Nitric Acid Pretreatment of Jerusalem Artichoke Stalks for Enzymatic Saccharification and Bioethanol Production

This paper evaluated the effectiveness of nitric acid pretreatment on the hydrolysis and subsequent fermentation of Jerusalem artichoke stalks (JAS). Jerusalem artichoke is considered a potential candidate for producing bioethanol due to its low soil and climate requirements, and high biomass yield. However, its stalks have a complexed lignocellulosic structure, so appropriate pretreatment is necessary prior to enzymatic hydrolysis, to enhance the amount of sugar that can be obtained. Nitric acid is a promising catalyst for the pretreatment of lignocellulosic biomass due to the high efficiency with which it removes hemicelluloses. Nitric acid was found to be the most effective catalyst of JAS biomass. A higher concentration of glucose and ethanol was achieved after hydrolysis and fermentation of 5% (w/v) HNO3-pretreated JAS, leading to 38.5 g/L of glucose after saccharification, which corresponds to 89% of theoretical enzymatic hydrolysis yield, and 9.5 g/L of ethanol. However, after fermentation there was still a significant amount of glucose in the medium. In comparison to more commonly used acids (H2SO4 and HCl) and alkalis (NaOH and KOH), glucose yield (% of theoretical yield) was approximately 47–74% higher with HNO3. The fermentation of 5% nitric-acid pretreated hydrolysates with the absence of solid residues, led to an increase in ethanol yield by almost 30%, reaching 77–82% of theoretical yield.

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

Processes ◽

10.3390/pr9081360 ◽

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.

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Evaluation of the Interactive Effect Pretreatment Parameters via Three Types of Microwave-Assisted Pretreatment and Enzymatic Hydrolysis on Sugar Yield

Processes ◽

10.3390/pr8070787 ◽

2020 ◽

Vol 8 (7) ◽

pp. 787 ◽

Cited By ~ 1

Author(s):

Saleem Ethaib ◽

Rozita Omar ◽

Mustapa Kamal Siti Mazlina ◽

Awang Biak Dayang Radiah

Keyword(s):

Response Surface Methodology ◽

Enzymatic Hydrolysis ◽

Interactive Effect ◽

Reducing Sugar ◽

Sugar Yield ◽

Solid Loading ◽

Acid Pretreatment ◽

Glucose Yield ◽

Sago Palm ◽

Microwave Assisted

This study aims to evaluate the sugar yield from enzymatic hydrolysis and the interactive effect pretreatment parameters of microwave-assisted pretreatment on glucose and xylose. Three types of microwave-assisted pretreatments of sago palm bark (SPB) were conducted for enzymatic hydrolysis, namely: microwave-sulphuric acid pretreatment (MSA), microwave-sodium hydroxide pretreatment (MSH), and microwave-sodium bicarbonate (MSB). The experimental design was done using a response surface methodology (RSM) and Box–Behenken Design (BBD). The pretreatment parameters ranged from 5–15% solid loading (SL), 5–15 min of exposure time (ET), and 80–800 W of microwave power (MP). The results indicated that the maximum total reducing sugar was 386 mg/g, obtained by MSA pretreatment. The results also illustrated that the higher glucose yield, 44.3 mg/g, was found using MSH pretreatment, while the higher xylose yield, 43.1 mg/g, resulted from MSA pretreatment. The pretreatment parameters MP, ET, and SL showed different patterns of influence on glucose and xylose yield via enzymatic hydrolysis for MSA, MSH, and MSB pretreatments. The analyses of the interactive effect of the pretreatment parameters MP, ET, and SL on the glucose yield from SPB showed that it increased with the high MP and longer ET, but this was limited by low SL values. However, the analysis of the interactive effect of the pretreatment parameters on xylose yields revealed that MP had the most influence on the xylose yield for MSA, MSH, and MSB pretreatments.

