scholarly journals Analysis of the beryllium stability under standard and critical operation in a fusion reactor

2021 ◽  
Vol 5 (4) ◽  
pp. 236-244
Author(s):  
K. Bekbayev ◽  
M. Akim ◽  
Zh. Nabiyeva
Keyword(s):  
Raw Materials ◽  
Soluble Sugars ◽  
Dilute Acid Pretreatment ◽  
Added Value ◽  
Limiting Factors ◽  
Efficient Production ◽  
Optimal Conditions ◽  
Acid Pretreatment ◽  
Metabolic Products ◽  
Valuable Product

Currently, dark fermentation is the most practically applicable for the implementation of biotechnological  roduction of hydrogen. However, this process has certain limiting factors, since a significant part of the substrates are converted into various metabolic products, but not into H2 . Therefore, it is necessary to develop optimal conditions for energy recovery in the form of gaseous molecular hydrogen. Various carbohydrate-containing raw materials for hydrogen production often require pretreatment before they can be used by microorganisms. Dilute acid pretreatment represents a promising way to increase biohydrogen production. However, during acid hydrolysis of carbohydrate-containing wastes, in addition to the released soluble sugars, inhibitors of enzymatic processing, such as furfural and 5-HMF, acetic and propionic acids, etc., can accumulate. In this regard, it is necessary to select the optimal conditions for the efficient production of biohydrogen. This study investigated the production of biohydrogen during the microbial fermentation of sugars in a dilute solution of a molasses-based acid hydrolyzate using Escherichia coli and a multiple mutant. The results of the experiments showed that molasses is a valuable product as a source of carbon and energy for microorganisms in the production of biohydrogen, as well as for the production of biomass for the further production of various products with high added value.

scholarly journals Genetic Engineering of Enterobacter asburiae Strain JDR-1 for Efficient Production of Ethanol from Hemicellulose Hydrolysates

2009 ◽  
Vol 75 (18) ◽  
pp. 5743-5749 ◽  
Author(s):  
Changhao Bi ◽  
Xueli Zhang ◽  
Lonnie O. Ingram ◽  
James F. Preston
Keyword(s):  
Ethanol Yield ◽  
Maximum Yield ◽  
Pyruvate Decarboxylase ◽  
Dry Weight ◽  
Dilute Acid Pretreatment ◽  
Efficient Production ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Acid Fermentation ◽  
Enterobacter Asburiae

ABSTRACT Dilute acid pretreatment is an established method for hydrolyzing the methylglucuronoxylans of hemicellulose to release fermentable xylose. In addition to xylose, this process releases the aldouronate methylglucuronoxylose, which cannot be metabolized by current ethanologenic biocatalysts. Enterobacter asburiae JDR-1, isolated from colonized wood, was found to efficiently ferment both methylglucuronoxylose and xylose in acid hydrolysates of sweet gum xylan, producing predominantly ethanol and acetate. Transformation of E. asburiae JDR-1 with pLOI555 or pLOI297, each containing the PET operon containing pyruvate decarboxylase (pdc) and alcohol dehydrogenase B (adhB) genes derived from Zymomonas mobilis, replaced mixed-acid fermentation with homoethanol fermentation. Deletion of the pyruvate formate lyase (pflB) gene further increased the ethanol yield, resulting in a stable E. asburiae E1(pLOI555) strain that efficiently utilized both xylose and methylglucuronoxylose in dilute acid hydrolysates of sweet gum xylan. Ethanol was produced from xylan hydrolysate by E. asburiae E1(pLOI555) with a yield that was 99% of the theoretical maximum yield and at a rate of 0.11 g ethanol/g (dry weight) cells/h, which was 1.57 times the yield and 1.48 times the rate obtained with the ethanologenic strain Escherichia coli KO11. This engineered derivative of E. asburiae JDR-1 that is able to ferment the predominant hexoses and pentoses derived from both hemicellulose and cellulose fractions is a promising subject for development as an ethanologenic biocatalyst for production of fuels and chemicals from agricultural residues and energy crops.

scholarly journals Water-Soluble Sugars of Pedigreed Sorghum Mutant Stalks and Their Recovery after Pretreatment

