scholarly journals Chemical Free Two-Step Hydrothermal Pretreatment to Improve Sugar Yields from Energy Cane

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5805
Author(s):  
Ankita Juneja ◽  
Deepak Kumar ◽  
Vijay Kumar Singh ◽  
Yadvika ◽  
Vijay Singh
Keyword(s):  
Glucose Concentration ◽  
Degradation Products ◽  
Hydrothermal Pretreatment ◽  
Residence Times ◽  
Energy Cane ◽  
Pretreatment Condition ◽  
Lignocellulosic Feedstock ◽  
Pretreatment Temperature ◽  
Xylose Concentration

Energy cane is an attractive lignocellulosic feedstock for processing into biofuels and bioproducts. A low-severity two-step hydrothermal pretreatment was investigated on energy cane for the production of monomeric sugar. Pretreatment temperature and time, in addition to the effect of disk milling, were observed for the glucose and xylose yields during hydrolysis. At residence times above 5 min in case of pretreatment at 200 °C, all of the hemicellulose was observed to be solubilized. The pretreatment condition of 200 °C for 10 min with disk milling was observed to provide the highest glucose concentration of 5.4%, and 200 °C for 5 min with disk milling provided the highest xylose concentration of 2.15%. The effect of disk milling in improving the sugar concentrations during hydrolysis was significant, especially at lower pretreatment temperatures and times. Low xylose yields at higher temperatures were attributed to the formation of degradation products at increased severity.

scholarly journals Novel Kinetic Models of Xylan Dissolution and Degradation during Ethanol Based Auto-Catalyzed Organosolv Pretreatment of Bamboo

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1149 ◽  
Author(s):  
Jing Liu ◽  
Zhenggang Gong ◽  
Guangxu Yang ◽  
Lihui Chen ◽  
Liulian Huang ◽  
...  
Keyword(s):  
Kinetic Models ◽  
Degradation Products ◽  
Practical Significance ◽  
Order Kinetic ◽  
Organosolv Pretreatment ◽  
Dependent Parameter ◽  
Pretreatment Temperature ◽  
Pretreatment Conditions ◽  
Main Components ◽  
The Relationship

Due to the invalidity of traditional models, pretreatment conditions dependent parameter of susceptible dissolution degree of xylan (dX) was introduced into the kinetic models. After the introduction of dX, the dissolution of xylan, and the formation of xylo-oligosaccharides and xylose during ethanol based auto-catalyzed organosolv (EACO) pretreatments of bamboo were well predicted by the pseudo first-order kinetic models (R2 > 97%). The parameter of dX was verified to be a variable dependent of EACO pretreatment conditions (such as solvent content in pretreatment liquor and pretreatment temperature). Based on the established kinetic models of xylan dissolution, the dissolution of glucan and the formation of degradation products (furfural and acetic acid) could also be empirically modeled (R2 > 97%). In addition, the relationship between xylan and lignin removal can provide guidance for alleviating the depositions of lignin or pseudo-lignin. The parameter of dX derived novel kinetic models can not only be used to reveal the multi-step reaction mechanisms of xylan, but also control the final removal of main components in bamboo during EACO pretreatments, indicating scientific and practical significance for governing the biorefinery of woody biomass.

scholarly journals Volatile Fatty Acids and Biomethane Recovery from Thickened Waste Activated Sludge: Hydrothermal Pretreatment’s Retention Time Impact

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1580
Author(s):  
Farokh laqa Kakar ◽  
Ahmed El Sayed ◽  
Neha Purohit ◽  
Elsayed Elbeshbishy
Keyword(s):  
Fatty Acids ◽  
Activated Sludge ◽  
Retention Time ◽  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
Hydrothermal Pretreatment ◽  
Waste Activated Sludge ◽  
Optimum Conditions ◽  
Pretreatment Temperature ◽  
Biomethane Production

The main objective of this study was to evaluate the hydrothermal pretreatment’s retention time influence on the volatile fatty acids and biomethane production from thickened waste activated sludge under mesophilic conditions. Six different retention times of 10, 20, 30, 40, 50, and 60 min were investigated while the hydrothermal pretreatment temperature was kept at 170 °C. The results showed that the chemical oxygen demand (COD) solubilization increased by increasing the hydrothermal pretreatment retention time up to 30 min and stabilized afterwards. The highest COD solubilization of 48% was observed for the sample pretreated at 170 °C for 30 min. Similarly, the sample pretreated at 170 °C for 30 min demonstrated the highest volatile fatty acids yield of 14.5 g COD/Lsubstrate added and a methane yield of 225 mL CH4/g TCODadded compared to 4.3 g COD/Lsubstrate added and 163 mL CH4/g TCODadded for the raw sample, respectively. The outcome of this study revealed that the optimum conditions for solubilization are not necessarily associated with the best fermentation and/or digestion performance.