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Comparison of Bacterial and Yeast Ethanol Fermentation Yield from Rice Straw

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.347-353.2541 ◽

2011 ◽

Vol 347-353 ◽

pp. 2541-2544

Author(s):

Benjarat Laobussararak ◽

Warawut Chulalaksananukul ◽

Orathai Chavalparit

Keyword(s):

Saccharomyces Cerevisiae ◽

Enzymatic Hydrolysis ◽

Rice Straw ◽

Zymomonas Mobilis ◽

Ethanol Yield ◽

Sugar Content ◽

Alkali Pretreatment ◽

Yeast Saccharomyces Cerevisiae ◽

Pretreatment Condition ◽

Theoretical Yield

This study was to investigate the fermentation of rice straw using various microorganisms, i.e., the bacterium Zymomonas mobilis, a distillery yeast Saccharomyces cerevisiae and a co-culture of Zymomonas mobilis and Saccharomyces cerevisiae. Rice straw was pretreated with alkaline and followed by enzymatic hydrolysis using cellulase before fermentation by the bacterium and a distillery yeast. Results show that alkali pretreatment is appropriate for rice straw since this pretreatment condition can produce the maximum cellulose of 88.96% and reducing sugar content of 9.18 g/l. Furthermore, the ethanol yield after enzymatic hydrolysis (expressed as % theoretical yield) was 15.94-19.73% for the bacterium, 20.48-35.70% for yeast and 21.56-29.89% for co-culture. Therefore, the distillery yeast was a suitable microorganism for ethanol production from rice straw.

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Enhanced Enzymatic Saccharification of Mixed Sawdust Wastes: Comparison of SPORL, Dilute Acid, Formic Acid, and Ethanol Organosolv Pretreatments

Journal of the Mexican Chemical Society ◽

10.29356/jmcs.v65i3.1427 ◽

2021 ◽

Vol 65 (3) ◽

Author(s):

Yuan Liang ◽

Yanbo Yin ◽

Haifeng Zhou ◽

Yuanyu Tian

Keyword(s):

Formic Acid ◽

Enzymatic Saccharification ◽

Fiber Surface ◽

Dilute Acid Pretreatment ◽

Dilute Acid ◽

Acid Pretreatment ◽

Glucose Yield ◽

Hemicellulose Removal ◽

Ethanol Pretreatment ◽

Hydrolysis Of

Abstract. Utilization of the huge quantity of sawdust wastes is urgent. In this study, SPORL, dilute acid pretreatment (DA), formic acid pretreatment (FA), ethanol pretreatment (EtOH/H2O), and sulfuric acid catalyzed ethanol pretreatment (EtOH/H2O/H2SO4), on improving enzymatic hydrolysis of mixed sawdust wastes were comprehensively compared. EtOH/H2O/H2SO4 was the most effective pretreatment in lignin removal from sawdust fiber cell wall, while FA was much more effective in hemicellulose removal. After the pretreatments, the crystallinity of cellulose increased because of the removal of amorphous hemicellulose and lignin. Moreover, the fiber surface became coarse and porous, especially after EtOH/H2O/H2SO4, the structure was destroyed into fragments, which enhanced the cellulase accessibility of cellulose. Therefore, the glucose yield of EtOH/H2O/H2SO4 pretreated substrate was highest among these five pretreatments, achieved at 91.4% with a cellulase loading of only 10 FPU/g glucan. Resumen. Es urgente aprovechar la gran cantidad de residuos de aserrín. En este estudio, SPORL, pretratamiento con ácido diluido (DA), pretratamiento con ácido fórmico (FA), pretratamiento con etanol (EtOH/H2O) y pretratamiento con etanol catalizado con ácido sulfúrico (EtOH/H2O/H2SO4), sobre la mejora de la hidrólisis enzimática de residuos de aserrín mezclado fueron comparados de manera integral. EtOH/H2O/H2SO4 fue el pretratamiento más eficaz para eliminar la lignina de la pared celular de la fibra de aserrín, mientras que el FA fue mucho más eficaz para eliminar la hemicelulosa. Después de los pretratamientos, la cristalinidad de la celulosa aumentó debido a la eliminación de hemicelulosa amorfa y lignina. Además, la superficie de la fibra se volvió gruesa y porosa, especialmente después de EtOH/H2O/H2SO4, la estructura se destruyó en fragmentos, lo que mejoró la accesibilidad de celulasa de la celulosa. Por lo tanto, el rendimiento de glucosa del sustrato pretratado con EtOH/H2O/H2SO4 fue el más alto entre estos cinco pretratamientos, alcanzado al 91,4% con una carga de celulasa de solo 10 FPU / g de glucano.