2020 ◽  
Vol 10 (16) ◽  
pp. 5472 ◽  
Author(s):  
Youjie Xu ◽  
Jun Li ◽  
Zhanguo Xin ◽  
Scott R. Bean ◽  
Michael Tilley ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Soluble Sugars ◽  
Water Soluble ◽  
Dilute Acid Pretreatment ◽  
Extractive Content ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Processing Technologies ◽  
Hemicellulose Removal ◽  
Dilute Sulfuric Acid Pretreatment

Chemical composition of biomass, especially carbohydrate content, is a critical indicator of a biomass source’s potential for biofuel applications. This study characterized physico-chemical properties of stalks from 16 representative pedigreed sorghum mutant lines. The objectives of this study were to evaluate the recovery of sucrose and its hydrolysis products, glucose and fructose, during dilute sulfuric acid pretreatment at conditions typically used for lignocellulosic biomass, and to determine the relationship between water-extractive contents and sugar recovery after pretreatment. Dilute acid-pretreated sorghum stalks had enzymatic saccharification of >82.4% glucose yield for all treated samples with more than 82.3% cellulose recovery and 85% hemicellulose removal. A single-step, one-pot process was recommended for sorghum mutant stalks with low water-extractive content (<35%, w/w) to reduce processing cost and minimize wastewater disposal since the majority of sugars will be recovered after dilute acid pretreatment with minimal degradation products. However, for sorghum mutant stalks with high water-extractive content (>35%, w/w), a pre-washing step is beneficial to recover the water-soluble sugars before subjecting to the pretreatment process in order to avoid sugar losses during the pretreatment stage. Thus, different processing technologies should be applied to lignocellulosic biomass with various water-extractive contents and water-soluble sugar concentrations.

scholarly journals Techno-economic feasibility of bioethanol production via biorefinery of olive tree prunings (OTP): optimization of the pretreatment stage

Holzforschung ◽  
2018 ◽  
Vol 73 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Juan C. Solarte-Toro ◽  
Juan M. Romero-García ◽  
Ana Susmozas ◽  
Encarnación Ruiz ◽  
Eulogio Castro ◽  
...  
Keyword(s):  
Olive Tree ◽  
Economic Feasibility ◽  
Operating Conditions ◽  
Raw Material ◽  
Dilute Acid Pretreatment ◽  
Bioethanol Production ◽  
Optimal Conditions ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Tree Pruning

Abstract The aim of this work was to evaluate the economic feasibility of the bioethanol production (BEP) based on olive tree pruning (OTP) as a biomass feedstock with optimization of the dilute acid pretreatment in focus. For this, the BEP was simulated taking into account the influence of the operating conditions of the pretreatment stage. Then, the techno-economic results were analyzed by means of the response surface methodology (RSM). The results show that lowest price of BE was 1.94 USD l−1 with a yield of 174.12 l t−1 OTP under optimal conditions. As a conclusion, the raw material cost has a strong influence in the economic feasibility of the BEP from OTP. The inclusion of other processing lines into the process would improve the process economy.

scholarly journals Insights on Monosaccharides and Bioethanol Production from Sweet Sorghum Stalks Using Dilute Acid Pretreatment

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1486
Author(s):  
Cristian-Teodor Buruiană ◽  
Luminița Georgescu ◽  
Simona-Florina Isticioaia ◽  
Oana Emilia Constantin ◽  
Camelia Vizireanu ◽  
...  
Keyword(s):  
Sweet Sorghum ◽  
Soluble Sugars ◽  
Dilute Acid Pretreatment ◽  
Bioethanol Production ◽  
Acid Pretreatment ◽  
Free Sugars ◽  
Acidic Pretreatment ◽  
Solid Phases ◽  
Ssf Process ◽  
Fermentative Process

