Evaluating the Effect of Residual Lignin Contents and Fermentation Systems on Bioethanol Production

2021 ◽  
Vol 15 (3) ◽  
pp. 312-322
Author(s):  
Yanzhi You ◽  
Changhe Ding ◽  
Jinlong Li ◽  
Jun Meng ◽  
Xiankun Zhang ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Ethanol Yield ◽  
Lignin Content ◽  
Tween 80 ◽  
Cost Effective ◽  
Bioethanol Production ◽  
Residual Lignin ◽  
Buffer Solution ◽  
Citrate Buffer ◽  
Process Route

Peroxide-acetic acid (Peroxide-HAc) pretreatment is a simplified and cost-effective technology due to its mild conditions without the catalysis of strong acids, which was introduced to treat sugarcane bagasse (SCB) in this paper. Then pretreated SCB was used to produce bioethanol using thermophilic Saccharomyces cerevisiae in deionized water (DW) and sodium citrate buffer solution (SCS) fermentation systems, respectively. Results: showed that peroxide-HAc pretreatment can selectively remove lignin and change morphological structures, thus positively increasing saccharification and fermentation efficiency downstream. SCB pretreated at 100 °C obtained the lowest residual lignin content of 2.88% and achieved the highest ethanol yield of 92.10% (0.45 g/g-biomass) in DW system. In particular, SCS can decrease the residual sugars content of pretreated SCB during simultaneous saccharification and co-fermentation (SSCF) process. The addition of Tween 80 improved SSCF of SCB pretreated at 80 °C likely because Tween 80 can block residual lignin adsorption with enzymes. The concentration of acetic acid and glycerol byproducts from SCB pretreated at 80 °C can be decreased by SCS and DW systems, respectively, comparing to SCS and DW systems with additing Tween 80. This study provided a systematic process route for the bioethanol production by mild pretreatment method.

scholarly journals Study of Regularities and Optimization of the Process of Fir Wood Peroxide Delignification in the Medium of “Acetic Acid – Water” in the Presence of Sulfuric Acid Catalyst

2019 ◽  
pp. 590-603
Author(s):  
Olga V. Yatsenkova ◽  
Andrei M. Skripnikov ◽  
Boris N. Kuznetsov
Keyword(s):  
Acetic Acid ◽  
Lignin Content ◽  
Reaction Medium ◽  
Acid Catalyst ◽  
Acid Water ◽  
High Yield ◽  
Process Conditions ◽  
Residual Lignin ◽  
Acetic Acid Water ◽  
Peroxide Delignification

The work describes a one-stage method of cellulose obtaining from fir wood based on peroxide delignification of wood under mild conditions (100 °C, atmospheric pressure) in the presence of acetic acid, water and catalyst of 2% wt. H2SO4. The possibility of obtaining cellulose with a residual lignin content <1% wt. at a low concentration of hydrogen peroxide (3% wt.) in the reaction medium was established. The optimal concentrations of reagents (Н2О2 – 3% wt., CH3COOH – 38.9% wt.) and the duration of the process (4 h) were determined by experimental and calculation methods. This conditions provide a high yield of cellulose product (≥45% wt.) with a low content of residual lignin (<1% wt.). The composition and structure of fir cellulose was studied by chemical analysis and by FTIR and SEM methods. The cellulosic product which was obtained in optimal process conditions is high-quality cellulose

scholarly journals CELLULOSIC BIOETHANOL PRODUCTION FROM ULVA LACTUCA MACROALGAE

2021 ◽  
Vol 55 (5-6) ◽  
pp. 629-635
Author(s):  
AMINA ALLOUACHE ◽  
AZIZA MAJDA ◽  
AHMED ZAID TOUDERT ◽  
ABDELTIF AMRANE ◽  
MERCEDES BALLESTEROS
Keyword(s):  
Enzymatic Hydrolysis ◽  
Fossil Fuels ◽  
Ethanol Yield ◽  
Lignin Content ◽  
Arable Land ◽  
Ulva Lactuca ◽  
Marine Macroalgae ◽  
Bioethanol Production ◽  
Acid Pretreatment ◽  
Total Glucose

