Abstract: This paper describes technological possibilities to
enhance methane productionin the anaerobic stabilization of wastewater treatment plant excess sludge. This objective can be achieved by the addition of waste residues: crude glycerol from biodiesel production and residues from fishery. The addition
ofglycerol in an amount by weight of 2 – 5% causes enhancement of methane production of about 250 – 400%. At the same time the
percentage increase of total solids concentration in the outgoing sludge is ten or more times less. The containment of methane in
biogas is higher in case of admixed substrate.
Abstract: As it is known, buoyancy and drag forces rule bubble's rise velocity in a liquid column. These forces are strongly dependent on fluid properties, gravity as well as equivalent's diameter. This study reports a set of bubble rising velocity experiments in a liquid column using water or glycerol. Several records of terminal velocity were obtained. The results show that bubble's rise terminal velocity is strongly dependent on dynamic viscosity effect. The data set allowed to have some terminal velocities data interval of 8.0 ? 32.9 cm/s with Reynolds number interval 1.3 -7490. The bubble's movement was recorded with a video camera. The main goal is to present an original set data and results that will be discussed based on two-phase flow's theory. It will also discussed, the prediction of terminal velocity of a single bubble in liquid, as well as the range of its applicability. In conclusion, this study presents general expressions for the determination of the terminal velocity of isolated gas bubbles of a Reynolds number range, when the fluid proprieties are known.
Abstract: The catalytic dehydroxylation of glycerol to propylene
glycol was investigated over Cu-ZnO/Al2O3 prepared by incipient
wetness impregnation (IWI) method with different purity feedstocks -
refined glycerol and technical grade glycerol. The main purpose is to
investigate the effects of feed impurities that cause the catalyst
deactivation. The prepared catalyst were tested for its catalytic
activity and selectivity in a continuous flow fixed bed reactor at 523
K, 500 psig, H2/feed molar ratio of 4 and WHSV of 3 h-1. The results
showed that conversion of refined glycerol and technical grade
glycerol at time on stream 6 hour are 99% and 71% and selectivity to
propylene glycol are 87% and 56% respectively. The ICP-EOS and
TPO results indicated that the cause of catalyst deactivation was the
amount of impurities in the feedstock. The higher amount of
impurities (especially Na and K) the lower catalytic activity.
Abstract: In this study, a synthetic pathway was created by
assembling genes from Clostridium butyricum and Escherichia coli
in different combinations. Among the genes were dhaB1 and dhaB2
from C. butyricum VPI1718 coding for glycerol dehydratase (GDHt)
and its activator (GDHtAc), respectively, involved in the conversion
of glycerol to 3-hydroxypropionaldehyde (3-HPA). The yqhD gene
from E.coli BL21 was also included which codes for an NADPHdependent
1,3-propanediol oxidoreductase isoenzyme (PDORI)
reducing 3-HPA to 1,3-propanediol (1,3-PD). Molecular modeling
analysis indicated that the conformation of fusion protein of YQHD
and DHAB1 was favorable for direct molecular channeling of the
intermediate 3-HPA. According to the simulation results, the yqhD
and dhaB1 gene were assembled in the upstream of dhaB2 to express
a fusion protein, yielding the recombinant strain E. coliBL21
(DE3)//pET22b+::yqhD-dhaB1_dhaB2 (strain BP41Y3). Strain
BP41Y3 gave 10-fold higher 1,3-PD concentration than E. coliBL21
(DE3)//pET22b+::yqhD-dhaB1_dhaB2 (strain BP31Y2) expressing
the recombinant enzymes simultaneously but in a non-fusion mode.
This is the first report using a gene fusion approach to enhance the
biological conversion of glycerol to the value added compound 1,3-
PD.
Abstract: Transesterification of candlenut (aleurites moluccana)
oil with methanol using potassium hydroxide as catalyst was
studied. The objective of the present investigation was to produce
the methyl ester for use as biodiesel. The operation variables
employed were methanol to oil molar ratio (3:1 – 9:1), catalyst
concentration (0.50 – 1.5 %) and temperature (303 – 343K). Oil
volume of 150 mL, reaction time of 75 min were fixed as common
parameters in all the experiments. The concentration of methyl ester
was evaluated by mass balance of free glycerol formed which was
analyzed by using periodic acid. The optimal triglyceride conversion
was attained by using methanol to oil ratio of 6:1, potassium
hydroxide as catalyst was of 1%, at room temperature. Methyl ester
formed was characterized by its density, viscosity, cloud and pour
points. The biodiesel properties had properties similar to those of
diesel oil, except for the viscosity that was higher.
