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Hydrothermal liquefaction (HTL) is an attractive thermochemical pathway that converts microalgal cells into biocrude which can be upgraded and refined into drop-in transportation fuel. HTL is propitious from an environmental sustainability standpoint because the reaction requires medium temperatures (200–400 °C) and high pressures (5–25 MPa) (subcritical and supercritical conditions) for a relatively short period of time (10–60 min) without the need for dewatering and drying of the microalgal culture (wet microalgae with cultivation culture). Instead, water provides dual use to the reaction: as a solvent and as a catalyst. At HTL conditions, water is a reactive nonpolar species with high miscibility in organics. It solubilizes even the recalcitrant microalgal components such as lignin to produce biocrude, aqueous, gaseous, and solid products. This chapter discusses the process and chemistry of microalgae HTL, the role of water in the reaction, the difference between catalytic and non-catalytic HTL as it applies to microalgae, and perspectives and direction on the state of research for microalgae HTL.
Eleazer P. Resurreccion; Sandeep Kumar. Catalytic and Non-Catalytic Hydrothermal Liquefaction of Microalgae. Catalysis for Clean Energy and Environmental Sustainability 2021, 149 -183.
AMA StyleEleazer P. Resurreccion, Sandeep Kumar. Catalytic and Non-Catalytic Hydrothermal Liquefaction of Microalgae. Catalysis for Clean Energy and Environmental Sustainability. 2021; ():149-183.
Chicago/Turabian StyleEleazer P. Resurreccion; Sandeep Kumar. 2021. "Catalytic and Non-Catalytic Hydrothermal Liquefaction of Microalgae." Catalysis for Clean Energy and Environmental Sustainability , no. : 149-183.
Protein-rich spent yeast is a waste by-product of brewing and other fermentation industry. A continuous-flow hydrothermal treatment called ‘flash hydrolysis’ was deployed for protein recovery and yeast disposal. A feed slurry with 1-15 wt% yeast was hydrolyzed at temperatures ranging between 160-280 °C for a very short residence time of 10±2 s. Using 10 wt% yeast at 240 °C, 66.5% carbon, 70.4% nitrogen and 61.0% overall yeast biomass was solubilized in liquid hydrolysate. The liquid hydrolysate in which 63.1% of analyzed amino acids in yeast feed were solubilized, was tested as nutrient for cultivation of E. coli in a continuous bioreactor. The steady-state E. coli concentration was 1.18 g L-1 and 0.93 g L-1 using liquid hydrolysate and commercial yeast extract, respectively. Finally, the kinetic parameters for yeast solubilization (reaction order, activation energy and pre-exponential factor) were found to be 0.86, 21.3 kJ mol-1 and 19.36 [L g-1]n-1 s-1, respectively.
Anuj Thakkar; Elena Barbera; Eleonora Sforza; Alberto Bertucco; Ryan Davis; Sandeep Kumar. Flash hydrolysis of yeast (Saccharomyces cerevisiae) for protein recovery. The Journal of Supercritical Fluids 2021, 173, 105240 .
AMA StyleAnuj Thakkar, Elena Barbera, Eleonora Sforza, Alberto Bertucco, Ryan Davis, Sandeep Kumar. Flash hydrolysis of yeast (Saccharomyces cerevisiae) for protein recovery. The Journal of Supercritical Fluids. 2021; 173 ():105240.
Chicago/Turabian StyleAnuj Thakkar; Elena Barbera; Eleonora Sforza; Alberto Bertucco; Ryan Davis; Sandeep Kumar. 2021. "Flash hydrolysis of yeast (Saccharomyces cerevisiae) for protein recovery." The Journal of Supercritical Fluids 173, no. : 105240.
Background. Lead (Pb(II)) exposure from drinking water consumption is a serious concern due to its negative health effect on human physiology. A commercially available filter uses the adsorption potential of activated carbon for removing heavy metals like Pb(II). However, it has some constraints since it uses only surface area for the adsorption of these contaminants. Biochar produced via slow pyrolysis of biomass shows the presence of oxygen-containing functional groups on its surface that take part in the adsorption process, with higher removal potential compared to activated carbon. Objectives. The current study examined the adsorption kinetics and mechanisms of Pb(II) removing potential of biochar from water using a fixed-bed continuous flow adsorption system. Methods. The effect of initial Pb(II) concentration, mass of adsorbent (bed depth), and flow rate on adsorption potential were evaluated. The Adams-Bohart model, Thomas model, and Yoon-Nelson model were applied to the adsorption data. Results. The maximum removal efficiency of Pb(II) was 88.86 mg/g. The result illustrated that the Yoon-Nelson model is the best fit to analyze the adsorption phenomena of Pb(II) in a fixed-bed biochar column. Conclusions. The breakthrough data obtained from this study can be utilized to design a point of use filter that would be able to effectively remove Pb(II) from drinking water. Competing Interests. The authors declare no competing financial interests.
