scholarly journals Eco-friendly consolidated process for co-production of xylooligosaccharides and fermentable sugars using self-providing xylonic acid as key pretreatment catalyst

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Xin Zhou ◽  
Yong Xu
Keyword(s):  
Value Added ◽  
Glucose Production ◽  
Gluconobacter Oxydans ◽  
Fermentable Sugars ◽  
Acid Pretreatment ◽  
Cellulose Conversion ◽  
Xylonic Acid ◽  
Balance Analysis ◽  
High Yields ◽  
Hydrolysis Of

Abstract Background Obtaining high-value products from lignocellulosic biomass is central for the realization of industrial biorefinery. Acid pretreatment has been reported to yield xylooligosaccharides (XOS) and improve enzymatic hydrolysis. Moreover, xylose, an inevitable byproduct, can be upgraded to xylonic acid (XA). The aim of this study was to valorize sugarcane bagasse (SB) by starting with XA pretreatment for XOS and glucose production within a multi-product biorefinery framework. Results SB was primarily subjected to XA pretreatment to maximize the XOS yield by the response surface method (RSM). A maximum XOS yield of 44.5% was achieved by acid pretreatment using 0.64 M XA for 42 min at 154 °C. Furthermore, XA pretreatment can efficiently improve enzymatic digestibility, and achieved a 90.8% cellulose conversion. In addition, xylose, the inevitable byproduct of the acid-hydrolysis of xylan, can be completely converted to XA via bio-oxidation of Gluconobacter oxydans (G. oxydans). Subsequently, XA and XOS can be simultaneously separated by electrodialysis. Conclusions XA pretreatment was explored and exhibited a promising ability to depolymerize xylan into XOS. Mass balance analysis showed that the maximum XOS and fermentable sugars yields reached 10.5 g and 30.9 g per 100 g raw SB, respectively. In summary, by concurrently producing XOS and fermentable sugars with high yields, SB was thus valorized as a promising feedstock of lignocellulosic biorefinery for value-added products.

scholarly journals Defining the Frontiers of Synergism between Cellulolytic Enzymes for Improved Hydrolysis of Lignocellulosic Feedstocks

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1343
Author(s):  
Mpho S. Mafa ◽  
Brett I. Pletschke ◽  
Samkelo Malgas
Keyword(s):  
Value Added ◽  
Product Yield ◽  
Cellulose Hydrolysis ◽  
Cellulolytic Enzymes ◽  
Cellulolytic Enzyme ◽  
Key Factors ◽  
Cellulose Conversion ◽  
Lignocellulosic Feedstocks ◽  
Polysaccharide Monooxygenases ◽  
Hydrolysis Of

Lignocellulose has economic potential as a bio-resource for the production of value-added products (VAPs) and biofuels. The commercialization of biofuels and VAPs requires efficient enzyme cocktail activities that can lower their costs. However, the basis of the synergism between enzymes that compose cellulolytic enzyme cocktails for depolymerizing lignocellulose is not understood. This review aims to address the degree of synergism (DS) thresholds between the cellulolytic enzymes and how this can be used in the formulation of effective cellulolytic enzyme cocktails. DS is a powerful tool that distinguishes between enzymes’ synergism and anti-synergism during the hydrolysis of biomass. It has been established that cellulases, or cellulases and lytic polysaccharide monooxygenases (LPMOs), always synergize during cellulose hydrolysis. However, recent evidence suggests that this is not always the case, as synergism depends on the specific mechanism of action of each enzyme in the combination. Additionally, expansins, nonenzymatic proteins responsible for loosening cell wall fibers, seem to also synergize with cellulases during biomass depolymerization. This review highlighted the following four key factors linked to DS: (1) a DS threshold at which the enzymes synergize and produce a higher product yield than their theoretical sum, (2) a DS threshold at which the enzymes display synergism, but not a higher product yield, (3) a DS threshold at which enzymes do not synergize, and (4) a DS threshold that displays anti-synergy. This review deconvolutes the DS concept for cellulolytic enzymes, to postulate an experimental design approach for achieving higher synergism and cellulose conversion yields.

scholarly journals Hydrolysis of microcrystalline cellulose isolated from waste seeds of Leucaena leucocephala for glucose production

2019 ◽  
Vol 15 (2) ◽  
pp. 200-205
Author(s):  
Maryam Husin ◽  
Nurnadiah Rahim ◽  
Mohd Radzi Ahmad ◽  
Ahmad Zafir Romli ◽  
Zul Ilham
Keyword(s):  
Microcrystalline Cellulose ◽  
Leucaena Leucocephala ◽  
Acid Treatment ◽  
Value Added ◽  
Glucose Production ◽  
Sugar Composition ◽  
Sulfuric Acid Method ◽  
Percentage Conversion ◽  
Hydrolysis Of ◽  
Phenol Sulfuric Acid

