Increase In Pretreatment Time Research Articles

Comparative evaluation of the effect of ultrasonic pretreatment at different temperatures on enhancing anaerobic digestion of rumen wastes

The aim of this study was to determine the most appropriate treatment for the duration of ultrasonic pretreatment at two different temperatures in the process of anaerobic digestion (AD) of ruminal contents in the slaughterhouse. The experiments were performed at the Golshan industrial slaughterhouse in Lorestan province. In this study, after homogenizing the rumen contents of different animals, the effect of ultrasonic pretreatment time at three different intervals of 10, 20, and 30 min at two different temperatures of 30 °C and 40 °C was investigated to determine the effect of variables related to the trend of changes in methane, total biogas, and daily biogas production. The Taguchi L18 method was used to investigate the process conditions and achieve optimal production conditions for biogas methane. The results showed that with an increase in pretreatment time up to 30 min and the temperature up to 40 °C, the production of biogas and methane also increased. The highest amount of methane, total biogas, and daily biogas produced was related to the use of ultrasonic pretreatment for 30 min at 40 °C with 50.66 % methane, total biogas production of 332.66 mL/gVS, and the best performance compared to other treatments in the shortest possible time. Therefore, the use of ultrasonic pretreatment over longer periods and at higher temperatures improves the AD process and produces more total methane and biogas. Finally, this research presented equations for the production of biogas and methane at a time of 10–30 min and a temperature of 30–40 °C, which showed high accuracy.

Altered Skin Permeation of Finasteride Using Clove Oil, Urea, and Lyophilized Powder of Grape Seed Extract.

Purpose: Finasteride is a 5-alpha reductase inhibitor used to treat hair loss and acne. The skin permeation of finasteride is one of the main challenges associated with dermal drug delivery. One way to overcome the skin barrier is to use penetration enhancers. The purpose of this study was to investigate the effect of some penetration enhancers on finasteride permeability on the skin, as well as the effect of pretreatment time on their efficacy. Methods: In order to determine the effect of penetration enhancers on the skin permeability of finasteride, the skin was exposed to clove oil, urea, and lyophilized powder of grape seed extract (LPGSE) at different pretreatment times (2, 4 h), and then the permeability parameters were determined by passing the drug through the skin. Results: The results of this study showed that clove oil, urea, and LPGSE increased the transfer of finasteride from the skin. The highest rate of permeation was observed with clove oil (4 h), and the least permeability was observed with urea (4 h). Conclusion: Increasing the pretreatment time with clove oil and LPGSE increases the permeability of finasteride. Meanwhile, the increase in pretreatment time with urea reduces the penetration of finasteride from the skin due to reversible effects.

Chemical composition and porcine in vitro digestibility of corn whole stillage pretreated with heat at various temperatures and times

A study was conducted to identify optimal conditions (time and temperature) for heat pre-treatment of corn whole stillage (WS). Six samples of WS from different sources were divided into 13 sub-samples to give a total of 78 sub-samples. Thirteen treatments were applied to 13 sub-samples from each source (1 sub-sample/treatment). The treatments were untreated WS, and WS that was pre-treated (70 psi) for 10, 20, or 30 min and at 100, 120, 140, or 160 °C in a 3 × 4 factorial treatment arrangement. Sub-samples were subjected to in vitro digestion with porcine pepsin and pancreatin, followed by in vitro fermentation for 72 h. Accumulated gas production was recorded and modeled to estimate kinetics of gas production. Heat pretreatment of WS at ≥ 120 °C decreased (P < 0.05) its total dietary fiber (TDF) and chemically available lysine content by approximately 10 and 19 %, respectively; and increased (P < 0.05) total furans (TF) content from 0.50 to approximately 154 mg/kg. Pretreatment time and temperature interacted on TDF and TF content in WS, such that an increase in pretreatment time had no effect on TDF and TF content in WS when pretreated at 100, 120, or 140°C, but reduced (P < 0.05) TDF content and increased (P < 0.05) TF content in WS when pretreated at 160°C. Pretreatment time and temperature interacted (P < 0.05) on chemically available lysine content of WS, such that an increase in pretreatment time unaffected chemically available lysine content when the WS was pretreated at 100 or 120 °C, but reduced (P < 0.05) chemically available lysine content when the WS was pretreated at 140 or 160 °C. Pre-treatment time and temperature did not interact on in vitro disappearance of dry matter (IVD-DM), and total gas production. The coefficient of IVD-DM for untreated WS was 0.734. An increase in pre-treatment temperature from 0 to 160 °C resulted in linear increase (P < 0.05) in coefficient of IVD-DM by 13 %, and of total gas production by 16 %. Response surface analysis indicated that maximum coefficient of IVD-DM and total gas production resulted from longer pretreatment times (20–30 min) and highest pretreatment temperature, whereas maximum chemically available lysine content resulted from pretreatment at 100 °C for 20 min. In conclusion, the optimal conditions for pretreatment of WS for production of distillers dried grains with solubles of improved digestibility and fermentability by pigs were temperature of 140–160 °C, and duration of approximately 20 min.