Pushpita Kumkum; Sandeep Kumar. Evaluation of Lead (Pb(II)) Removal Potential of Biochar in a Fixed-bed Continuous Flow Adsorption System. Journal of Health and Pollution 2020, 10, 1 .
AMA StylePushpita Kumkum, Sandeep Kumar. Evaluation of Lead (Pb(II)) Removal Potential of Biochar in a Fixed-bed Continuous Flow Adsorption System. Journal of Health and Pollution. 2020; 10 (28):1.
Chicago/Turabian StylePushpita Kumkum; Sandeep Kumar. 2020. "Evaluation of Lead (Pb(II)) Removal Potential of Biochar in a Fixed-bed Continuous Flow Adsorption System." Journal of Health and Pollution 10, no. 28: 1.
To overcome the inefficient biomass conversion, waste generation, and lack of co-production in biorefineries, an integrated process was proposed for the conversion of corn stover into levulinic acid and biocarbon electrode material. Corn stover was pretreated through hydrothermal process using 0.45 wt% K2CO3 which removed 76 wt% lignin and 85 wt% xylan while preserving 83 wt% glucan. This was followed by acid hydrolysis to produce levulinic acid at varying H2SO4 concentrations and reaction time in a batch reactor at 190 °C. At a reaction time of 5 min in 2 wt% H2SO4, 35.8 wt% and 30 wt% glucan in raw and pretreated corn stover was converted to levulinic acid, respectively. The residue from acid hydrolysis was converted into biocarbon for supercapacitor electrodes via a two-step thermal activation process which showed a specific capacitance of 120 F g−1. The proposed integrated biorefinery concept provides multiple value-added products for a greater financial and environmental sustainability.
Anuj Thakkar; Katelyn M. Shell; Martino Bertosin; Dylan D. Rodene; Vinod Amar; Alberto Bertucco; Ram B. Gupta; Rajesh Shende; Sandeep Kumar. Production of levulinic acid and biocarbon electrode material from corn stover through an integrated biorefinery process. Fuel Processing Technology 2020, 213, 106644 .
AMA StyleAnuj Thakkar, Katelyn M. Shell, Martino Bertosin, Dylan D. Rodene, Vinod Amar, Alberto Bertucco, Ram B. Gupta, Rajesh Shende, Sandeep Kumar. Production of levulinic acid and biocarbon electrode material from corn stover through an integrated biorefinery process. Fuel Processing Technology. 2020; 213 ():106644.
Chicago/Turabian StyleAnuj Thakkar; Katelyn M. Shell; Martino Bertosin; Dylan D. Rodene; Vinod Amar; Alberto Bertucco; Ram B. Gupta; Rajesh Shende; Sandeep Kumar. 2020. "Production of levulinic acid and biocarbon electrode material from corn stover through an integrated biorefinery process." Fuel Processing Technology 213, no. : 106644.
Oil-laden biofuel intermediate (BI) from flash-hydrolyzed microalgae was characterized, pyrolyzed, and subjected to catalytic transfer hydrogenation (CTH) to produce both gaseous and liquid hydrocarbon fuels. The BI was characterized by TGA and FTIR that revealed significant triglyceride, evidenced by CO bond with insignificant level of carbohydrates and proteins. Thermogravimetric analysis (TGA) indicated that the BI could be thermally decomposed at 400 °C. Pyrolysis of the BI engendered mainly gaseous hydrocarbon (alkenes) with high heating value (HHV) of 48.5 kJ/mol at 850 °C. Energy of activation for the pyrolytic process was estimated to be 115–300 kJ/mol. Optimization of oil extraction from the BI was performed via design of experiment. The oil was subjected to CTH over NiOx-CoOx-MoOx-zeolite using 2-propanol as hydrogen donor in a 30-ml batch reactor at a temperature range of 390–420 °C and autogenic pressure of 24–27 bar, leading to fatty acid conversion of 99–100%. The main liquid products obtained from the CTH were iso-alkanes (41%), cyclo-alkanes (35%), aromatics (5%), n-alkanes (14%), and alkenes (5%). Kinetics of the CTH showed first order with activation energy of 176 kJ/mol. The catalyst was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunaeur-Emmett-Teller (BET) adsorption and desorption, scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and TGA. The catalyst revealed cubic structure, which was maintained after 5 h of CTH reaction. Present in both the fresh and the used catalysts were oxides of alkali and transition metals. The active sites of the catalyst were dominated by Co3+, Ni2+, and Mo6+.