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CELLULOSIC BIOETHANOL PRODUCTION FROM ULVA LACTUCA MACROALGAE

Cellulose Chemistry and Technology ◽

10.35812/cellulosechemtechnol.2021.55.51 ◽

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.

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

Biotechnology for Biofuels ◽

10.1186/s13068-021-01999-7 ◽

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.

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Effect of lignin content on enzymatic hydrolysis of furfural residues

BioResources ◽

10.15376/biores.6.1.317-328 ◽

2010 ◽

Vol 6 (1) ◽

pp. 317-328 ◽

Cited By ~ 4

Author(s):

Ran Sun ◽

Xianliang Song ◽

Runcang Sun ◽

Jianxin Jiang

Keyword(s):

Enzymatic Hydrolysis ◽

Lignin Content ◽

Enzymatic Saccharification ◽

Cost Effective ◽

Raw Material ◽

Enzyme Loading ◽

Glucose Yield ◽

Lignin Removal ◽

Furfural Residues ◽

Enzyme Dosage

The enzymatic saccharification of pretreated furfural residues with different lignin content was studied to verify the effect of lignin removal in the hydrolysis process. The results showed that the glucose yield was improved by increasing the lignin removal. A maximum glucose yield of 96.8% was obtained when the residue with a lignin removal of 51.4% was hydrolyzed for 108 h at an enzyme loading of 25 FPU/g cellulose. However, further lignin removal did not increase the hydrolysis. The effect of enzyme loading on the enzymatic hydrolysis was also explored in this work. It was concluded that a high glucose yield of 90% was achieved when the enzyme dosage was reduced from 25 to 15 FPU/g cellulose, which was cost-effective for the sugar and ethanol production. The structures of raw material and delignified samples were further characterized by XRD and scanning electron microscopy (SEM).

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Enzymatic Saccharification and Ethanol Fermentation of Reed Pretreated with Liquid Hot Water

Journal of Biomedicine and Biotechnology ◽

10.1155/2012/276278 ◽

2012 ◽

Vol 2012 ◽

pp. 1-9 ◽

Cited By ~ 10

Author(s):

Jie Lu ◽

XueZhi Li ◽

Jian Zhao ◽

Yinbo Qu

Keyword(s):

Enzymatic Hydrolysis ◽

Enzymatic Saccharification ◽

Hot Water ◽

Ethanol Conversion ◽

Optimum Conditions ◽

Enzymatic Digestibility ◽

Material Source ◽

Theoretical Yield ◽

Liquid Hot Water ◽

Filter Paper Unit

Reed is a widespread-growing, inexpensive, and readily available lignocellulosic material source in northeast China. The objective of this study is to evaluate the liquid hot water (LHW) pretreatment efficiency of reed based on the enzymatic digestibility and ethanol fermentability of water-insoluble solids (WISs) from reed after the LHW pretreatment. Several variables in the LHW pretreatment and enzymatic hydrolysis process were optimized. The conversion of glucan to glucose and glucose concentrations are considered as response variables in different conditions. The optimum conditions for the LHW pretreatment of reed area temperature of 180°C for 20min and a solid-to-liquid ratio of 1 : 10. These optimum conditions for the LHW pretreatment of reed resulted in a cellulose conversion rate of 82.59% in the subsequent enzymatic hydrolysis at 50°C for 72 h with a cellulase loading of 30 filter paper unit per gram of oven-dried WIS. Increasing the pretreatment temperature resulted in a higher enzymatic digestibility of the WIS from reed. Separate hydrolysis and fermentation of WIS showed that the conversion of glucan to ethanol reached 99.5% of the theoretical yield. The LHW pretreatment of reed is a suitable method to acquire a high recovery of fermentable sugars and high ethanol conversion yield.