scholarly journals Effect of Hydrothermal Pretreatment on Volatile Fatty Acids Production from Source-Separated Organics

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 576 ◽  
Author(s):  
Farokh laqa Kakar ◽  
Ehssan Hosseini Koupaie ◽  
Hisham Hafez ◽  
Elsayed Elbeshbishy
Keyword(s):  
Fatty Acids ◽  
Chemical Oxygen Demand ◽  
Retention Time ◽  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
Hydrothermal Pretreatment ◽  
Soluble Substance ◽  
Pretreatment Temperature

The current study investigates the effect of hydrothermal pretreatment (HTP) on acidification of source-separated organics (SSO) in terms of volatile fatty acids (VFAs) production and solubilization. Temperature and retention time for HTP of SSO ranged from 150 to 240 °C and 5 to 30 min, respectively. The soluble substance after hydrothermal pretreatment initially increased, reaching its peak at 210 °C and then declined gradually. The highest overall chemical oxygen demand (COD) solubilization of 63% was observed at “210 °C-20 min” compared to 17% for raw SSO. The highest VFAs yield of 1536 mg VFAs/g VSS added was observed at “210 °C-20 min” compared to 768 mg VFAs/g VSS for raw SSO. Intensification of hydrothermal pretreatment temperature beyond 210 °C resulted in the mineralization of the organics and adversely affected the process.

scholarly journals Agronomic performance of the lignocellulosic feedstock crop energy cane in the Texas Rolling Plains

2020 ◽  
Vol 112 (5) ◽  
pp. 3816-3831
Author(s):  
Pramod Pokhrel ◽  
Nithya Rajan ◽  
John Jifon ◽  
William Rooney ◽  
Russell Jessup ◽  
...  
Keyword(s):  
Agronomic Performance ◽  
Energy Cane ◽  
Lignocellulosic Feedstock ◽  
Rolling Plains ◽  
Crop Energy

scholarly journals THE EFFECT OF HYDROTHERMAL PRETREATMENT ON THE ANAEROBIC DIGESTION OF THICKENED WASTE ACTIVATED SLUDGE AND SOURCE SEPARATED ORGANICS

2021 ◽  
Author(s):  
Ahmad Shabir Razavi
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Hydrothermal Pretreatment ◽  
Waste Activated Sludge ◽  
Pretreatment Condition ◽  
Wide Range ◽  
Biomethane Production ◽  
Pretreatment Conditions ◽  
The Impact ◽  
Severity Indexes

The objective of this study was to evaluate the impact of hydrothermal pretreatment of source separated organics (SSO) and thickened waste activated sludge (TWAS) on the solubilization and biomethane production. The feedstocks went through 15 different conditions in a wide range of temperature (150-240°C), retention time (5-30) min and severity indexes (3-5). The result of the study revealed that the effect of hydrothermal pretreatment can vary based on the feedstock primary properties and the optimum pretreatment condition. In this study, the optimum pretreatment conditions for highest solubilization and solid reduction of the SSO were 220°C and 10 minutes retention time, however, for highest methane production, it was 190°C for 20 minutes. In case of TWAS, the result revealed that the maximum biomethane production was achieved at pretreatment conditions of 160°C and 20 min, while, the highest solubilization and solid reduction was observed in 220°C and 10 minutes retention time.

scholarly journals Pseudo-lignin retarded bioconversion of sugarcane bagasse holocellulose after liquid hot water and acid pretreatments

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 4052-4063
Author(s):  
Haiyan Yang ◽  
Yuanchen Zhu ◽  
Yan Jin ◽  
Fuhou Lei ◽  
Zhengjun Shi ◽  
...  
Keyword(s):  
Sugarcane Bagasse ◽  
Low Temperatures ◽  
Degradation Products ◽  
Structural Characteristics ◽  
Hot Water ◽  
Acid Pretreatment ◽  
Liquid Hot Water ◽  
Carbohydrate Degradation ◽  
Pretreatment Temperature ◽  
Bioethanol Yield

Pseudo-lignin derived from the condensation of carbohydrate degradation products can retard the bioconversion of lignocellulose. In this work, liquid hot water (150 to 190 °C) and 1% H2SO4 pretreatments (130 to 190 °C) were used on sugarcane bagasse holocellulose for 3 h to generate pseudo-lignin. The effects of pseudo-lignin generation on structural characteristics and bioconversion of substrates were evaluated. The results showed that the formation of pseudo-lignin increased the hydrophobicity of the substrates. After LHW pretreatments and acid pretreatments at low temperatures (<150 °C), most of the xylans were removed, yielding 2.1 to 5.4% pseudo-lignin. Increasing acid pretreatment temperature to 170 and 190 °C yielded 34.3% and 93.6% pseudo-lignin, respectively. After pretreatment, the accessibilities and bioconversions of substrates were enhanced by degradation of xylans, increasing glucose conversions and bioethanol productions of substrates from 53.2 to 85.3%, and 9.9 to 13.1 g/L, respectively. However, large amounts of pseudo-lignin were generated during acid pretreatments at 170 °C, reducing glucose conversion and bioethanol yield to 45.6% and 6.3 g/L, respectively.

