scholarly journals Rice Straws With Different Cell Wall Components Differ on Abilities of Saccharification

2021 ◽  
Vol 8 ◽  
Author(s):  
Chen Chen ◽  
Xiaoxiao Deng ◽  
Weilong Kong ◽  
Mirza Faisal Qaseem ◽  
Shuai Zhao ◽  
...  
Keyword(s):  
Cell Wall ◽  
Energy Use ◽  
Treatment Strategies ◽  
Wall Structure ◽  
High Concentration ◽  
Acid Pretreatment ◽  
Rice Varieties ◽  
Glucose Yield ◽  
High Acid ◽  
High Alkali

Rice straw has an enormous amount of biomass for energy use, but the complexity of the cell wall component hinders technical processes. Although belonging to rice straws, the straws from different varieties should be with different treatment strategies to obtain best energy efficiency. To confirm this hypothesis, 7 different rice varieties (RPY GENG, RIL269, RIL272, RIL31, RIL57, RIL06, LUOHUI 9) with different cell wall traits from RIL population were evaluated for their response toward different pretreatments. For japonica RPY GENG, 2% of H2SO4 acid was best pre-treatment while high acid (5% of H2SO4) pretreatment caused undue loss. For Indica LUOHUI 9 rice, high acid pretreatment was suitable, while RIL57 had maximum of glucose yield with high alkali (10% NaOH) pretreatment. High-concentration alkali pretreatment is the most convenient and effective pretreatment method for the treatment of unknown varieties of rice straws, because the lignin has been removed and has the lowest negative effects on the glucose yield under the high alkali condition. As the RILs used in this study vary considerably in their wall structure, an understanding of their response to different pre-treatments confirms our hypothesis and help us to understand the influence of different wall compositions on the final output.

scholarly journals Alkaline post-incubation improves the saccharification of poplar after hydrogen peroxide–acetic acid pretreatment

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Peiyao Wen ◽  
Ying Zhang ◽  
Junjun Zhu ◽  
Yong Xu ◽  
Junhua Zhang
Keyword(s):  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Enzymatic Hydrolysis ◽  
High Concentration ◽  
Acid Pretreatment ◽  
Glucose Yield ◽  
Selective Delignification ◽  
Acetyl Group ◽  
The Cost ◽  
Total Lignin

Abstract Background Hydrogen peroxide–acetic acid (HPAA) is widely used in pretreatment of lignocellulose because it has a good capability in selective delignification. However, high concentration (more than 60%) of HPAA increases the cost of pretreatment and the risk of explosion. In this work, alkaline post-incubation was employed to decrease the HPAA loading and improve the saccharification of poplar. Results Pretreatment with 100% HPAA removed 91.0% lignin and retained 89.9% glucan in poplar. After poplar was pretreated by 100% HPAA at 60 °C for 2 h, the glucan conversion in enzymatic hydrolysis by cellulase increased to 90.1%. Alkaline incubation reduced the total lignin, surface lignin, and acetyl group of HPAA-pretreated poplar. More than 92% acetyl groups of HPAA-pretreated poplar were removed by alkaline incubation with 1.0% NaOH at 50 °C for 1 h. After incubation of 60% HPAA-pretreated poplar with 1.0% NaOH, the glucan conversion enhanced to 95.0%. About 40% HPAA loading in pretreatment was reduced by alkaline incubation without the decrease of glucose yield. Conclusions Alkaline post-incubation had strong ability on the deacetylation and delignification of HPAA-pretreated poplar, exhibiting a strong promotion on the enzymatic hydrolysis yield. This report represented alkaline incubation reduced the HPAA loading, improved pretreatment safety, exhibiting excellent potential application in saccharification of poplar.

Optimization of Dilute Acid Hydrolysis of Corn Stover for Separate Production of Xylose and Glucose by Response Surface Methodology

2012 ◽  
Vol 608-609 ◽  
pp. 298-301
Author(s):  
Su Li Zhi ◽  
Jing Yang ◽  
Yan Yao ◽  
Shu Ting Zhang ◽  
Xue Bin Lu
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Corn Stover ◽  
High Concentration ◽  
Dilute Acid Hydrolysis ◽  
Acid Pretreatment ◽  
Glucose Yield ◽  
H2so4 Concentration ◽  
Glucose Ratio ◽  
Dilute Sulfuric Acid Pretreatment

Dilute sulfuric acid pretreatment of corn stover was used to obtain a solution of high concentration of xylose from the hemicellulosic fraction and a relatively low concentration of glucose, which not only saved the hemicellulase but also made a full use of corn stover. Then the study considered the selectivity (xylose-glucose ratio) as an important parameter to optimize the hydrolysis conditions. The results optimized by response surface methodology (RSM) showed that the optimum conditions for pretreatment were found to be H2SO4 concentration of 2.4% and reaction time of 100min at 100°C. Under these conditions, 78.8% of xylose yield was achieved and the glucose yield was lower than 11.6%. To confirm these results, the optimum condition was performed and the actual results of xylose yield and glucose yield were 78% and 11.3%.