Alexander Asiedu; Ryan Davis; Sandeep Kumar. Catalytic transfer hydrogenation and characterization of flash hydrolyzed microalgae into hydrocarbon fuels production (jet fuel). Fuel 2019, 261, 116440 .
AMA StyleAlexander Asiedu, Ryan Davis, Sandeep Kumar. Catalytic transfer hydrogenation and characterization of flash hydrolyzed microalgae into hydrocarbon fuels production (jet fuel). Fuel. 2019; 261 ():116440.
Chicago/Turabian StyleAlexander Asiedu; Ryan Davis; Sandeep Kumar. 2019. "Catalytic transfer hydrogenation and characterization of flash hydrolyzed microalgae into hydrocarbon fuels production (jet fuel)." Fuel 261, no. : 116440.
Electrochemical hydrogenation (ECH) of acetone is a relatively new method to produce isopropanol. It provides an alternative way of upgrading bio-fuels with less energy consumption and chemical waste as compared to conventional methods. In this paper, Polymer Electrolyte Membrane Fuel Cell (PEMFC) hardware was used as an electrochemical reactor to hydrogenate acetone to produce isopropanol and diisopropyl ether as a byproduct. High current efficiency (59.7%) and selectivity (>90%) were achieved, while ECH was carried out in mild conditions (65 °C and atmospheric pressure). Various operating parameters were evaluated to determine their effects on the yield of acetone and the overall efficiency of ECH. The results show that an increase in humidity increased the yield of propanol and the efficiency of ECH. The operating temperature and power supply, however, have less effect. The degradation of membranes due to contamination of PEMFC and the mitigation methods were also investigated.
Chen Li; Ashanti M. Sallee; Xiaoyu Zhang; Sandeep Kumar. Electrochemical Hydrogenation of Acetone to Produce Isopropanol Using a Polymer Electrolyte Membrane Reactor. Energies 2018, 11, 2691 .
AMA StyleChen Li, Ashanti M. Sallee, Xiaoyu Zhang, Sandeep Kumar. Electrochemical Hydrogenation of Acetone to Produce Isopropanol Using a Polymer Electrolyte Membrane Reactor. Energies. 2018; 11 (10):2691.
Chicago/Turabian StyleChen Li; Ashanti M. Sallee; Xiaoyu Zhang; Sandeep Kumar. 2018. "Electrochemical Hydrogenation of Acetone to Produce Isopropanol Using a Polymer Electrolyte Membrane Reactor." Energies 11, no. 10: 2691.
Microalgae is identified as a promising feedstock for producing renewable liquid transportation fuels; however, lipids extraction from microalgae for downstream processing to biofuels is one of the important challenges for algal based biorefineries. This work aims at evaluating the potential of applying flash hydrolysis (FH) as a chemical-free technique to increase the lipids extractability of algal biomass as well as its integration with the hydrothermal liquefaction (HTL) of microalgae to enhance the biocrude yields and characteristics for fuel production. To this aim, the FH process was performed on three different algal species (Scenedesmus sp., Nannochloropsis sp., and Chlorella vulgaris) at 280 °C and 10 s of residence time. Following FH, in addition to the nutrients rich hydrolysate, approximately, 40 wt% of solids containing almost all (>90 wt%) the lipids termed as biofuels intermediates (BI), were recovered. Kinetics study on lipids extractability from the BI and their lipid profile analyses were conducted for each algal species. The results showed that the FH process had significantly enhanced the lipids extractability. For all three algae species, lipid yields from BI were higher than that of the raw algae. Lipid yields of Chlorella vulgaris in the first 15 min were more than five times higher (52.3 ± 0.8 vs. 10.7 ± 0.9 wt%) than that of raw algae during n-hexane based solvent extraction. The kinetics of lipids extractability followed a zero-order reaction rate for all wet raw microalgae and the BI of Scenedesmus sp., while the BI recovered from the other two algal species were determined as a second-order reaction. Comparison of fatty acids profiles indicated the contribution of the FH process in saturating fatty acids. Subsequent to lipids extraction, a conventional hydrothermal liquefaction was performed at 350 °C and 1 h to compare the biocrude yields from raw versus BI of Chlorella vulgaris microalgae. The results showed that the biocrude yields from the BI and its quality was significantly enhanced post FH than that of raw algae. The FH process was proven to be a viable option for lipid extraction by increasing the extent of recovery and decreasing the extraction time. Its integration with HTL notably impact the biocrude yields and characteristics for fuel production.