Abstract: Pretreatment of lignocellulosic biomass materials from
poplar, acacia, oak, and fir with different ionic liquids (ILs)
containing 1-alkyl-3-methyl-imidazolium cations and various anions
has been carried out. The dissolved cellulose from biomass was
precipitated by adding anti-solvents into the solution and vigorous
stirring. Commercial cellulases Celluclast 1.5L and Accelerase 1000
have been used for hydrolysis of untreated and pretreated
lignocellulosic biomass. Among the tested ILs, [Emim]COOCH3
showed the best efficiency, resulting in highest amount of liberated
reducing sugars. Pretreatment of lignocellulosic biomass using
glycerol-ionic liquids combined pretreatment and dilute acid-ionic
liquids combined pretreatment were evaluated and compared with
glycerol pretreatment, ionic liquids pretreatment and dilute acid
pretreatment.
Abstract: The fluorescent pseudomonad strain R81 is a root
colonizing rhizobacteria which promotes the growth of many plants
by various mechanisms. Its broth containing siderophore (ironchelating
compound) and 2,4- diacetyl phloroglucinol (DAPG) is
used for preparing bioinoculant formulations for agronomical
applications. Glycerol was found to be the best carbon source for
improved biomass production. Splitting of nitrogen source to NH4Cl
and urea had a stabilizing effect on pH during batch cultivation. Ltryptophan
at 0.5 % in the medium increased the siderophore
production to 850 mg/l. During batch cultivation of the strain in a
bioreactor, a maximum of 4 g/l of dry cell mass, 1.8 g/l of
siderophore and 20 mg/l of DAPG was achieved when glycerol was
15 g/l and C/N ratio was maintained at 12.5. In case of intermittent
feeding of fresh medium during fed-batch cultivation, the dry cell
mass was increased to 25 g/l with improved production of DAPG to
70 mg/l.
Abstract: In the present work homogeneous silica film on
silicon was fabricated by colloidal silica sol. The silica sol precursor
with uniformly granular particle was derived by the alkaline
hydrolysis of tetraethoxyorthosilicate (TEOS) in presence of glycerol
template. The film was prepared by dip coating process. The
templated hetero-structured silica film was annealed at elevated
temperatures to generate nano- and meso porosity in the film. The
film was subsequently annealed at different temperatures to make it
defect free and abrasion resistant. The sol and the film were
characterized by the measurement of particle size distribution,
scanning electron microscopy, XRD, FTIR spectroscopy,
transmission electron microscopy, atomic force microscopy,
measurement of the refractive index, thermal conductivity and
abrasion resistance. The porosity of the films decreased whereas
refractive index and dielectric constant of it `increased with the
increase in the annealing temperature. The thermal conductivity of
the films increased with the increase in the film thickness. The
developed porous silica film holds strong potential for use in
different areas.
Abstract: Polyurethanes (PURs) are very versatile polymeric
materials with a wide range of physical and chemical properties.
PURs have desirable properties such as high abrasion resistance, tear
strength, shock absorption, flexibility and elasticity. Although they
have relatively poor thermal stability, this can be improved by using
treated clay. Polyurethane/clay nanocomposites have been
synthesized from renewable sources. A polyol for the production of
polyurethane by reaction with an isocyanate was obtained by the
synthesis of palm oil-based oleic acid with glycerol. Dodecylbenzene
sulfonic acid (DBSA) was used as catalyst and emulsifier. The
unmodified clay (kunipia-F) was treated with cetyltrimethyl
ammonium bromide (CTAB-mont) and octadodecylamine (ODAmont).
The d-spacing in CTAB-mont and ODA-mont were 1.571 nm
and 1.798 nm respectively and larger than that of the pure-mont
(1.142 nm). The organoclay was completely intercalated in the
polyurethane, as confirmed by a wide angle x-ray diffraction
(WAXD) pattern.
