Ponnuswamy Vijayaraghavan

Biotronik (India)

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Samuel Gnana Prakash Vincent

Manonmaniam Sundaranar University

Mariadhas Valan Arasu

King Saud University

Naif Abdullah Al‐Dhabi

King Saud University

Mohamed S. Elshikh

King Saud University

Conrad J. Kulik

Electric Power Research Institute

Ki Choon Choi

National Institute of Animal Science

Jayarajapazham Rajaselvam

Manonmaniam Sundaranar University

Mohammed A. Almalki

King Faisal University

Young Ock Kim

Soonchunhyang University

Rengasamy Sathya

PRIST University

Cooperative Institutions

King Saud University

Manonmaniam Sundaranar University

Karpagam Academy of Higher Education

Riyadh Elm University

Rural Development Administration

National Institute of Animal Science

Saveetha University

Soonchunhyang University

University of Akron

Stony Brook University

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Evaluation of Nanosized Iron in Slurry-Phase Fischer−Tropsch Synthesis

Energy & Fuels (2003)

Devinder Mahajan Philipp Gütlich Jürgen Ensling K. I. Pandya Ulrich Stumm

The Fischer−Tropsch (F−T) activity of three α-Fe2O3-based materials, two unsupported nanosized, NANOCAT (3 nm) and BASF (20−80 nm), and a supported micrometer-sized (32.5 μm) UCI, were measured with respect to total hydrocarbon production from synthesis gas (H2/CO ∼ 2/1). All three oxides were initially reduced under CO at 553 K in ethylflopolyolefin-164 solvent, and the extent of their reduction was established by monitoring CO2 evolution. The ease of reduction of α-Fe2O3 followed the order: UCI > NANOCAT > BASF. The Fischer−Tropsch (F−T) synthesis activities of the three reduced materials were measured at 513 K. Mössbauer and X-ray absorption fine structure (XAFS) measurements established that the initial oxides were in the α-Fe2O3 phase. Room-temperature XAFS together with low-temperature Mössbauer data of the quenched catalyst samples after 120 h F−T reaction suggest that all three catalysts were essentially a mixture of oxides and carbides with magnetite being the dominant phase. The observed high activity with NANOCAT and the presence of mainly (88%) magnetite phase indicate that either the oxide phase contributes as a catalyst or the minor (12%) carbide phase is extremely active for F−T synthesis. TEM images of the quenched samples remarkably showed that both unsupported nano materials, NANOCAT and BASF, avoided expected agglomeration and the micrometer-sized UCI converted into a nano material of <10 nm under F−T reaction conditions. The narrow particle size distribution of the quenched catalysts in the nano range (∼10−50 nm) explains the very similar activities observed with the three different-sized starting materials in the order: BASF > NANOCAT ∼ UCI. The data suggest a crucial role of nanosized Fe during F−T synthesis.

Fischer–Tropsch process

Micrometer

10.1021/ef0300343

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Citations (35)

A SINGLE-STAGE, LIQUID-PHASE DIMETHYL ETHER SYNTHESIS PROCESS FROM SYNGAS IV. THE WODYNAMIC ANALYSIS OF THE LPDME PROCESS SYSTEM

Fuel Science and Technology International (1992)

Makarand R. Gogate Ponnuswamy Vijayaraghavan Sunggyu Lee Conrad J. Kulik

Abstract In the LPDME process, methanol synthesis catalyst (composed of CuO, ZnO, and Al2O3) and the methanol dehydration catalyst (gamma-alumina) are slurried in the inert liquid phase. The catalysts constitute the solid phase. Syngas components (H2, CO, CO2, and CH4) and the products (CH3OH, H2O, and DME) constitute the vapor phase. At least three chemical reactions, viz., methanol synthesis, water-gas shift, and methanol dehydration also occur simultaneously in the liquid phase. The multicomponent phase equilibrium and the simultaneous chemical reaction equilibrium for this process system have been studied. The thermodynamic analysis has been presented in terms of the equilibrium conversions for H2and CO, syngas, and the concentration driving forces for H2 and CO. Methanol synthesis alone and co-production of methanol and DME are compared. The effects of water and CO2addition to the feed syngas on the equilibrium conversions are also investigated.