Ali Teymouri; Kameron J. Adams; Tao Dong; Sandeep Kumar. Evaluation of lipid extractability after flash hydrolysis of algae. Fuel 2018, 224, 23 -31.
AMA StyleAli Teymouri, Kameron J. Adams, Tao Dong, Sandeep Kumar. Evaluation of lipid extractability after flash hydrolysis of algae. Fuel. 2018; 224 ():23-31.
Chicago/Turabian StyleAli Teymouri; Kameron J. Adams; Tao Dong; Sandeep Kumar. 2018. "Evaluation of lipid extractability after flash hydrolysis of algae." Fuel 224, no. : 23-31.
The development of algal biorefineries is strongly associated with the nutrient management, particularly phosphorus, which is a limited mineral resource. Flash hydrolysis (FH) has been widely applied to a variety of algae species to fractionate its constituents. This chemical-free, subcritical water technique was used to extract more than 80 wt % of phosphorus available in the Scenedesmus sp. as water-soluble phosphates in the aqueous phase (hydrolysate). The phosphate-rich hydrolysate was subjected to the hydrothermal mineralization (HTM) process at 280 °C and 5–90 min of residence time to mineralize phosphates as allotropes of calcium phosphate such as hydroxyapatite (HAp) and whitlockite (WH). In the current study, the effect of reaction time on phosphate mineralization from the hydrolysate as well as the composition, structure and the morphology of the precipitates were studied. Calcium hydroxide and commercial HAp were used as the mineralizer and seeding material, respectively. More than 97 wt % of phosphate and almost 94 wt % of calcium were removed in the first 5 min of the HTM process. Results revealed that as the HTM reaction time increased, calcium phosphate precipitates transformed from WH to carbonated HAp. The integration of the proposed mineralization process with FH can be a cost-effective pathway to produce sustainable, and high value phosphate-based bioproducts from algae. The application of HAp includes biomedical applications such as synthetic bone and implant filling, drug delivery, chromatography, corrosion resistance materials, catalytic activities and fertilizers.
Ali Teymouri; Ben J. Stuart; Sandeep Kumar. Effect of Reaction Time on Phosphate Mineralization from Microalgae Hydrolysate. ACS Sustainable Chemistry & Engineering 2017, 6, 618 -625.
AMA StyleAli Teymouri, Ben J. Stuart, Sandeep Kumar. Effect of Reaction Time on Phosphate Mineralization from Microalgae Hydrolysate. ACS Sustainable Chemistry & Engineering. 2017; 6 (1):618-625.
Chicago/Turabian StyleAli Teymouri; Ben J. Stuart; Sandeep Kumar. 2017. "Effect of Reaction Time on Phosphate Mineralization from Microalgae Hydrolysate." ACS Sustainable Chemistry & Engineering 6, no. 1: 618-625.
Process simulation and techno-economic analysis (TEA) of 95 wt % protein concentrate (water-soluble peptides and free amino acids) from microalgae was performed using SuperPro Designer v9.0. The analysis includes processes such as microalgae cultivation, harvesting, protein extraction, and spray drying. The subcritical water-based Flash Hydrolysis (FH) process was used in generating bench-scale continuous flow reactor experimental data on protein extraction from microalgae slurry. The TEA is conducted for a baseline capacity of 153 metric tonnes per day (MT/day) protein concentrate production requiring a throughput of 336 MT/day dry algae assuming 54 wt % protein content. Sensitivity analysis reveals the following baseline economic figures. Fixed capital investment (FCI): $286 million; annual operating cost (AOC): $146 million; annualized cost: $185 million/year at 10% discount rate for 15 yr; unit cost of production: $2.99/kg protein depending on the algae slurry density; minimum selling price: $4.31/kg protein. © 2017 American Institute of Chemical Engineers Environ Prog, 2017
Alexander Asiedu; Stuart Ben; Eleazer Resurreccion; Sandeep Kumar. Techno-economic analysis of protein concentrate produced by flash hydrolysis of microalgae. Environmental Progress & Sustainable Energy 2017, 37, 881 -890.
