficient removal of fluoride ions from aqueous solution using n-MgO and nanocomposites.Item Remediation of Waste Engine Oil Contaminated Soil using Rhamnolipid based Detergent Formulation(Elsevier, 2023) Jain, Amit; Gupta, Suresh; Chattopadhyay, PradiptaThe utilization of waste substrates for rhamnolipid synthesis is a worthy alternative to conventional substrates to reduce the production cost of rhamnolipids. Rhamnolipid produced by Pseudomonas aeruginosa gi |KP 163922| using waste engine oil as substrate was investigated in batch and semi-batch studies for soil bioremediation. Green liquid detergent formulations were prepared by using environment-friendly builder (sodium citrate) and filler (isopropyl alcohol). Rhamnolipid, a biosurfactant was utilized in place of chemical surfactant to prepare the liquid detergent formulation. The formulations at different rhamnolipid concentrations i.e., below critical micelle concentration (CMC), at CMC, and above CMC, were tested for soil remediation efficiency. Each detergent formulation was characterized based on emulsification index (EI24%), surface tension reduction, foam ability, and foam stability. The in-house rhamnolipid based formulations above CMC, recovered oil up to 82.02 ± 0.938 % from contaminated soil with maximum surface tension reduction and foam volume as 26.5 ± 0.412 mN/m and 51.10 ± 1.37 mL respectively. The proposed remediation strategy demonstrated that the recovery of oil is possible at room temperature conditions. The performance properties including detergency and foaming of rhamnolipid based liquid detergent formulations were also compared with commercial rhamnolipid and other detergents.Item Production, characterization, and kinetic modeling of biosurfactant synthesis by Pseudomonas aeruginosa gi |KP 163922|: a mechanism perspective(Springer, 2023-05) Jain, Amit; Gupta, SureshKinetic studies and modeling of production parameters are essential for developing economical biosurfactant production processes. This study will provide a perspective on mechanistic reaction pathways to metabolize Waste Engine Oil (WEO). The results will provide relevant information on (i) WEO concentration above which growth inhibition occurs, (ii) chemical changes in WEO during biodegradation, and (iii) understanding of growth kinetics for the strain utilizing complex substrates. Laboratory scale experiments were conducted to study the kinetics and biodegradation potential of the strain Pseudomonas aeruginosa gi |KP 163922| over a range (0.5–8% (v/v)) of initial WEO concentration for 168 h. The kinetic models, such as Monod, Powell, Edward, Luong, and Haldane, were evaluated by fitting the experimental results in respective model equations. An unprecedented characterization of the substrate before and after degradation is presented, along with biosurfactant characterization. The secretion of biosurfactant during the growth, validated by surface tension reduction (72.07 ± 1.14 to 29.32 ± 1.08 mN/m), facilitated the biodegradation of WEO to less harmful components. The strain showed an increase in maximum specific growth rate (µmax) from 0.0185 to 0.1415 h−1 upto 49.92 mg/L WEO concentration. Maximum WEO degradation was found to be ~ 94% gravimetrically. The Luong model (adj. R2 = 0.97) adapted the experimental data using a non-linear regression method. Biochemical, 1H NMR, and FTIR analysis of the produced biosurfactant revealed a mixture of mono- and di- rhamnolipid. The degradation compounds in WEO were identified using FTIR, 1H NMR, and GC–MS analysis to deduce the mechanism.Item Valorization of waste engine oil to mono- and di-rhamnolipid in a sustainable approach to circular bioeconomy(Springer, 2024-04) Jain, Amit; Gupta, SureshThis study aims to valorize waste engine oil (WEO) for synthesizing economically viable biosurfactants (rhamnolipids) to strengthen the circular bioeconomy concept. It specifically focuses on investigating the influence of key bioprocess parameters, viz. agitation and aeration rates, on enhancing rhamnolipid yield in a fed-batch fermentation mode. The methodology involves conducting experiments in a stirred tank bioreactor (3 L) using Pseudomonas aeruginosa gi |KP 163922| as the test organism. Central composite design and response surface methodology (CCD-RSM) are employed to design the experiments and analyze the effects of agitation and aeration rates on various parameters, including dry cell biomass (DCBM), surface tension, tensoactivity, and rhamnolipid yield. It is also essential to determine the mechanistic pathway of biosurfactant production followed by the strain using complex hydrophobic substrates such as WEO. The study reveals that optimal agitation and aeration rates of 200 rpm and 1 Lpm result in the highest biosurfactant yield of 29.76 g/L with minimal surface tension (28 mN/m). Biosurfactant characterization using FTIR, 1H NMR, and UPLC-MS/MS confirm the presence of dominant molecular ion peaks m/z 543.9 and 675.1. This suggests that the biosurfactant is a mixture of mono- and di-rhamnolipids (RhaC10C10, RhaRhaC10C12:1, RhaRhaC12:1C10). The findings present a sustainable approach for biosurfactant production in a fed-batch bioreactor. This research opens the possibility of exploring the use of pilot or large-scale bioreactors for biosurfactant production in future investigations.Item Characterization and oil recovery application of biosurfactant produced during bioremediation of waste engine oil by strain Pseudomonas aeruginosa gi|KP 16392| isolated from Sambhar salt lake(Taylor & Francis, 2021-05-05) Jain, Amit; Gupta, SureshHalophilic bacterium, Pseudomonas aeruginosa gi|KP 16392| isolated from Sambhar salt lake in the southwest region of the city of Jaipur, India was tested for the first time for potential application in waste engine oil bioremediation and simultaneous biosurfactant production. In this study, the batch experiments were performed on culture grown in mineral salt medium supplemented with 5% (v/v) waste engine oil as the sole carbon source incubated for a week at pH 7.0, maintaining 35 °C and 150 rpm. The bacterial growth was monitored by the optical density and dry biomass content measurements. The biosurfactant production was affirmed with the reduction in surface tension of the culture medium from 72 ± 0.36 to 29.61 ± 0.14 mN/m. Of the total waste engine oil fed, 74.35 ± 0.037% was consumed and biodegraded to secondary metabolites. The biosurfactant yield was found to be approximately 1.02 g/L. The functional groups in the product, identified with the Fourier transform infrared spectroscopy confirms to be rhamnolipid and characterized using microbial adhesion to hydrocarbon (math) test and methyl assay. The emulsification activity of the produced biosurfactant was assessed for various hydrophobic substrates and was found to be comparable to the chemical surfactant (sodium dodecyl sulfate). The biosynthetic pathway (de novo synthesis) used by microbial strain to form rhamnolipid is schematically represented. The performance of the purified biosurfactant in oil recovery application was tested using a simulated waste engine oil contaminated soil and it showed excellent surface activity.