Dimethyl ether

Methanol reformer

Chemical equilibrium

Inert

Inert gas

Synthetic fuel

10.1080/08843759208915991

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Citations (13)

Thermodynamic analysis of syngas conversion chemistry

Ponnuswamy Vijayaraghavan S. Lee

The liquid phase catalytic conversion of syngas to methanol (LPMeOH{trademark}), and syngas to methanol and dimethyl ether (LPDME process) was investigated in a three-phase mini-pilot plant version of a mechanically agitated slurry reactor system. In this reactor system, the catalyst particles in powder form are slurried in the oil phase and this slurry is agitated by a mechanically driven impeller. Syngas reacts in the presence of the methanol synthesis catalyst (Cu/ZnO/Al{sub 2}O{sub 3})-oil slurry to form the product methanol in the LPMeOH process. The productivity of methanol in this process, is adversely affected by the chemical equilibrium limitation. Hence the dual catalytic approach (LPDME process), where the productivity of methanol is enhanced by the co-production of dimethyl ether with methanol, was developed to alleviate the chemical equilibrium limitation. In this LPDME process, syngas reacts in the presence of the methanol synthesis catalyst and the methanol dehydration catalyst ({gamma}-alumina), which are both slurried in the oil phase. The thermodynamics of the liquid phase methanol synthesis process and the liquid phase dimethyl ether process were investigated. The equilibrium conversions of H{sub 2}, CO, and syngas in both the processes are compared for nominally identical operating conditions. The effect of water and CO{submore » 2} addition to the feed syngas, and the effect of temperature and pressure on the LPMeOH process and the LPDME process were also compared.« less

Dimethyl ether

Methanol reformer

Synthetic fuel

Source

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Citations (0)

De-hairing protease production by an isolated Bacillus cereus strain AT under solid-state fermentation using cow dung: Biosynthesis and properties

Saudi Journal of Biological Sciences (2013)

Ponnuswamy Vijayaraghavan Sophia Lazarus Samuel Gnana Prakash Vincent

Agro-industrial residues and cow dung were used as the substrate for the production of alkaline protease by Bacillus cereus strain AT. The bacterial strain Bacillus cereus strain AT produced a high level of protease using cow dung substrate (4813 ± 62 U g(-1)). Physiological fermentation factors such as the incubation time (72 h), the pH (9), the moisture content (120%), and the inoculum level (6%) played a vital role in the enzyme bioprocess. The enzyme production improved with the supplementation of maltose and yeast extract as carbon and nitrogen sources, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and zymogram analysis of the purified protease indicated an estimated molecular mass of 46 kDa. The protease enzyme was stable over a temperature range of 40-50 °C and pH 6-9, with maximum activity at 50 °C and pH 8. Among the divalent ions tested, Ca(2+), Na(+) and Mg(2+) showed activities of 107 ± 0.7%, 103.5 ± 1.3%, and 104.6 ± 0.9, respectively. The enzyme showed stability in the presence of surfactants such as sodium dodecyl sulfate and on various commercially available detergents. The crude enzyme effectively de-haired goat hides within 18 h of incubation at 30 °C. The enzymatic properties of this protease suggest its suitable application as an additive in detergent formulation and also in leather processing. Based on the laboratory results, the use of cow dung for producing and extracting enzyme is not cumbersome and is easy to scale up. Considering its cheap cost and availability, cow dung is an ideal substrate for enzyme bioprocess in an industrial point of view.