scholarly journals Saccharification Potential of Transgenic Greenhouse- and Field-Grown Aspen Engineered for Reduced Xylan Acetylation

2021 ◽  
Vol 12 ◽  
Author(s):  
Sivan Pramod ◽  
Madhavi Latha Gandla ◽  
Marta Derba-Maceluch ◽  
Leif J. Jönsson ◽  
Ewa J. Mellerowicz ◽  
...  
Keyword(s):  
Cell Wall ◽  
Lignin Content ◽  
Chemical Properties ◽  
Complex Relationship ◽  
Hybrid Aspen ◽  
Wild Type ◽  
Acid Pretreatment ◽  
Glucose Yield ◽  
Genes Encoding ◽  
Acetylation Pattern

High acetylation of xylan in hardwoods decreases their value as biorefinery feedstocks. To counter this problem, we have constitutively suppressed RWA genes encoding acetyl-CoA transporters using the 35S promoter, or constitutively and wood-specifically (using the WP promoter) expressed fungal acetyl xylan esterases of families CE1 (AnAXE1) and CE5 (HjAXE), to reduce acetylation in hybrid aspen. All these transformations improved the saccharification of wood from greenhouse-grown trees. Here, we describe the chemical properties and saccharification potential of the resulting lines grown in a five-year field trial, and one type of them (WP:AnAXE1) in greenhouse conditions. Chemically, the lignocellulose of the field- and greenhouse-field-grown plants slightly differed, but the reductions in acetylation and saccharification improvement of engineered trees were largely maintained in the field. The main novel phenotypic observation in the field was higher lignification in lines with the WP promoter than those with the 35S promoter. Following growth in the field, saccharification glucose yields were higher from most transformed lines than from wild-type (WT) plants with no pretreatment, but there was no improvement in saccharification with acid pretreatment. Thus, acid pretreatment removes most recalcitrance caused by acetylation. We found a complex relationship between acetylation and glucose yields in saccharification without pretreatment, suggesting that other variables, for example, the acetylation pattern, affect recalcitrance. Bigger gains in glucose yields were observed in lines with the 35S promoter than in those with the WP promoter, possibly due to their lower lignin content. However, better lignocellulose saccharification of these lines was offset by a growth penalty and their glucose yield per tree was lower. In a comparison of the best lines with each construct, WP:AnAXE1 provided the highest glucose yield per tree from saccharification, with and without pretreatment, WP:HjAXE yields were similar to those of WT plants, and yields of lines with other constructs were lower. These results show that lignocellulose properties of field-grown trees can be improved by reducing cell wall acetylation using various approaches, but some affect productivity in the field. Thus, better understanding of molecular and physiological consequences of deacetylation is needed to obtain quantitatively better results.

Bacterial Peptidoglycan Stapling with Functionalized D-Amino Acids

2019 ◽  
Author(s):  
Sylvia L. Rivera ◽  
Akbar Espaillat ◽  
Arjun K. Aditham ◽  
Peyton Shieh ◽  
Chris Muriel-Mundo ◽  
...  
Keyword(s):  
Cell Wall ◽  
Clinical Success ◽  
Bacterial Species ◽  
Enzymatic Reaction ◽  
Amino Acid Derivative ◽  
Wall Structure ◽  
Live Bacteria ◽  
Cross Links ◽  
Osmotic Lysis ◽  
Bacterial Peptidoglycan

Transpeptidation reinforces the structure of cell wall peptidoglycan, an extracellular heteropolymer that protects bacteria from osmotic lysis. The clinical success of transpeptidase-inhibiting β-lactam antibiotics illustrates the essentiality of these cross-linkages for cell wall integrity, but the presence of multiple, seemingly redundant transpeptidases in many bacterial species makes it challenging to determine cross-link function precisely. Here we present a technique to covalently link peptide strands by chemical rather than enzymatic reaction. We employ bio-compatible click chemistry to induce triazole formation between azido- and alkynyl-D-alanine residues that are metabolically installed in the cell walls of Gram-positive and Gram-negative bacteria. Synthetic triazole cross-links can be visualized by substituting azido-D-alanine with azidocoumarin-D-alanine, an amino acid derivative that undergoes fluorescent enhancement upon reaction with terminal alkynes. Cell wall stapling protects the model bacterium Escherichia coli from β-lactam treatment. Chemical control of cell wall structure in live bacteria can provide functional insights that are orthogonal to those obtained by genetics.<br>

Recent Developments in the Downstream Processing of Phycobiliproteins from Algae: A Review