Nowadays, the use of biofuels has become an unavoidable solution to the depletion of fossil fuels and global warming. The controversy over the use of food crops for the production of the first-generation biofuels and deforestation caused by the second-generation ones has forced the transition to the third generation of biofuels, which avoids the use of arable land and edible products, and does not threaten biodiversity. This generation is based on the marine and freshwater biomass, which has the advantages of being abundant or even invasive, easy to cultivate and having a good energetic potential. Bioethanol production from Ulva lactuca, a local marine macroalgae collected from the west coast of Algiers, was examined in this study. Ulva lactuca showed a good energetic potential due to its carbohydrate-rich content: 9.57% of cellulose, 6.9% of hemicellulose and low lignin content of 5.11%. Ethanol was produced following the separate hydrolysis and fermentation process (SHF), preceded by a thermal acid pretreatment at 120 °C during 15 min. Enzymatic hydrolysis was performed using a commercial cellulase (Celluclast 1.5 L), which saccharified the cellulose contained in the green seaweed, releasing about 85.01% of the total glucose, corresponding to 7.21 g/L after 96 h of enzymatic hydrolysis at pH 5 and 45 °C. About 3.52 g/L of ethanol was produced after 48 h of fermentation using Saccharomyces cerevisiae at 30 °C and pH 5, leading to a high ethanol yield of 0.41 g of ethanol/g of glucose.

scholarly journals The Improvement of Bioethanol Production by Pentose-Fermenting Yeasts Isolated from Herbal Preparations, the Gut of Dung Beetles, and Marula Wine

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Mahlatse Ellias Moremi ◽  
Elbert Lukas Jansen Van Rensburg ◽  
Daniël Coenrad La Grange
Keyword(s):  
Acetic Acid ◽  
Carbon Source ◽  
Parental Strain ◽  
Ethanol Yield ◽  
Dung Beetles ◽  
Adaptation Process ◽  
Bioethanol Production ◽  
Herbal Preparations ◽  
Efficient Conversion ◽  
Pentose Sugars

Efficient conversion of pentose sugars to ethanol is important for an economically viable lignocellulosic bioethanol process. Ten yeasts fermenting both D-xylose and L-arabinose were subjected to an adaptation process with L-arabinose as carbon source in a medium containing acetic acid. Four Meyerozyma caribbica-adapted strains were able to ferment L-arabinose to ethanol in the presence of 3 g/L acetic acid at 35°C. Meyerozyma caribbica Mu 2.2f fermented L-arabinose to produce 3.0 g/L ethanol compared to the parental strain with 1.0 g/L ethanol in the absence of acetic acid. The adapted M. caribbica Mu 2.2f strain produced 3.6 and 0.8 g/L ethanol on L-arabinose and D-xylose, respectively, in the presence of acetic acid while the parental strain failed to grow. In a bioreactor, the adapted M. caribbica Mu 2.2f strain produced 5.7 g/L ethanol in the presence of 3 g/L acetic acid with an ethanol yield and productivity of 0.338 g/g and 0.158 g/L/h, respectively, at a KLa value of 3.3 h−1. The adapted strain produced 26.7 g/L L-arabitol with a yield of 0.900 g/g at a KLa value of 4.9 h−1.

scholarly journals Chemical Pretreatments on Residual Cocoa Pod Shell Biomass for Bioethanol Production

Bionatura ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 1490-1500
Author(s):  
Jose F. Alvarez-Barreto ◽  
Fernando Larrea ◽  
Maria C. Pinos C ◽  
Jose Benalcázar ◽  
Daniela Oña ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Reducing Sugars ◽  
Ethanol Yield ◽  
Lignin Content ◽  
Reducing Sugar ◽  
Sugar Concentration ◽  
Biomass Composition ◽  
Future Research ◽  
Bioethanol Production ◽  
Acid Pretreatment

Cocoa pod shell is an essential agricultural residue in Ecuador, and this study addressed its potential valorization for bioethanol production. For this, three types of pretreatments, acid, alkaline, and autohydrolysis, were applied to pod shells from two different cocoa types, national and CCN-51. to remove the lignin. Untreated and treated biomasses were characterized by composition, thermal stability, Fourier transformed infrared spectroscopy (FITR), and scanning electron microscopy (SEM). The treated biomass was then enzymatically hydrolyzed with cellulase. Reducing sugars were quantified after pretreatments and enzymatic hydrolysis, and the pretreatment liquors and the enzymatic hydrolysates were subjected to alcoholic fermentation with Saccharomyces cerevisiae. There were substantial differences in composition between both biomasses, particularly in lignin content, with national cocoa having the lowest values. All pretreatment conditions had significant effects on biomass composition, structure, and thermal properties. After alkaline pretreatment, the biomass presented the highest cellulose and lowest lignin contents, resulting in the highest reducing sugar concentration in the pretreatment liquor. The highest lignin content was found after the acid pretreatment, which resulted in low, reducing sugar concentrations. Autohydrolysis produced similar results as the acid pretreatment; however, it resulted in the highest sugar concentration after enzymatic hydrolysis, while the acid-treated sample had negligible levels. After fermentation, there were no differences in productivity among the pretreatment liquors, but autohydrolysis had the largest ethanol yield. In the hydrolysates, it was also autohydrolysis that resulted in higher productivity and yield. Thus, there is an indication of the formation of inhibitors, both enzymatic activity and ethanol production, in the acid and alkaline pretreatments, and this should be tackled in future research. Nonetheless, given the crucial changes observed in biomass, we believe that cocoa pod shell pretreatment has potential for the generation of reducing sugars that could be further used in different bioprocesses, nor only bioethanol production.