Modifying crystallinity, and thermo-optical characteristics of Paulownia biomass through ultrafine grinding and evaluation of biohydrogen production potential

Exploring the clean and low cost biohydrogen production technology with vastly spread forestry based biomass highlights the practical large scale biohydrogen production prospective. In the present work we exploited the role of ultrafine pretreatment to Paulownia biomass as a sole carbon source to evaluate biohydrogen production potential. The altered physical, thermal and optical characteristics of Paulownia biomass after pretreatment of ultrafine grinding were compared with well-studied biomass of corn stover. Microstructural, FTIR and TGA analysis highlight the deterioration of crystal structure and lignin breaking of cellulose with increase in pretreatment time, which significantly improves hydrolysis and enhances hydrogen production subsequently. In comparison to raw materials, Paulownia leaves have the highest hydrogen production potential whereas after pretreatment, total hydrogen yield from Paulownia stems is increased by 51.8% which is comparable to corn stover. Our results highlight that in comparison to conventional agriculture stover, lignocellulosic Paulownia biomass can be potential candidate for clean energy production with prospective of sustainable supply.

English

One of the best options for African countries to meet rural energy needs is to grow care-free crassulacean acid metabolism plants on a massive scale in waste lands. This can enable bioenergy production without disrupting food supplies and hence sustainable energy supply for the future. Opuntia ficus indica is an ideal plant for arid regimes but has barely been studied as a potential bioenergy source. This study investigated the effect of aerobic pretreatment on methane yield of O. ficus indica biomass. This effect was investigated in batch bioreactors which were exposed to aerobic conditions by varying time from 3 to 72 h before the start of anaerobic digestion. Reducing sugar content and dissolved oxygen levels after pretreatment period was analyzed. Reducing sugar content in bioreactors increased with increase in pretreatment time from 12.22 &plusmn;0.69 to 59.08 &plusmn; 5.35 g/L in the untreated and 72 h pretreated batches, respectively. Methane yields after pretreatment were observed to range from 0.286 to 0.702 L/kg volatile solids at 9 and 72 h of pre-treatment, respectively. A 9 h pre-treatment of feedstock prior to anaerobic digestion yielded 123% higher methane yield when compared to that without pre-treatment. The findings that there was an&nbsp; increase in reducing sugar production and methane yield at 9 h of aerobic pre-treatment suggests that there was increased hydrolysis with pretreatment. Hence, short pre-treatment period could be an option to increasing solubilization of cladodes and promoting methane productivity. Therefore, pre-aeration of O. ficus indica, was shown to be an effective method for enhancing both its digestibility and improved methane yield during anaerobic digestion. &nbsp; Key words: Anaerobic digestion, biogas, methane, Opuntia, pretreatment, spineless cacti.

Improvement of dry simultaneous saccharification and fermentation of rice straw to high concentration ethanol by sodium carbonate pretreatment

Ethanol at high concentration was produced from rice straw pretreated with sodium carbonate through dry simultaneous saccharification and fermentation (DSSF). A high concentration of ethanol was obtained without mechanical mixing, an increase in fermentation time, and pre-hydrolysis. The most important influencing factors, including pretreatment time (3–10 h), enzyme loading (5–40 FPU/g substrate), solid loading (15–30 wt %), and DSSF reaction time (48–120 h), were investigated on dry hydrolysis and DSSF. An increase in pretreatment time from 3 to 10 h improved ethanol concentration from 55.1 to 67.7 g/L, obtained through DSSF at 20% solid loading and 10 FPU/g substrate. A glucose concentration as high as 124.6 g/L was obtained from the hydrolysis of the straw treated for 5 h. The highest total sugar and ethanol concentration were 137.3 g/L and 83.1 g/L for the treated straw, while they were 65.2 g/L and 38.6 g/L for the untreated ones, respectively, obtained by hydrolysis and DSSF at 30% solid loading. Changes associated with pretreatment, i.e., composition, crystallinity, and microscopic structure of untreated and treated straws, were investigated to find the reason for the improved hydrolysis and DSSF.