AMA StyleAlexander Asiedu, Stuart Ben, Eleazer Resurreccion, Sandeep Kumar. Techno-economic analysis of protein concentrate produced by flash hydrolysis of microalgae. Environmental Progress & Sustainable Energy. 2017; 37 (2):881-890.
Chicago/Turabian StyleAlexander Asiedu; Stuart Ben; Eleazer Resurreccion; Sandeep Kumar. 2017. "Techno-economic analysis of protein concentrate produced by flash hydrolysis of microalgae." Environmental Progress & Sustainable Energy 37, no. 2: 881-890.
Tobacco plants can be developed as an energy crop for biofuels production. Tobacco represents a well-established non-food crop with an over 400-year tradition of cultivation in the United States. It is the most popular non-food crop in the world, grown in more than 120 other countries. Energy tobacco as a platform biomass for biofuels, combined with a water-based green-process technology to produce fermentable sugars from tobacco plants or tobacco stalks, was the aim of this study. The composition analysis showed that non-structural sugars in modified or unmodified tobacco leaves are comparable to those of energy crops (switch grass, miscanthus), whereas lignin content in tobacco leaves is significantly lower. Moreover, the elemental analysis of tobacco leaves showed that the carbon content is in the range of 37–39 wt% on a dry basis, and oil content was about 5 wt%. Upon hydrolysis, more than 75 wt% of structural or non-structural sugars in tobacco biomass was available as glucose. The results showed that tobacco cellulose could be effectively converted to hydrolytic products (glucose, cellobiose and oligosaccharides) within a few seconds under hydrothermal liquefaction (HTL) conditions. There are some parameters that are crucial for a successful HTL reaction, such as residence time, temperature, pressure and the particle size of the biomass.
Florin G. Barla; Sandeep Kumar. Tobacco biomass as a source of advanced biofuels. Biofuels 2016, 10, 335 -346.
AMA StyleFlorin G. Barla, Sandeep Kumar. Tobacco biomass as a source of advanced biofuels. Biofuels. 2016; 10 (3):335-346.
Chicago/Turabian StyleFlorin G. Barla; Sandeep Kumar. 2016. "Tobacco biomass as a source of advanced biofuels." Biofuels 10, no. 3: 335-346.
The cost-effective production of liquid biofuels from microalgae is limited by several factors such as recovery of the lipid fractions as well as nutrients management. Flash hydrolysis, a rapid hydrothermal process, has been successfully applied to fractionate the microalgal biomass into solid biofuels intermediates while recovering a large amount of the nutrients in the aqueous phase (hydrolyzate) in a continuous flow reactor. The aim of the work is to enhance the quality of a high-ash containing marine algae Nannochloropsis gaditana as biofuel feedstock while recycling nutrients directly for algae cultivation. Characterization of products demonstrated an increase in extractable lipids from 33.5 to 65.5 wt % (dry basis) while retaining the same fatty acid methyl ester profile, in addition to diminution of more than 70 wt % of ash compared to raw microalgae. Moreover, the hydrolyzate was directly used to grow a microalga of the same genus. © 2016 American Institute of Chemical Engineers AIChE J, 2016
Ali Teymouri; Sandeep Kumar; Elena Barbera; Eleonora Sforza; Alberto Bertucco; Tomas Morosinotto. Integration of biofuels intermediates production and nutrients recycling in the processing of a marine algae. AIChE Journal 2016, 63, 1494 -1502.
AMA StyleAli Teymouri, Sandeep Kumar, Elena Barbera, Eleonora Sforza, Alberto Bertucco, Tomas Morosinotto. Integration of biofuels intermediates production and nutrients recycling in the processing of a marine algae. AIChE Journal. 2016; 63 (5):1494-1502.
Chicago/Turabian StyleAli Teymouri; Sandeep Kumar; Elena Barbera; Eleonora Sforza; Alberto Bertucco; Tomas Morosinotto. 2016. "Integration of biofuels intermediates production and nutrients recycling in the processing of a marine algae." AIChE Journal 63, no. 5: 1494-1502.