Reduced Glucose Degradation Products in Bicarbonate/Lactate-Buffered Peritoneal Dialysis Solutions Produced in Two-Chambered Bags

1997 ◽  
Vol 17 (4) ◽  
pp. 373-378 ◽  
Author(s):  
Laurinda A. Cooker ◽  
Patricia Luneburg ◽  
Dirk Faict ◽  
Carolyn Choo ◽  
Clifford J. Holmes
Keyword(s):  
Peritoneal Dialysis ◽  
Cell Growth ◽  
Glucose Concentration ◽  
Cultured Cells ◽  
Degradation Products ◽  
Neutral Red ◽  
Significant Inhibition ◽  
Glucose Degradation Products ◽  
Lower Glucose ◽  
Conventional Solution

Objectives The aims of the current study were: (1) to determine the effects of peritoneal dialysis (PD) solutions at different glucose concentrations on the growth of cultured cells; (2) to determine whether a bicarbonate/ lactate-based solution, as a result of the configuration of its components during heat sterilization in a two-chambered bag, was lower in glucose degradation products than a corresponding lactate-based PD solution; and (3) to determine whether lower glucose degradation corresponded to a decreased inhibition of cell growth. Design Growth inhibition of cells exposed to lactatebased PD solutions at three different glucose concentrations was determined. Bicarbonate/lactate-based and lactate-based solutions at high glucose concentration (3.86%) were further analyzed for presence of glucose degradation products and inhibition of cell growth. Methods Cell growth was determined by neutral red uptake, measured by optical density at 540 nm. Glucose degradation to acetaldehyde or fructose was determined by gas chromatographymass spectroscopy and highperformance liquid chromatography. Results Only 3.86% glucose lactate-based PD solution caused significant inhibition of cell growth (p < 0.05). The heat-sterilized, bicarbonate/lactate-based solution (3.86% glucose) had lower levels of fructose and acetaldehyde than a conventional heat-sterilized, lactatebased solution with the same glucose concentration. Growth of cultured cells exposed to the bicarbonate/ lactate-based solution was significantly improved (p < 0.05) over growth in the conventional solution. Conclusions The bicarbonate/lactate-based solutions, manufactured and heat-sterilized in two-chambered bags, were lower in glucose degradation products than the corresponding lactate-based PD solutions, and demonstrated improvedin vitrobiocompatibility as measured by the growth of cultured cells.

Degradation in Peritoneal Dialysis Fluids May be Avoided by Using Low pH and High Glucose Concentration

2001 ◽  
Vol 21 (4) ◽  
pp. 338-344 ◽  
Author(s):  
Per Kjellstrand ◽  
Evi Martinson ◽  
Anders Wieslander ◽  
Karin Kjellstrand ◽  
Elin Jeppsson ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Glucose Concentration ◽  
Degradation Products ◽  
Heating Time ◽  
Uv Absorbance ◽  
High Concentration ◽  
Number Of Factors ◽  
Initial Ph ◽  
Dialysis Fluids

Objective When glucose is present in a medical fluid, the heat applied during sterilization leads to degradation. The glucose degradation products (GDPs) give rise to bioincompatible reactions in peritoneal dialysis patients. The extent of the degradation depends on a number of factors, such as heating time, temperature, pH, glucose concentration, and catalyzing substances. In the present work, we investigated the influence of pH and concentration in order to determine how to decrease the amounts of GDPs produced. Design Glucose solutions (1% - 60% glucose; pH 1 - 8) were heat sterilized at 121°C. Ultraviolet (UV) absorption, aldehydes, pH, and inhibition of cell growth (ICG) were used as measures of degradation. Results Glucose degradation was minimum at an initial pH (prior to sterilization) of around 3.5 and at a high concentration of glucose. There was considerable development of acid degradation products during the sterilization process when the initial pH was high. Two different patterns of development of UV-absorbing degradation products were seen: one below pH 3.5, dominated by the formation of 5-hydroxy-methyl-2-furaldehyde (5-HMF); and one above, dominated by degradation products absorbing at 228 nm. 3-Deoxyglucosone (3-DG) concentration and the portion of 228 nm UV absorbance not caused by 5-HMF were found to relate to the in vitro bioincompatibility measured as ICG; there was no relation between 5-HMF or absorbance at 284 nm and bioincompatibility. Conclusion In order to minimize the development of bioincompatible GDPs in peritoneal dialysis fluids during heat sterilization, pH should be kept around 3.2 and the concentration of glucose should be high. 5-HMF and 284 nm UV absorbance are not reliable as quality measures. 3-DG and the portion of UV absorbance at 228 nm caused by degradation products other than 5-HMF seem to be reliable indicators of bioincompatibility.