Solid-State Fermentation

Yeast extract

10.1016/j.sjbs.2013.04.010

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Citations (94)

Probiotic and Antioxidant Potential of Lactobacillus reuteriLR12 and Lactobacillus lactisLL10 Isolated from Pineapple Puree and Quality Analysis of Pineapple-Flavored Goat Milk Yoghurt during Storage

Microorganisms (2020)

Naif Abdullah Al‐Dhabi Mariadhas Valan Arasu Ponnuswamy Vijayaraghavan Galal Ali Esmail Veeramuthu Duraipandiyan

In recent years, studies have focused on the therapeutic properties of probiotics to eliminate pathogenic microorganisms associated with various diseases. Lactobacilli are important probiotics groups that have been found to possess many health-promoting activities. This study was carried out to isolate LactobacillusreuteriLR12 and L. lactisLL10 from pineapple puree. The invitro analysis to evaluate probiotic characteristics of the isolated bacteria included survival in bile and acid tolerance. The cell-free supernatant of L. reuteri LR12 was effective against various pathogenic bacteria and fungi compared with L. lactisLL10. These two bacterial strains have strong anti-biofilm activity (100%) against Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus. The bacterial strains exhibited adhesion properties to HT-29 cells (human colorectal adenocarcinoma). These bacteria showed DPPH- (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free radical scavenging activity, scavenging of hydroxyl radical activity, superoxide radical scavenging activity, and reducing power activity in the range of 72% ± 3%to 89.3% ± 1.7%, 64% ± 2.7%to 66.8% ± 1.5%, 59.8% ± 4.1% to 63.8% ± 2.1%, and 60.4% ± 1.8%to 66.1% ± 3.3%, respectively. Pineapple puree was used as the starter culture with milk for 2 days for yogurt preparation. Pineapple puree increased flavor and showed the physicochemical properties of yogurt. The finding of the sensory evaluation revealed no significant change compared with the control, except the appearance of yogurt. These findings show that Lactobacilli and pineapple puree have potential use in various probiotic preparations for the fermentation industry.

Enterococcus faecalis

Pathogenic bacteria

Lactobacillus fermentum

Lactobacillus reuteri

10.3390/microorganisms8101461

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Citations (69)

In-vitro antidepressant property of methanol extract of Bacopa monnieri

Journal of King Saud University - Science (2022)

Jawaher Alkahtani Mohamed S. Elshikh Yheni Dwiningsih M. A. Rathi Rengasamy Sathya

Tail suspension test

Bacopa monnieri

Phytochemical

10.1016/j.jksus.2022.102299

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Citations (14)

IN-SITU ACTIVATION OF METHANOL SYNTHESIS CATALYST IN A THREE-PHASE SLURRY REACTOR

Fuel Science and Technology International (1996)

Ponnuswamy Vijayaraghavan Sunggyu Lee

ABSTRACT In the liquid phase methanol synthesis process, syngas reacts in the presence.of fine catalyst particles slurried in the oil phase, in a three phase slurry reactor system. A method for activating high concentration ( ⩽25 wt. %) of the CuO-ZnO-Al2O3 catalyst in the catalyst-oil slurry has been successfully developed. This catalyst activation process can be of crucial significance in the research and development of the methanol synthesis process in a liquid entrained reactor. The reducing gas contains 2% hydrogen in nitrogen mixture and this activation procedure is carried out at a pressure of 125 psi. The catalyst-oil slurry is subjected to a controlled temperature ramping from 110° to 250° C. The catalyst has beemshown to be effectively reduced after following this activation procedure, that is valid especially for high catalyst loadings in slurry. Since the reduction is carried out in the process liquid medium and inside the reactor system, the catalyst-oil slurry after the treatment is ready for the synthesis of methanol.

10.1080/08843759608947608

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Citations (1)

Novel Sequential Screening and Enhanced Production of Fibrinolytic Enzyme byBacillussp. IND12 Using Response Surface Methodology in Solid-State Fermentation

BioMed Research International (2017)

Ponnuswamy Vijayaraghavan Priya Rajendran Samuel Gnana Prakash Vincent Arun Arumugaperumal Naif Abdullah Al‐Dhabi