In this study, un-hydrolyzed (UHS) biomass residue generated from enzymatic hydrolysis of corn stover was used for activated carbon production. Activated carbons were prepared by high-temperature chemical activation method, with phosphoric acid and Zinc chloride (ZnCl2) as the activation agents. A factorial design was used to optimize the activation process, and five different parameters (pretreatment methods, impregnation ratio, activation time, activation temperature, and temperature increasing rate) were analyzed with respect to their influence on BET surface area and pore volume. At optimized activation condition (i.e., co-precipitation pretreatment method, impregnation ratio 1.5, activation time 60 min, activation temperature 500 °C and heating rate 60 °C/min), activated carbon is obtained with surface areas and pore volumes approaching 1117 m2/g and 0.12 cm3/g, respectively. The capacity of methylene blue adsorption from aqueous solutions could reach 279 mg/g and adsorption isotherm fits Langmuir model. Iodine number of the prepared activated carbon was comparable to that of commercially available material. The prepared activated carbon was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, thermo-gravimetric analysis (TGA), and energy-dispersive spectrometry (EDS).
Chen Li; Sandeep Kumar. Preparation of activated carbon from un-hydrolyzed biomass residue. Biomass Conversion and Biorefinery 2016, 6, 407 -419.
AMA StyleChen Li, Sandeep Kumar. Preparation of activated carbon from un-hydrolyzed biomass residue. Biomass Conversion and Biorefinery. 2016; 6 (4):407-419.
Chicago/Turabian StyleChen Li; Sandeep Kumar. 2016. "Preparation of activated carbon from un-hydrolyzed biomass residue." Biomass Conversion and Biorefinery 6, no. 4: 407-419.
Sergiy Popov; Sandeep Kumar. Rapid Hydrothermal Deoxygenation of Oleic Acid over Activated Carbon in a Continuous Flow Process. Energy & Fuels 2015, 29, 3377 -3384.
AMA StyleSergiy Popov, Sandeep Kumar. Rapid Hydrothermal Deoxygenation of Oleic Acid over Activated Carbon in a Continuous Flow Process. Energy & Fuels. 2015; 29 (5):3377-3384.
Chicago/Turabian StyleSergiy Popov; Sandeep Kumar. 2015. "Rapid Hydrothermal Deoxygenation of Oleic Acid over Activated Carbon in a Continuous Flow Process." Energy & Fuels 29, no. 5: 3377-3384.
Water under subcritical conditions in a continuous-flow reactor (flash hydrolysis) has proved to be an efficient and environmentally friendly method for hydrolyzing proteins from microalgae biomass in a very short residence time (few seconds). In this study, flash hydrolysis experiments were conducted at three different temperatures (240, 280, and 320 °C) and three residence times (6, 9, and 12 s) to understand the kinetics of the hydrolysis of algae proteins to water-soluble peptides and arginine. Laboratory-grown protein-rich Scenedesmus sp. with an average composition of 54% proteins, 17% lipids, and 23% carbohydrates was used as the feedstock. After flash hydrolysis, both liquid and solid products were collected, and the contents of soluble peptides and arginine in the liquid fraction and of remaining proteinaceous material in the solids were analyzed. For all experiments above 240 °C at all residence times, the yield of soluble peptides was in the range of 57–67% of the algae protein, whereas the maximum arginine yield (81.51%) was achieved at 320 °C and a residence time of 6 s. The protein solubilization to soluble peptides fitted second-order reaction kinetics, whereas for arginine, the process was zeroth-order; the activation energies were calculated to be 43.0 and 34.1 kJ/mol, respectively. The results of this study suggest that flash hydrolysis can be an environmentally benign method for hydrolyzing proteins from microalgae to produce valuable coproducts such as arginine as a free amino acid and water-soluble peptides along with lipid-rich solids (biofuel intermediate) as a feedstock for biofuel production.
Jose L. Garcia-Moscoso; Ali Teymouri; Sandeep Kumar. Kinetics of Peptides and Arginine Production from Microalgae (Scenedesmus sp.) by Flash Hydrolysis. Industrial & Engineering Chemistry Research 2015, 54, 2048 -2058.
AMA StyleJose L. Garcia-Moscoso, Ali Teymouri, Sandeep Kumar. Kinetics of Peptides and Arginine Production from Microalgae (Scenedesmus sp.) by Flash Hydrolysis. Industrial & Engineering Chemistry Research. 2015; 54 (7):2048-2058.