Sweet sorghum is a unique bioenergy crop that produces stalks with fermentable free sugars. The purpose of this study was to evaluate how the production of hemicellulosic saccharides and bioethanol from sweet sorghum stalks (SSS) can be influenced by a dilute sulfuric acid (H2SO4) pretreatment under different isothermal conditions. The bioethanol production from untreated SSS and pretreated solid phases was achieved through the Simultaneous Saccharification and Fermentation (SSF) process. A good SSS fractionation and an extensive hemicellulose hydrolysis into soluble saccharides were obtained, the most abundant hemicellulose-derived compounds present in the pretreated liquid phase being monosaccharides, with up to 17.22 g/L of glucose and 16.64 g/L of xylose in the pretreatments performed with 3% and 1% H2SO4 for 30 min at 134 °C, respectively. The SSF process of untreated SSS allowed a maximum bioethanol concentration of 9.78 g/L, corresponding to a maximum glucan conversion into ethanol of 49.8%. Bioethanol production from untreated SSS led to a higher bioethanol concentration and conversion than in the case of using acid pretreated solid phases obtained under the most severe conditions (with 3% H2SO4 for 30, 60 and 120 min at 134 °C), suggesting that, in the case of this biomass naturally rich in soluble sugars, the acidic pretreatment could negatively influence the fermentative process.

Hydrolysis of Hazelnut Shells as a Carbon Source for Bioprocessing Applications and Fermentation

2014 ◽  
Vol 10 (4) ◽  
pp. 799-808 ◽  
Author(s):  
Sibel Uzuner ◽  
Deniz Cekmecelioglu
Keyword(s):  
Food Industry ◽  
Reducing Sugar ◽  
Dilute Acid Pretreatment ◽  
Fermentable Sugars ◽  
Optimal Conditions ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Total Carbohydrate ◽  
Hazelnut Shells ◽  
Hydrolysis Of

Abstract Hazelnut shells are generated in large amounts from hazelnut processing. Currently, it is used as fuel. However, reuse in bioprocessing can release remarkable content of sugars, which can be used for production of additives such as enzymes widely used in the food industry. Thus, the present study was undertaken to determine the effect of single and combined chemical and enzymatic hydrolysis on the production of fermentable sugars from hazelnut shells. Batch hydrolysis was carried out under various conditions to select optimal conditions. The results revealed that an optimal sugar concentration of about 19.2 g/l was achieved after 3.42% (w/w) dilute acid pretreatment conducted at 130°C for 31.7 min and enzymatic load of 200 U/g for 24 h. The overall sugar yield was calculated as 72.4% (g reducing sugar/g total carbohydrate). Therefore, hazelnut shells can be considered a suitable feedstock to compete with synthetic sugars used in fermentations.

PERSPECTIVE DEVELOPMENT OF WORLD PRODUCTION OF FEEDS FOR AQUACULTURE: ALTERNATIVE SOURCES OF RAW MATERIALS

2017 ◽  
pp. 67-78
Author(s):  
Lina Yurievna Lagutkina
Keyword(s):  
Raw Materials ◽  
Limiting Factors ◽  
Current Status ◽  
Feed Production ◽  
The World ◽  
Market Trends ◽  
Alternative Sources ◽  
World Industry ◽  
First Time ◽  
A Current

The author of the article discloses the prospects of development of the world feed production for aquaculture based on the analysis of key innovative technological and market trends. The author specifies that shortage, high cost, low ecological compatibility of traditional raw materials - fish flour - are among major limiting factors in the development of production of feeds for aquaculture. This fact, in turn, limits sustainable development of aquaculture both in Russia, and in the world in general. The article presents the overview of a current status of the world industry of feed production in aquaculture, where the regional situation is studied, as well. For the first time, there is given the outlook of innovative technologies in feed production based on the alternative sources of protein (on the example of projects of leading aquabiotechnological companies) which will determine industry’s objectives for the mid-term perspective.

scholarly journals Improvement of Enzymatic Saccharification of Cellulose-Containing Raw Materials Using Aspergillus niger

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1360
Author(s):  
Ekaterina Budenkova ◽  
Stanislav Sukhikh ◽  
Svetlana Ivanova ◽  
Olga Babich ◽  
Vyacheslav Dolganyuk ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Aspergillus Niger ◽  
Filter Paper ◽  
Raw Materials ◽  
Enzymatic Saccharification ◽  
Wood Chip ◽  
Cellulase Activity ◽  
Wood Chips ◽  
Acid Pretreatment ◽  
Hydrolysis Of