The results showed that adding clay demonstrated better thermal
stability in comparison with the virgin polyurethane. Onset
degradation of pure PU is at 200oC, and is lower than that of the
CTAB-mont PU and ODA-mont PU which takes place at about
318oC and 330oC, respectively. The mechanical properties (including
the dynamic mechanical properties) of pure polyurethane (PU) and
PU/clay nanocomposites, were measured. The modified organoclay
had a remarkably beneficial effect on the strength and elongation at
break of the nanocomposites, which both increased with increasing
clay content with the increase of the tensile strength of more than
214% and 267% by the addition of only 5 wt% of the
montmorillonite CTAB-mont PU and ODA-mont PU, respectively.
Abstract: Cardiovascular diseases, principally atherosclerosis, are responsible for 30% of world deaths. Atherosclerosis is due to the formation of plaque. The fatty plaque may be at risk of rupture, leading typically to stroke and heart attack. The plaque is usually associated with a high degree of lumen reduction, called a stenosis.It is increasingly recognized that the initiation and progression of disease and the occurrence of clinical events is a complex interplay between the local biomechanical environment and the local vascular biology. The aim of this study is to investigate the flow behavior through a stenosed artery. A physical experiment was performed using an artery model and blood analogue fluid. An axisymmetric model constructed consists of contraction and expansion region that follow a mathematical form of cosine function. A 30% diameter reduction was used in this study. The flow field was measured using particle image velocimetry (PIV). Spherical particles with 20μm diameter were seeded in a water-glycerol-NaCl mixture. Steady flow Reynolds numbers are 250. The area of interest is the region after the stenosis where the flow separation occurs. The velocity field was measured and the velocity gradient was investigated. There was high particle concentration in the recirculation zone. High velocity gradient formed immediately after the stenosis throat created a lift force that enhanced particle migration to the flow separation area.
Abstract: The subcellular organelles called oil bodies (OBs) are lipid-filled quasi-spherical droplets produced from the endoplasmic reticulum (ER) and then released into the cytoplasm during seed development. It is believed that an OB grows by coalescence with other OBs and that its stability depends on the composition of oleosins, major proteins inserted in the hemi membrane that covers OBs. In this study, we measured the OB-volume distribution from different genotypes of A. thaliana after 7, 8, 9, 10 and 11 days of seed development. In order to test the hypothesis of OBs dynamics, we developed a simple mathematical model using non-linear differential equations inspired from the theory of coagulation. The model describes the evolution of OB-volume distribution during the first steps of seed development by taking into consideration the production of OBs, the increase of triacylglycerol volume to be stored, and the growth by coalescence of OBs. Fitted parameters values show an increase in the OB production and coalescence rates in A. thaliana oleosin mutants compared to wild type.
Abstract: Chemical detection is still a continuous challenge when
it comes to designing single-walled carbon nanotube (SWCNT)
sensors with high selectivity, especially in complex chemical
environments. A perfect example of such an environment would be in
thermally oxidized soybean oil. At elevated temperatures, oil oxidizes
through a series of chemical reactions which results in the formation of
monoacylglycerols, diacylglycerols, oxidized triacylglycerols, dimers,
trimers, polymers, free fatty acids, ketones, aldehydes, alcohols,
esters, and other minor products. In order to detect the rancidity of
oxidized soybean oil, carbon nanotube chemiresistor sensors have
been coated with polyethylenimine (PEI) to enhance the sensitivity
and selectivity. PEI functionalized SWCNTs are known to have a high
selectivity towards strong electron withdrawing molecules. The
sensors were very responsive to different oil oxidation levels and
furthermore, displayed a rapid recovery in ambient air without the
need of heating or UV exposure.
Abstract: Yam starch obtained from the water yam (munlued)
by the wet milling process was studied for some physicochemical
properties. Yam starch film was prepared by casting using glycerol as
a plasticizer. The effect of different glycerol (1.30, 1.65 and
2.00g/100g of filmogenic solution) and starch concentrations (3.30,
3.65 and 4.00g /100g of filmogenic solution) were evaluated on some
characteristics of the film. The temperature for obtaining the
gelatinized starch solution was 70-80°C and then dried at 45°C for 4
hours. The resulting starch from munlued granular morphology was
triangular and the average size of the granule was 26.68 μm. The
amylose content by colorimetric method was 26 % and the gelatinize
temperature was 70-80°C. The appearance of the film was smooth,
transparent, and glossy with average moisture content of 25.96% and
thickness of 0.01mm. Puncture deformation and flexibility increased
with glycerol content. The starch and glycerol concentration were a
significant factor of the yam starch film characteristics. Yam starch
film can be described as a biofilm providing many applications and
developments with the advantage of biodegradability.