Chicago/Turabian StyleJose L. Garcia-Moscoso; Ali Teymouri; Sandeep Kumar. 2015. "Kinetics of Peptides and Arginine Production from Microalgae (Scenedesmus sp.) by Flash Hydrolysis." Industrial & Engineering Chemistry Research 54, no. 7: 2048-2058.
It is widely believed that the biofuels can be sustainably produced using microalgae that are known to convert CO2 from the atmosphere to lipids, in the presence of nutrient and accumulate them as their body mass. However, when algal biofuels are produced using thermochemical route, ~30–65 % of proteins present in algae are lost due to decomposition and some of the nitrogen from amino acids is incorporated into the biofuels. The algal protein is a valuable resource that can bring additional revenue to the biorefinery by converting this co-product to high-value polyurethanes. In this work, we have demonstrated a one-step removal of proteins from algae through hydrolysis of the proteins to smaller peptides and amino acids using environment friendly flash hydrolysis (FH) process. Subcritical water was used as a reactant and as a reaction media for hydrolyzing the algae proteins via FH. Scenedesmus spp., slurry in water (3.8 %), was used as the algal feed stock during the FH process which was run at 280 °C for a residence time of 10 s. The soluble amino acids and peptides were separated from the other insoluble algal biomass components (cell wall and lipids) by filtration followed by freeze-drying. The product was then characterized by ion chromatography and Fourier transform ion cyclotron resonance mass spectrometry to determine its composition. The freeze-dried peptide and amino acids were then reacted with diamine and ethylene carbonate to produce polyols that were further processed to produce polyurethane. The relatively high hydroxyl value of these amino acid-based polyols and their compatibility with other commercially available polyols made them particularly suitable for producing rigid polyurethane foams. Due to the presence of amines and secondary amines in these polyols, the polymerization process was self-catalytic and the resulting foams are less flammable than conventional rigid polyurethane foams. The conversion of algal proteins to high-value industrial products by a relatively simple process greatly improves the value of proteins extracted from algae.
Sandeep Kumar; Elodie Hablot; Jose Luis Garcia Moscoso; Wassim Obeid; Patrick G. Hatcher; Brandon Michael Duquette; Daniel Graiver; Ramani Narayan; Venkatesh Balan. Polyurethanes preparation using proteins obtained from microalgae. Journal of Materials Science 2014, 49, 7824 -7833.
AMA StyleSandeep Kumar, Elodie Hablot, Jose Luis Garcia Moscoso, Wassim Obeid, Patrick G. Hatcher, Brandon Michael Duquette, Daniel Graiver, Ramani Narayan, Venkatesh Balan. Polyurethanes preparation using proteins obtained from microalgae. Journal of Materials Science. 2014; 49 (22):7824-7833.
Chicago/Turabian StyleSandeep Kumar; Elodie Hablot; Jose Luis Garcia Moscoso; Wassim Obeid; Patrick G. Hatcher; Brandon Michael Duquette; Daniel Graiver; Ramani Narayan; Venkatesh Balan. 2014. "Polyurethanes preparation using proteins obtained from microalgae." Journal of Materials Science 49, no. 22: 7824-7833.
Among the several biomass resources available, microalgae have the potential to produce more biofuels per acre than any other source without competing with food and feed production. One of the major challenges in utilization of microalgae is its high water content, high nitrogen (protein) content, and variable biochemical composition. The conventional thermochemical conversion processes such as pyrolysis and gasification require dry biomass for production of biofuels. Sub- and supercritical water (critical point: 374 °C, 22.1 MPa) technology, which can utilize wet biomass, capitalizes on the extraordinary solvent properties of water at elevated temperature for converting microalgae to high-energy density biofuels. Here, water acts as reactant as well as reaction medium in performing hydrolysis, depolymerization, dehydration, decarboxylation, and many other chemical reactions. Subcritical water can be used as green solvent to extract valuable bioproducts from microalgae. Further, sub- and supercritical water technology can be used for liquefaction of microalgae to produce liquid biofuels and for gasification to produce gaseous fuels such as methane, syngas, and hydrogen. In sub- and supercritical water-based processes, water is kept in liquid or supercritical phase by applying pressure greater than the vapor pressure of water. Thus, latent heat required for phase change of water is avoided. The chapter explains the theory of sub- and supercritical water-based processes for biofuels applications and the present state of the technology.