scholarly journals Saccharomyces cerevisiae Fermentation of 28 Barley and 12 Oat Cultivars

Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 59
Author(s):  
Timothy J. Tse ◽  
Daniel J. Wiens ◽  
Jianheng Shen ◽  
Aaron D. Beattie ◽  
Martin J. T. Reaney
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Succinic Acid ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Cereal Crops ◽  
Fermentation Products ◽  
Barley Cultivars ◽  
Oat Cultivars

As barley and oat production have recently increased in Canada, it has become prudent to investigate these cereal crops as potential feedstocks for alcoholic fermentation. Ethanol and other coproduct yields can vary substantially among fermented feedstocks, which currently consist primarily of wheat and corn. In this study, the liquified mash of milled grains from 28 barley (hulled and hull-less) and 12 oat cultivars were fermented with Saccharomyces cerevisiae to determine concentrations of fermentation products (ethanol, isopropanol, acetic acid, lactic acid, succinic acid, α-glycerylphosphorylcholine (α-GPC), and glycerol). On average, the fermentation of barley produced significantly higher amounts of ethanol, isopropanol, acetic acid, succinic acid, α-GPC, and glycerol than that of oats. The best performing barley cultivars were able to produce up to 78.48 g/L (CDC Clear) ethanol and 1.81 g/L α-GPC (CDC Cowboy). Furthermore, the presence of milled hulls did not impact ethanol yield amongst barley cultivars. Due to its superior ethanol yield compared to oats, barley is a suitable feedstock for ethanol production. In addition, the accumulation of α-GPC could add considerable value to the fermentation of these cereal crops.

scholarly journals Aliphatic extractive effects on acetic acid catalysis of typical agricultural residues to xylo-oligosaccharide and enzymatic hydrolyzability of cellulose

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jianming Guo ◽  
Kaixuan Huang ◽  
Rou Cao ◽  
Junhua Zhang ◽  
Yong Xu
Keyword(s):  
Acetic Acid ◽  
Acid Catalysis ◽  
Cost Effective ◽  
Economic Benefits ◽  
Ethanol Extraction ◽  
Minimal Impact ◽  
Aliphatic Compounds ◽  
Organic Solvent Extraction ◽  
Promising Application ◽  
Poplar Sawdust

Abstract Background Xylo-oligosaccharide is the spotlight of functional sugar that improves the economic benefits of lignocellulose biorefinery. Acetic acid acidolysis technology provides a promising application for xylo-oligosaccharide commercial production, but it is restricted by the aliphatic (wax-like) compounds, which cover the outer and inner surfaces of plants. Results We removed aliphatic compounds by extraction with two organic solvents. The benzene–ethanol extraction increased the yield of acidolyzed xylo-oligosaccharides of corncob, sugarcane bagasse, wheat straw, and poplar sawdust by 14.79, 21.05, 16.68, and 7.26% while ethanol extraction increased it by 11.88, 17.43, 1.26, and 13.64%, respectively. Conclusion The single ethanol extraction was safer, more environmentally friendly, and more cost-effective than benzene–ethanol solvent. In short, organic solvent extraction provided a promising auxiliary method for the selective acidolysis of herbaceous xylan to xylo-oligosaccharides, while it had minimal impact on woody poplar.

scholarly journals Antigen retrieval technique utilizing citrate buffer or urea solution for immunohistochemical demonstration of androgen receptor in formalin-fixed paraffin sections.

1993 ◽  
Vol 41 (11) ◽  
pp. 1599-1604 ◽  
Author(s):  
S R Shi ◽  
B Chaiwun ◽  
L Young ◽  
R J Cote ◽  
C R Taylor
Keyword(s):  
Androgen Receptor ◽  
Enzymatic Digestion ◽  
Antigen Retrieval ◽  
Urea Solution ◽  
Paraffin Sections ◽  
Buffer Solution ◽  
Solution Ph ◽  
Citrate Buffer ◽  
Formalin Fixed Paraffin ◽  
Formalin Fixed