Abstract: Batch fermentation of 5, 10 and 25 g/L biodiesel
derived crude glycerol was carried out at 30, 37 and 450C by
Clostridium pasteurianum cells immobilized on silica. Maximum
yield of 1,3-propanediol (PDO) (0.60 mol/mol), and ethanol (0.26
mol/mol) were obtained from 10 g/L crude glycerol at 30 and 370C
respectively. Maximum yield of butanol (0.28 mol/mol substrate
added) was obtained at 370C with 25 g/L substrate. None of the three
products were detected at 45oC even after 10 days of fermentation.
Only traces of ethanol (0.01 mol/mol) were detected at 450C with 5
g/L substrate. The results obtained for 25 g/L substrate utilization
were fitted in first order rate equation to obtain the values of rate
constant at three different temperatures for bioconversion of glycerol.
First order rate constants for bioconversion of glycerol at 30, 37 and
45oC were found to be 0.198, 0.294 and 0.029/day respectively.
Activation energy (Ea) for crude glycerol bioconversion was
calculated to be 57.62 kcal/mol.
Abstract: Effect of viscosity of media on kinetic parameters of the coupled enzyme system NADH:FMN-oxidoreductase–luciferase was investigated with addition of organic solvents (glycerol and sucrose), because bioluminescent enzyme systems based on bacterial luciferases offer a unique and general tool for analysis of the many analytes and enzymes in the environment, research and clinical laboratories and other fields. The possibility of stabilization and increase of activity of the coupled enzyme system NADH:FMN-oxidoreductase–luciferase activity in vicious aqueous-organic mixtures have been shown.
Abstract: Biodiesel production results in glycerol production as
the main by-product in biodiesel industry.One of the utilizations of
glycerol obtained from biodiesel production is as a cement grinding
aid (CGA). Results showed that crude glycerol content was 40.19%
whereas pure glycerol content was 82.15%. BSS value of the cement
with CGA supplementation was higher than that of nonsupplemented
cement (blank) indicating that CGA-supplemented
cement had higher fineness than the non-supplemented one. It was
also found that pure glycerol 95% and TEA 5% at 80ºC was the
optimum CGA used to result in finest cement with BSS value of
4.836 cm2/g. Residue test showed that the smallest percent residue
value (0.11%) was obtained in cement with supplementation of pure
glycerol 95% and TEA 5%. Results of residue test confirmed those of
BSS test showing that cement with supplementation of pure glycerol
95% and TEA 5% had the finest particle size.
Abstract: A study was conducted to determine the effect of
feeding glycerol on dairy cows performance. Twenty four Holstein
Friesian crossbred (>87.5% Holstein Friesian) lactating dairy cows in
early lactation; averaging 13+2.4 kg of milk, 64+45 days in milk,
55+16 months old and 325+26 kg live weight, were stratified for
milk yield, days in milk, age, stage of lactation and body weight, and
then randomly allocated to three treatment groups. All cows were fed
approximate 8 kg of concentrate together with ad libitum corn silage
and freely access to clean water. Nil or 150 and 300g of glycerol
were supplemented to the cows according to treatment groups. All
cows consumed similar concentrate, corn silage and total DM and
NELP. There were no significant differences in DM intake, CP intake,
NELP intake, milk and milk composition yields. All cows had similar
fat, protein, lactose, solid not fat and total solid percentage. All cows
gain similar live weight. The present study indicated that,
supplementation of glycerol did not enhance milk yield, milk
composition and live weight change.
Abstract: Chemically defined Schlegel-s medium was modified
to improve production of cell growth and other metabolites that are
produced by fluorescent pseudomonad R62 strain. The modified
medium does not require pH control as pH changes are kept within ±
0.2 units of the initial pH 7.1 during fermentation. The siderophore
production was optimized for the fluorescent pseudomonad strain in
the modified medium containing 1% glycerol as a major carbon
source supplemented with 0.05% succinic acid and 0.5% Ltryptophan.
Indole-3 acetic acid (IAA) production was higher when
L-tryptophan was used at 0.5%. The 2,4- diacetylphloroglucinol
(DAPG) was higher with amended three trace elements in medium.
The optimized medium produced 2.28 g/l of dry cell mass and 900
mg/l of siderophore at the end of 36 h cultivation, while the
production levels of IAA and DAPG were 65 mg/l and 81 mg/l
respectively at the end of 48 h cultivation.