Sandeep Kumar. Sub- and Supercritical Water-Based Processes for Microalgae to Biofuels. Cellular Origin, Life in Extreme Habitats and Astrobiology 2012, 467 -493.
AMA StyleSandeep Kumar. Sub- and Supercritical Water-Based Processes for Microalgae to Biofuels. Cellular Origin, Life in Extreme Habitats and Astrobiology. 2012; ():467-493.
Chicago/Turabian StyleSandeep Kumar. 2012. "Sub- and Supercritical Water-Based Processes for Microalgae to Biofuels." Cellular Origin, Life in Extreme Habitats and Astrobiology , no. : 467-493.
Biochar produced from switchgrass via hydrothermal carbonization (HTC) was used as a sorbent for the removal of copper and cadmium from aqueous solution. The cold activation process using KOH at room temperature was developed to enhance the porous structure and sorption properties of the HTC biochar. The sorption efficiency of HTC biochar and alkali activated HTC biochar (HTCB) for removing copper and cadmium from aqueous solution were compared with commercially available powdered activated carbon (PAC). The present batch adsorption study describes the effects of solution pH, biochar dose, and contact time on copper and cadmium removal efficiency from single metal ion aqueous solutions. The activated HTCB exhibited a higher adsorption potential for copper and cadmium than HTC biochar and PAC. Experiments conducted with an initial metal concentration of 40 mg/L at pH 5.0 and contact time of 24 h resulted in close to 100% copper and cadmium removal by activated HTCB at 2 g/L, far greater than what was observed for HTC biochar (16% and 5.6%) and PAC (4% and 7.7%). The adsorption capacities of activated HTCB for cadmium removal were 34 mg/g (0.313 mmol/g) and copper removal was 31 mg/g (0.503 mmol/g).
Pusker Regmi; Jose Luis Garcia Moscoso; Sandeep Kumar; Xiaoyan Cao; Jingdong Mao; Gary Schafran. Removal of copper and cadmium from aqueous solution using switchgrass biochar produced via hydrothermal carbonization process. Journal of Environmental Management 2012, 109, 61 -69.
AMA StylePusker Regmi, Jose Luis Garcia Moscoso, Sandeep Kumar, Xiaoyan Cao, Jingdong Mao, Gary Schafran. Removal of copper and cadmium from aqueous solution using switchgrass biochar produced via hydrothermal carbonization process. Journal of Environmental Management. 2012; 109 ():61-69.
Chicago/Turabian StylePusker Regmi; Jose Luis Garcia Moscoso; Sandeep Kumar; Xiaoyan Cao; Jingdong Mao; Gary Schafran. 2012. "Removal of copper and cadmium from aqueous solution using switchgrass biochar produced via hydrothermal carbonization process." Journal of Environmental Management 109, no. : 61-69.
One of the major challenges in utilization of biomass is its high moisture content and variable composition. The conventional thermochemical conversion processes such as pyrolysis and gasification require dry biomass for production of biofuels. Sub- and supercritical water (critical point: 374°C, 22.1°MPa) technology, which can utilize wet biomass, capitalizes on the extraordinary solvent properties of water at elevated temperature for converting biomass to high energy density fuels and functional carbonaceous materials. Here, water acts as reactant as well as reaction medium in performing hydrolysis, depolymerization, dehydration, decarboxylation, and many other chemical reactions. One of the advantages is that the large parasitic energy losses that can consume much of the energy content of the biomass for moisture removal are avoided. In sub- and supercritical water-based processes, water is kept in liquid or supercritical phase by applying pressure greater than the vapor pressure of water. Thus, latent heat required for phase change of water from liquid to vapor phase (2.26 MJ/kg of water) is not needed. For a typical 250°C subcritical water process, the energy requirement to heat water from ambient condition to the reaction temperature is about 1 MJ/kg, equivalent to 6–8% of energy content of dry biomass.
Sandeep Kumar. Sub- and Supercritical Water Technology for Biofuels. Advanced Biofuels and Bioproducts 2012, 147 -183.
AMA StyleSandeep Kumar. Sub- and Supercritical Water Technology for Biofuels. Advanced Biofuels and Bioproducts. 2012; ():147-183.
Chicago/Turabian StyleSandeep Kumar. 2012. "Sub- and Supercritical Water Technology for Biofuels." Advanced Biofuels and Bioproducts , no. : 147-183.