How to Avoid Glucose Degradation Products in Peritoneal Dialysis Fluids

2006 ◽  
Vol 26 (4) ◽  
pp. 490-497 ◽  
Author(s):  
Martin Erixon ◽  
Anders Wieslander ◽  
Torbjörn Lindén ◽  
Ola Carlsson ◽  
Gunita Forsbäck ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
High Glucose ◽  
Glucose Concentration ◽  
Degradation Products ◽  
Minor Effect ◽  
High Glucose Concentration ◽  
Temperature Dependent ◽  
Glucose Degradation Products ◽  
A Minor ◽  
Dialysis Fluids

Objective The formation of glucose degradation products (GDPs) during sterilization of peritoneal dialysis fluids (PDFs) is one of the most important aspects of biocompatibility of glucose-containing PDFs. Producers of PDFs are thus trying to minimize the level of GDPs in their products. 3,4-Dideoxyglucosone-3-ene (3,4-DGE) has been identified as the most bioreactive GDP in PDFs. It exists in a temperature-dependent equilibrium with a pool of 3-deoxyglucosone (3-DG) and is a precursor in the irreversible formation of 5-hydroxymethyl furaldehyde (5-HMF). The aim of the present study was to investigate how to minimize GDPs in PDFs and how different manufacturers have succeeded in doing so. Design Glucose solutions at different pHs and concentrations were heat sterilized and 3-DG, 3,4-DGE, 5-HMF, formaldehyde, and acetaldehyde were analyzed. Conventional as well as biocompatible fluids from different manufacturers were analyzed in parallel for GDP concentrations. Results The concentrations of 3-DG and 3,4-DGE produced during heat sterilization decreased when pH was reduced to about 2. Concentration of 5-HMF decreased when pH was reduced to 2.6. After further decrease to a pH of 2.0, concentration of 5-HMF increased slightly, and below a pH of 2.0 it increased considerably, together with formaldehyde; 3-DG continued to drop and 3,4-DGE remained constant. Inhibition of cell growth was paralleled by 3,4-DGE concentration at pH 2.0 – 6.0. A high glucose concentration lowered concentrations of 3,4-DGE and 3-DG at pH 5.5 and of 5-HMF at pH 1. At pH 2.2 and 3.2, glucose concentration had a minor effect on the formation of GDPs. All conventional PDFs contained high levels of 3,4-DGE and 3-DG. Concentrations were considerably lower in the biocompatible fluids. However, the concentration of 5-HMF was slightly higher in all the biocompatible fluids. Conclusion The best way to avoid reactive GDPs is to have a pH between 2.0 and 2.6 during sterilization. If pHs outside this range are used, it becomes more important to have high glucose concentration during the sterilization process. There are large variations in GDPs, both within and between biocompatible and conventionally manufactured PDFs.

scholarly journals Biomethane production improvement by hydrothermal pretreatment of thickened waste activated sludge

2020 ◽  
Author(s):  
Ahmad Shabir Razavi ◽  
Farokhlaqa Kakar ◽  
Ehssan Hosseini Koupaie ◽  
Hisham Hafez ◽  
Elsayed Elbeshbishy
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Hydrothermal Pretreatment ◽  
Effect Of Temperature ◽  
Waste Activated Sludge ◽  
Pretreatment Condition ◽  
Production Improvement ◽  
Biomethane Production ◽  
Pretreatment Conditions ◽  
The Impact

Abstract This study evaluated the impact of hydrothermal pretreatment on thickened waste activated sludge (TWAS) for solubilization enhancement and biomethane production improvement through the mesophilic anaerobic digestion process. In order to assess the effect of temperature, retention time and severity index (SI) of the hydrothermal pretreatment, TWAS was exposed to fifteen different pretreatment condition within a combination of 10 different pretreatment temperature range (150–240 °C), five different retention time (5–30 min) and five different severity indexes (SI = 3, 3.5, 4, 4.5 and 5). The solubilization enhancement was observed in all hydrothermally pretreated samples with the highest solubilization efficiency of 49% in pretreatment condition of 200 °C and 10 min retention time within the corresponding SI = 4. Biomethane production was not improved in all fifteen pretreatment conditions, pretreatment with SI beyond 4 decreased the biodegradability of TWAS. The highest biomethane production was observed in the pretreatment condition of 170 °C and 10 min by 40% increase compared to non-pretreated TWAS.

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