Pyrolysis characteristics of poplar sawdust by pretreatment of anaerobic fermentation

Pyrolysis characteristics of poplar sawdust (PS) pretreated by anaerobic fermentation were investigated by means of thermogravimetric analysis (TGA) and pyrolysis-gas chromatograph/mass spectrometry (Py-GC/MS) analysis. Results indicated that with an increase of pretreatment time from 0 to 20 days, the contents of cellulose and hemicellulose decreased from 54.05 and 17.96 wt. % to 51.29 and 12.61wt. % and the contents of the extractives and lignin increased from 1.41 and 26.58 wt. % to 7.31and 28.19 wt. %, respectively. The bio-pretreatment enhanced the starting pyrolysis temperature and increased the remains at 700 °C. Distinct weight loss of cellulose between 250–350 °C were observed at the TGA curves of P5, P10 and P20. Activation energy increased from 87.90 to 103.21 kJ mol−1. The bio-oil yield and product distributions also changed. Sugars content firstly increased from 7.64 to 16.73% and then decreased to 13.70%. The content of linear carbonyls initially decreased from 12.40 to 8.64% and then increased to 14.39%. Phenols show similar changing pattern. Its content changed from 24.72 to 22.54 and then 25.03%. The contents of linear acids, linear ketones and furans decreased. The contents of laevoglucose, hydroxyl acetaldehyde and 1, 2-benzenediol in the bio-oil increased from 4.54, 10.78 and 3.07% to 12.30, 13.30 and 5.44%, respectively. This indicated the pyrolysis selectivity of PS was improved. Effects of anaerobic fermentation on wood pyrolysis behaviors were remarkably different not only from straw biomass but from that of white- and brown-rot fungi.

Rapid cryopreservation for Siraitia grosvenorii cells based on cells' capacitance detection

A rapid quantitative evaluation method for Siraitia grosvenorii cells was successfully developed based on plant cells' capacitance value detected by a viable cell mass monitor and the cryopreservation of S. grosvenorii suspension cells was optimized. The survival rate of S. grosvenorii cells was quantitatively measured by viable cell mass monitor and 2, 3, 5-triphenyltetrazolium chloride (TTC). An optimum cryoprotectant recipe is that the growth medium contained 10% sucrose and 10% DMSO. The experimental results also showed higher cell survival rates and cell viabilities were achieved when suspension cells were treated with pretreatment of 0.2 mol/L sucrose. With the increase of concentration of sucrose, however, the cell survival rate was decreased. And the cell survival rate represented a bell shape with the increase of pretreatment time. The highest cell survival rate and cell viability were obtained with the 9 h' s pretreatment. In addition, there was a good correlation between the cell survival rate measured by cell recovery test and that measured by viable cell mass monitor, while there were no significant differences in the cell morphology and the ability of mogrosides V production by S. grosvenorii cells cultured in suspension after cryopreservation. Therefore, the evaluation method developed based on the viable cell mass monitor has good feasibility and reliability.

Ultrasonic waste activated sludge disintegration for recovering multiple nutrients for biofuel production

Waste activated sludge is a valuable resource containing multiple nutrients, but is currently treated and disposed of as an important source of pollution. In this work, waste activated sludge after ultrasound pretreatment was reused as multiple nutrients for biofuel production. The nutrients trapped in sludge floc were transferred into liquid medium by ultrasonic disintegration during first 30 min, while further increase of pretreatment time only resulted in slight increase of nutrients release. Hydrogen production by Ethanoligenens harbinense B49 from glucose significantly increased with the concentration of ultrasonic sludge, and reached maximum yield of 1.97 mol H2/mol glucose at sludge concentration of 7.75 g volatile suspended solids/l. Without addition of any other chemicals, waste molasses rich in carbohydrate was efficiently turned into hydrogen with yield of 189.34 ml H2/g total sugar by E. harbinense B49 using ultrasonic sludge as nutrients. The results also showed that hydrogen production using pretreated sludge as multiple nutrients was higher than those using standard nutrients. Acetic acid produced by E. harbinense B49 together with the residual nutrients in the liquid medium were further converted into hydrogen (271.36 ml H2/g total sugar) by Rhodopseudomonas faecalis RLD-53 through photo fermentation, while ethanol was the sole end product with yield of 220.26 mg/g total sugar. Thus, pretreated sludge was an efficient nutrients source for biofuel production, which could replace the standard nutrients. This research provided a novel strategy to achieve environmental friendly sludge disposal and simultaneous efficient biofuel recovery from organic waste.