Enzymatic hydrolysis of cellulose-containing raw materials, using Aspergillus niger, were studied. Filter paper, secondary cellulose-containing or starch-containing raw materials, miscanthus cellulose after alkaline or acid pretreatment, and wood chip cellulose, were used as substrates. The study focused on a wild A. niger strain, treated, or not (control), by ultraviolet (UV) irradiations for 45, 60, or 120 min (UV45, UV60, or UV120), or by UV irradiation for 120 min followed by a chemical treatment with NaN3 + ItBr for 30 min or 80 min (UV120 + CH30 or UV120 + CH80). A mixture of all the A. niger strains (MIX) was also tested. A citrate buffer, at 50 mM, wasthe most suitable for enzymatic hydrolysis. As the UV exposure time increased to 2 h, the cellulase activity of the surviving culturewas increased (r = 0.706; p < 0.05). The enzymatic activities of the obtained strains, towards miscanthus cellulose, wood chips, and filter paper, were inferior to those obtained with commercial enzymes (8.6 versus 9.1 IU), in some cases. Under stationary hydrolysis at 37 °C, pH = 4.7, the enzymatic activity of A. niger UV120 + CH30 was 24.9 IU. The enzymatic hydrolysis of secondary raw materials, using treated A. niger strains, was themost effective at 37 °C. Similarly, the most effective treatment of miscanthus cellulose and wood chips occurred at 50 °C. The maximum conversion of cellulose to glucose was observed using miscanthus cellulose (with alkaline pretreatment), and the minimum conversion was observed when using wood chips. The greatest value of cellulase activity was evidenced in the starch-containing raw materials, indicating that A. niger can ferment not only through cellulase activity, but also via an amylolytic one.

scholarly journals Understanding the effects of different residual lignin fractions in acid-pretreated bamboo residues on its enzymatic digestibility

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Wenqian Lin ◽  
Jinlai Yang ◽  
Yayue Zheng ◽  
Caoxing Huang ◽  
Qiang Yong
Keyword(s):  
Enzymatic Hydrolysis ◽  
Negative Impact ◽  
Dilute Acid Pretreatment ◽  
Residual Lignin ◽  
Dilute Acid ◽  
Enzymatic Digestibility ◽  
Acid Pretreatment ◽  
Organic Reagents ◽  
Milled Wood Lignin ◽  
Affinity Constants

Abstract Background During the dilute acid pretreatment process, the resulting pseudo-lignin and lignin droplets deposited on the surface of lignocellulose and inhibit the enzymatic digestibility of cellulose in lignocellulose. However, how these lignins interact with cellulase enzymes and then affect enzymatic hydrolysis is still unknown. In this work, different fractions of surface lignin (SL) obtained from dilute acid-pretreated bamboo residues (DAP-BR) were extracted by various organic reagents and the residual lignin in extracted DAP-BR was obtained by the milled wood lignin (MWL) method. All of the lignin fractions obtained from DAP-BR were used to investigate the mechanism for interaction between lignin and cellulase using surface plasmon resonance (SPR) technology to understand how they affect enzymatic hydrolysis Results The results showed that removing surface lignin significantly decreased the yield for enzymatic hydrolysis DAP-BR from 36.5% to 18.6%. The addition of MWL samples to Avicel inhibited its enzymatic hydrolysis, while different SL samples showed slight increases in enzymatic digestibility. Due to the higher molecular weight and hydrophobicity of MWL samples versus SL samples, a stronger affinity for MWL (KD = 6.8–24.7 nM) was found versus that of SL (KD = 39.4–52.6 nM) by SPR analysis. The affinity constants of all tested lignins exhibited good correlations (r > 0.6) with the effects on enzymatic digestibility of extracted DAP-BR and Avicel. Conclusions This work revealed that the surface lignin on DAP-BR is necessary for maintaining enzyme digestibility levels, and its removal has a negative impact on substrate digestibility.

Sign in / Sign up

Export Citation Format

Share Document