2021 ◽  
Vol 06 ◽  
Author(s):  
Ayekpam Chandralekha Devi ◽  
G. K. Hamsavi ◽  
Simran Sahota ◽  
Rochak Mittal ◽  
Hrishikesh A. Tavanandi ◽  
...  
Keyword(s):  
Cell Wall ◽  
Large Scale ◽  
Downstream Processing ◽  
Review Article ◽  
Current Status ◽  
Wall Structure ◽  
Scale Production ◽  
Cell Wall Disruption ◽  
Recent Developments ◽  
Macro Algae

Abstract: Algae (both micro and macro) have gained huge attention in the recent past for their high commercial value products. They are the source of various biomolecules of commercial applications ranging from nutraceuticals to fuels. Phycobiliproteins are one such high value low volume compounds which are mainly obtained from micro and macro algae. In order to tap the bioresource, a significant amount of work has been carried out for large scale production of algal biomass. However, work on downstream processing aspects of phycobiliproteins (PBPs) from algae is scarce, especially in case of macroalgae. There are several difficulties in cell wall disruption of both micro and macro algae because of their cell wall structure and compositions. At the same time, there are several challenges in the purification of phycobiliproteins. The current review article focuses on the recent developments in downstream processing of phycobiliproteins (mainly phycocyanins and phycoerythrins) from micro and macroalgae. The current status, the recent advancements and potential technologies (that are under development) are summarised in this review article besides providing future directions for the present research area.

scholarly journals A Metzincin and TIMP-Like Protein Pair of a Phage Origin Sensitize Listeria monocytogenes to Phage Lysins and Other Cell Wall Targeting Agents

2021 ◽  
Vol 9 (6) ◽  
pp. 1323
Author(s):  
Etai Boichis ◽  
Nadejda Sigal ◽  
Ilya Borovok ◽  
Anat A. Herskovits
Keyword(s):  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Mammalian Cells ◽  
Protein Pair ◽  
Growth Conditions ◽  
Wall Structure ◽  
Antibiotic Resistant ◽  
Extracellular Milieu ◽  
Virion Release ◽  
Genes Encoding

Infection of mammalian cells by Listeria monocytogenes (Lm) was shown to be facilitated by its phage elements. In a search for additional phage remnants that play a role in Lm’s lifecycle, we identified a conserved locus containing two XRE regulators and a pair of genes encoding a secreted metzincin protease and a lipoprotein structurally similar to a TIMP-family metzincin inhibitor. We found that the XRE regulators act as a classic CI/Cro regulatory switch that regulates the expression of the metzincin and TIMP-like genes under intracellular growth conditions. We established that when these genes are expressed, their products alter Lm morphology and increase its sensitivity to phage mediated lysis, thereby enhancing virion release. Expression of these proteins also sensitized the bacteria to cell wall targeting compounds, implying that they modulate the cell wall structure. Our data indicate that these effects are mediated by the cleavage of the TIMP-like protein by the metzincin, and its subsequent release to the extracellular milieu. While the importance of this locus to Lm pathogenicity remains unclear, the observation that this phage-associated protein pair act upon the bacterial cell wall may hold promise in the field of antibiotic potentiation to combat antibiotic resistant bacterial pathogens.

scholarly journals Preanesthetic severe postural hypotension following 5-aminolevulinic acid pretreatment in patients for photodynamic diagnosis-assisted urological surgery

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Tohru Shiratori ◽  
Kunihisa Hotta ◽  
Masaaki Satoh ◽  
Chiaki Kiuchi ◽  
Noriyuki Ogawa ◽  
...  
Keyword(s):  
Postural Hypotension ◽  
Aminolevulinic Acid ◽  
Vital Signs ◽  
Photodynamic Diagnosis ◽  
Careful Monitoring ◽  
High Concentration ◽  
Acid Pretreatment ◽  
Case Presentation ◽  
Severe Hypotension ◽  
Prolonged Hypotension

Abstract Background 5-Aminolevulinic acid (5-ALA) is utilized for photodynamic diagnosis-assisted (PDD) surgery. However, it has been associated with vasodilation, hence, occasional hypotension. Case presentation We encountered two patients who had severe postural hypotension following 5-ALA pretreatment prior to an operation. They were scheduled for urological PDD surgery, but upon standing to walk to the operation room, they felt sick because of severe hypotension. One of them underwent the surgery after recovery, but the other surgery was canceled due to a prolonged hypotension that lasted for more than a day. Conclusions Severe postural hypotension may develop as a result of the high concentration of porphyrin precursors, which may affect the nervous system. Severe postural hypotension may be due to 5-ALA-induced autonomic dysfunction as well as vasodilative action of 5-ALA. These observations suggest that in addition to the careful monitoring of patients’ vital signs, standing should be avoided following 5-ALA pretreatment.

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