The Effects of Amplitudes Ultrasound-Assisted Solvent Extraction and Pretreatment Time on the Yield and Quality of Pistacia Khinjuk Hull Oil.

In this study, the effect of three amplitudes of ultrasound-assisted solvent extraction (UASE) (0, 25 and 50 %; 100 W, 30 kHz; the 0% treatment serving as control) on yield and quality of extracted oil from P. khinjuk hull at various pretreatment times (15, 30 and 45 min) was evaluated. The highest oil yields at the three amplitude levels tested were 24.4, 29.8 and 37.8% for 0, 25 and 50 %, respectively. Although increase in pretreatment time increased oil yield, pretreatment time at 30 and 45 min did not significantly different for both 25 and 50% amplitude. Furthermore, UASE did not significantly affect fatty acid composition, peroxide value (PV), conjugated diene value (CDV) and anisidine value (AnV) of extracted oils. UASE also increased tocopherols and tocoterienols content of oils but pretreatment time at 30 and 45 min did not significantly different for them. Therefore, UASE increase yield and quality of extracted oil and reduce extraction time. All these advantages make UASE a good substitute for the extraction of oil.

Effect of poly(amidoamine) (PAMAM) dendrimer on skin permeation of 5-fluorouracil

The aim of present study is to investigate the effect of poly(amidoamine) (PAMAM) dendrimer on skin permeation of 5-fluorouracil (5FU). Permeation studies were performed using excised porcine skin in a Franz diffusion cell and 14C labeled 5FU samples were analyzed using liquid scintillation counter. Three different vehicles were used, including phosphate buffer (PB), mineral oil (MO) and isopropyl myristate (IPM). The studies were carried out by simultaneously applying the drug and dendrimer together or by pre-treating the skin with dendrimer before drug application. Simultaneous application of drug and dendrimer increased the flux of 5FU in IPM and MO, while there was no change in PB. The increased skin partitioning of dendrimer from lipophilic vehicles increased the drug solubility in skin. Pre-treatment with dendrimer increased permeability coefficient of 5FU by 4-fold in MO and 2.5-fold in IPM, while it decreased by half in PB. Skin partitioning of 5FU increased after dendrimer treatment from lipophilic vehicles. The flux increased linearly with increase in pre-treatment time. Dendrimer pre-treatment increased transepidermal water loss and decreased skin resistance. The decrease in skin resistance directly correlated to the enhancement in skin permeation of 5FU ( r 2 = 0.99). Overall, the study showed that dendrimer increases the skin permeation of 5FU from lipophilic vehicles mainly by altering the skin barrier.

Adapalene pretreatment increases follicular penetration of clindamycin: &lt;i&gt;In vitro&lt;/i&gt; and &lt;i&gt;in vivo&lt;/i&gt; studies

Topical retinoids normalize desquamation, reduce comedogenesis and may enhance the penetration of other topicals providing more effective treatment of acne. We evaluated the effect of adapalene on skin penetration of clindamycin phosphate when it is applied concomitantly or after various time durations following adapalene application. The in vitro studies were carried out using excised rat skin, whereas the in vivo studies were conducted on healthy human volunteers. Radioactive clindamycin phosphate (1%) gel was applied to rat skin sections and to the hands of human volunteers concomitantly and after the pretreatment of the skin for 3, 5 and 10 min with 10 mg of adapalene (0.1%) gel. Quantification of clindamycin phosphate was performed by liquid scintillation. In vitro skin penetration and distribution of clindamycin phosphate was affected by the pretreatment time. Significantly higher skin concentration of clindamycin phosphate (15.5%) with largest proportion in viable skin layer (9.4% of applied dose) was found when clindamycin phosphate gel was applied after the pretreatment of the skin with adapalene gel for 5 min. Further increase in pretreatment time has no additive influence on the penetration of clindamycin phosphate. In vivo results were in corroboration with the in vitro results and demonstrate significantly higher concentration of clindamycin phosphate (19%) in the skin following pretreatment with adapalene gel for 5 min. Adapalene acts as a penetration enhancer and increases the penetration of topical clindamycin phosphate. Application of clindamycin phosphate gel after the pretreatment of skin with adapalene gel for 5 min may contribute significantly to the increased efficacy of therapy.