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Evaluation of commercial cellulase preparations for the efficient hydrolysis of hydrothermally pretreated empty fruit bunches

BioResources ◽

10.15376/biores.12.4.7834-7840 ◽

2017 ◽

Vol 12 (4) ◽

pp. 7834-7840 ◽

Cited By ~ 4

Author(s):

Jungwoo Yang ◽

Ji Eun Kim ◽

Jae Kyun Kim ◽

Sung ho Lee ◽

Ju-Hyun Yu ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Lignocellulosic Biomass ◽

Enzymatic Saccharification ◽

Glucose Yield ◽

Pretreatment Method ◽

Biomass Feedstocks ◽

Empty Fruit Bunches ◽

Hydrolysis Of

The performance of cellulase in the enzymatic saccharification of lignocellulose depends on the characteristics of lignocellulosic biomass feedstocks and the pretreatment method used. Efficient hydrolysis of specifically pretreated lignocellulose necessitates the knowledge of the characteristics of the optimal commercial cellulases. In this study, commercial cellulase preparations (Accellerase™ 1000, Accellerase® 1500, and Spezyme® CP from DuPont and Cellic® CTec2 from Novozymes) were evaluated for their hydrolysis efficiency of hydrothermally pretreated empty fruit bunches (EFBs). The highest glucose yields of 91.3% and 84.7% were achieved for 30 FPU of Cellic® CTec2/g glucan with and without Cellic® HTec2, respectively. Of the four cellulases tested, Cellic® CTec2, which showed the highest cellobiohydrolase, xylanase, and β-glucosidase activities, showed the highest glucose yield in the enzymatic hydrolysis of hydrothermally pretreated EFBs. The results of this study are valuable for those who plan to enzymatically hydrolyze hydrothermally pretreated EFBs.

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Bioethanol Production From Pineapple Wastes

Journal of Food Research ◽

10.5539/jfr.v3n4p60 ◽

2014 ◽

Vol 3 (4) ◽

pp. 60 ◽

Cited By ~ 12

Author(s):

Alessia Tropea ◽

David Wilson ◽

Loredana G. La Torre ◽

Rosario B. Lo Curto ◽

Peter Saugman ◽

...

Keyword(s):

Plant Cell ◽

Cell Walls ◽

Simultaneous Saccharification And Fermentation ◽

Ethanol Yield ◽

Enzymatic Saccharification ◽

Plant Cell Walls ◽

Theoretical Yield ◽

Cellulosic Sugars ◽

Separate Hydrolysis And Fermentation ◽

Simultaneous Saccharification

There is great interest in producing bioethanol from biomass and there is much emphasis on exploiting lignocellulose sources, from crop wastes through to energy-rich crops. Some waste streams, however, contain both cellulosic and non-cellulosic sugars. These include wastes from pineapple processing. Pineapple wastes are produced in large amounts throughout the world by canning industries. These wastes are rich in intracellular sugars and plant cell walls which are composed mainly of cellulose, pectic substances and hemicelluloses. The purpose of this study was to investigate the potential to transform such residues into ethanol after enzymatic saccharification of plant cell walls, and fermentation of the resulting simple sugars using the Saccharomyces cerevisiae NCYC 2826 strain. Three different fermentation modes, direct fermentation, separate hydrolysis and fermentation, and simultaneous saccharification and fermentation of the biomass were tested and compared. The results show that the main sugars obtained from pineapple waste were: glucose, uronic acid, xylose, galactose, arabinose and mannose. The highest ethanol yield was achieved after 30 hours of simultaneous saccharification and fermentation, and reached up to 3.9% (v/v), corresponding to the 96% of the theoretical yield.

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