We developed a staining protocol for demonstration of androgen receptor (AR) in formalin-fixed, paraffin-embedded tissue sections. The method is based on the antigen retrieval microwave (MW) heating technique. Results are compared with different types of enzyme digestion pre-treatments. The strongest immunostaining signal and clearest background were obtained by MW heating of dewaxed paraffin sections in 5% urea or citrate buffer solution (pH 6); pure distilled water gave less consistent results. Enzymatic digestion with pepsin (0.05% in 2 N HCl) for 30 min at room temperature, or trypsin followed by pronase, or pronase digestion alone, also produced enhanced staining of AR in some cases, but there was more nonspecific background, and specific reactivity was less intense. The antigen retrieval MW method can be used to demonstrate AR epitope in prostate tissue after fixation in formalin for as long as 7 days. AR immunolocalization was also compared in frozen and paraffin sections processed from the same specimen of prostate carcinoma tissue and was found to be qualitatively and quantitatively similar. This study also provided new information concerning the basic principles of the antigen retrieval MW method that may be helpful in further development of this technique.

scholarly journals Recombinant Diploid Saccharomyces cerevisiae Strain Development for Rapid Glucose and Xylose Co-Fermentation

Fermentation ◽  
2018 ◽  
Vol 4 (3) ◽  
pp. 59 ◽  
Author(s):  
Tingting Liu ◽  
Shuangcheng Huang ◽  
Anli Geng
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Xylose Isomerase ◽  
Cost Effective ◽  
Xylose Utilization ◽  
Yeast Strains ◽  
Multiple Copies ◽  
Biomass Sugars ◽  
Sugar Conversion

Cost-effective production of cellulosic ethanol requires robust microorganisms for rapid co-fermentation of glucose and xylose. This study aims to develop a recombinant diploid xylose-fermenting Saccharomyces cerevisiae strain for efficient conversion of lignocellulosic biomass sugars to ethanol. Episomal plasmids harboring codon-optimized Piromyces sp. E2 xylose isomerase (PirXylA) and Orpinomyces sp. ukk1 xylose (OrpXylA) genes were constructed and transformed into S. cerevisiae. The strain harboring plasmids with tandem PirXylA was favorable for xylose utilization when xylose was used as the sole carbon source, while the strain harboring plasmids with tandem OrpXylA was beneficial for glucose and xylose cofermentation. PirXylA and OrpXylA genes were also individually integrated into the genome of yeast strains in multiple copies. Such integration was beneficial for xylose alcoholic fermentation. The respiration-deficient strain carrying episomal or integrated OrpXylA genes exhibited the best performance for glucose and xylose co-fermentation. This was partly attributed to the high expression levels and activities of xylose isomerase. Mating a respiration-efficient strain carrying the integrated PirXylA gene with a respiration-deficient strain harboring integrated OrpXylA generated a diploid recombinant xylose-fermenting yeast strain STXQ with enhanced cell growth and xylose fermentation. Co-fermentation of 162 g L−1 glucose and 95 g L−1 xylose generated 120.6 g L−1 ethanol in 23 h, with sugar conversion higher than 99%, ethanol yield of 0.47 g g−1, and ethanol productivity of 5.26 g L−1·h−1.

scholarly journals Efficient Production of Acetic Acid from Nipa (Nypa fruticans) Sap by Moorella thermoacetica (f. Clostridium thermoaceticum)

2019 ◽  
Author(s):  
Dung Van Nguyen ◽  
Pinthep Sethapokin ◽  
Harifara Rabemanolontsoa ◽  
Eiji Minami ◽  
Haruo Kawamoto ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Oxalic Acid ◽  
Acid Catalyst ◽  
Cost Effective ◽  
Efficient Production ◽  
Acid Fermentation ◽  
Acid Yield ◽  
Moorella Thermoacetica ◽  
Nypa Fruticans ◽  
Hydrolysis Of

To valorize the underutilized nipa sap composed mainly of sucrose, glucose and fructose, acetic acid fermentation by Moorella thermoacetica was explored. Given that M. thermoacetica cannot directly metabolize sucrose, we evaluated various catalysts for the hydrolysis of this material. Oxalic acid and invertase exhibited high levels of activity towards the hydrolysis of the sucrose in nipa sap to glucose and fructose. Although these two methods consumed similar levels of energy for the hydrolysis of sucrose, oxalic acid was found to be more cost-effective. Nipa saps hydrolyzed by these two catalysts were also fermented by M. thermoacetica. The results revealed that the two hydrolyzed sap mixtures gave 10.0 g/L of acetic acid from the 10.2 g/L of substrate sugars in nipa sap. Notably, the results showed that the oxalic acid catalyst was also fermented to acetic acid, which avoided the need to remove the catalyst from the product stream. Taken together, these results show that oxalic acid hydrolysis is superior to enzymatic hydrolysis for the pretreatment of nipa sap. The acetic acid yield achieved in this study corresponds to a conversion efficiency of 98%, which is about 3.6 times higher than that achieved using the traditional methods. The process developed in this study therefore has high potential as a green biorefinery process for the efficient conversion of sucrose-containing nipa sap to bio-derived acetic acid.

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