Fibrinolytic enzymes have wide applications in clinical and waste treatment. Bacterial isolates were screened for fibrinolytic enzyme producing ability by skimmed milk agar plate using bromocresol green dye, fibrin plate method, zymography analysis, and goat blood clot lysis. After these sequential screenings, Bacillus sp. IND12 was selected for fibrinolytic enzyme production. Bacillus sp. IND12 effectively used cow dung for its growth and enzyme production (687 ± 6.5 U/g substrate). Further, the optimum bioprocess parameters were found out for maximum fibrinolytic enzyme production using cow dung as a low cost substrate under solid-state fermentation. Two-level full-factorial experiments revealed that moisture, pH, sucrose, peptone, and MgSO4 were the vital parameters with statistical significance (p < 0.001). Three factors (moisture, sucrose, and MgSO4) were further studied through experiments of central composite rotational design and response surface methodology. Enzyme production of optimized medium showed 4143 ± 12.31 U/g material, which was more than fourfold the initial enzyme production (978 ± 36.4 U/g). The analysis of variance showed that the developed response surface model was highly significant (p < 0.001). The fibrinolytic enzyme digested goat blood clot (100%), chicken skin (83 ± 3.6%), egg white (100%), and bovine serum albumin (29 ± 4.9%).

Solid-State Fermentation

10.1155/2017/3909657

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Citations (29)

LIQUID PHASE METHANOL SYNTHESIS IN AN ENTRAINED REACTOR—DEVELOPMENT OF A GAS-LIQUID MASS TRANSFER CORRELATION

Fuel Science and Technology International (1995)

Ponnuswamy Vijayaraghavan Sunggyu Lee

Abstract Research on various aspects of the methanol synthesis was performed in a liquid entrained reactor. The catalyst-oil slurry is pumped through the tubular entrained reactor and syngas is fed cocurrently with the upward flow of slurry. The effect of different operating conditions, syngas composition and catalyst loadings on the productivity of methanol, was studied. The data obtained from the experiments at high catalyst loadings in slurry, was used to develop a gas-liquid mass transfer correlation for the liquid phase methanol synthesis in an entrained reactor. The productivity of methanol in an entrained reactor was then predicted using the developed mass transfer correlation. This predictive model also helps in the design, development, scale-up and commercialization of the liquid phase methanol synthesis process in an entrained reactor.

Mass transfer coefficient

Bubble column reactor

10.1080/08843759508947682

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Citations (1)

Enhanced production antibiotics using green gram husk medium by Streptomyces sp. SD1 using response surface methodology

Journal of King Saud University - Science (2020)

M. Kalaiyarasi Parvaiz Ahmad Ponnuswamy Vijayaraghavan

Discovery of various antibiotics from the genus Streptomyces attained good attention from Industrialists and Pharmacologists. Streptomyces sp. produce various antibiotics to treat various diseases. The ability of Streptomyces sp. SD1 to synthesize antibiotics using various agro industrial wastes as solid substrate was evaluated. The agro wastes used were pineapple peel, wheat bran, apple pomace, rice bran, tapioca powder, orange peel and green gram husk for the production of antibiotics. The culture medium was optimized by using various carbon, nitrogen, ions, and minerals. To enhance maximum metabolite production, fermentation of Streptomyces sp. SD1 was optimized through response surface methodology. RSM is also used to analyze the interactions among the factors and screening the culture medium components. Streptomyces sp. SD1 had the ability to produce antibiotics at highest level with green gram husk as the substrate. Among the carbon sources, starch, and maltose enhanced the production of antibiotics. However, the selected sources such as, sucrose and glucose negatively influenced on antibiotics production. Beef extract, peptone and yeast extract positively influenced on antibiotics production. However, addition of casein and oat meal inhibited the production of antibiotics. Among the divalent ions, calcium chloride, magnesium sulphate and manganese chloride enhanced the production of antibiotics, however supplementation of cobalt chloride and mercuric chloride affected antibiotics production. All selected mineral sources enhanced the production of antibiotics and the yield was higher than control. 3D response surface graphs showed maximum yield of antibiotics at higher concentration of selected nutrient sources. Antibiotics production enhanced 2.9 fold by Streptomyces sp. SD1 in optimized medium than unoptimized medium. Among the isolates, Streptomyces sp. SD1 showed high antimicrobial activity. The selected actinomycetes utilized green gram husk for antibiotics production. Also addition of nutrient sources stimulated the production of antibiotics. Green gram husk is highly useful for the production of antibiotics in large scale.

Yeast extract

Husk

10.1016/j.jksus.2020.02.014

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Citations (27)