The waste seeds of Leucaena leucocephala (LLS) used in this study were unused residues obtained after oil and polysaccharides extraction. The microcrystalline cellulose (MCC) was isolated from LLS by acid treatment. MCC produced was, then, further converted to glucose by using sulphuric acid at 121 °C by varying the acid concentration and reaction time. The sugar composition was analyzed by using the phenol-sulfuric acid method and pre-column derivatization HPLC technique. The yield of glucose ranging from 70–85% could be obtained from MCC hydrolyzates, depending on the hydrolysis factors, which corresponding to around 57-75% of the percentage conversion of MCC to glucose.Cellulose isolated from LLS was, therefore, potentially suitable to be utilized in liquid biofuels and other value-added chemicals such as bioethanol, 5-hydroxymethylfurfural(HMF), and levulinic acid.

Hydrolysis of Lignocellulosics into Fermentable Sugars for Cellulosic Ethanol Production: An Overview

2012 ◽  
Vol 538-541 ◽  
pp. 2401-2404
Author(s):  
Jun Ping Zhuang ◽  
Xue Ping Li ◽  
Ying Liu
Keyword(s):  
Cellulosic Ethanol ◽  
Hot Water ◽  
Fermentable Sugars ◽  
Future Research ◽  
Water Pretreatment ◽  
Hydrolysis Of Cellulose ◽  
Great Pressure ◽  
High Yields ◽  
Hot Water Pretreatment ◽  
Hydrolysis Of

Facing great pressure of economic growth and energy crisis, China has paid more attention to the renewable energy and cellulosic ethanol has received increasing attention in recent years. The key from lignocelluloses to bioethanol is how to produce fermentable sugars effectively by hydrolysis of cellulose. Chemical, biological pretreatment and hot water pretreatment are considered as three important techniques for high yields of fermentable sugars from lignocellulosics. In this review, the three important techniques for high yields of fermentable sugars from lignocellulosics and the pretreatment study status, challenges, and future research targets were discussed.

scholarly journals Valorization of waste forest biomass toward the production of cello-oligosaccharides with potential prebiotic activity by utilizing customized enzyme cocktails

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Anthi Karnaouri ◽  
Leonidas Matsakas ◽  
Eleni Krikigianni ◽  
Ulrika Rova ◽  
Paul Christakopoulos
Keyword(s):  
Enzymatic Hydrolysis ◽  
Scale Up ◽  
Forest Biomass ◽  
Value Added ◽  
Point Of View ◽  
Forest Residues ◽  
Cellulose Conversion ◽  
Enzyme Recycling ◽  
Glucose Ratio ◽  
Hydrolysis Of

Abstract Background Production of value-added materials from lignocellulosic biomass residues is an emerging sector that has attracted much attention as it offers numerous benefits from an environmental and economical point of view. Non-digestible oligosaccharides represent a group of carbohydrates that are resistant to gastrointestinal digestion, and therefore, they are considered as potential prebiotic candidates. Such oligosaccharides can derive from the biomass cellulose fraction through a controlled enzymatic hydrolysis that eliminates the yield of monomers. Results In the present study, hydrolysis of organosolv-pretreated forest residues (birch and spruce) was tested in the presence of four cellulases (EG5, CBH7, CBH6, EG7) and one accessory enzyme (LPMO). The optimal enzyme combinations were comprised of 20% EG5, 43% CBH7, 22% TtLPMO, 10% PaCbh6a and 5% EG7 in the case of birch and 35% EG5, 45% CBH7, 10% TtLPMO, 10% PaCbh6a and 5% EG7 in the case of spruce, leading to 22.3% and 19.1 wt% cellulose conversion into cellobiose, respectively. Enzymatic hydrolysis was applied on scale-up reactions, and the produced oligosaccharides (consisted of > 90% cellobiose) were recovered and separated from glucose through nanofiltration at optimized temperature (50 °C) and pressure (10 bar) conditions, yielding a final product with cellobiose-to-glucose ratio of 21.1 (birch) and 20.2 (spruce). Cellobiose-rich hydrolysates were tested as fermentative substrates for different lactic acid bacteria. It was shown that they can efficiently stimulate the growth of two Lactobacilli strains. Conclusions Controlled enzymatic hydrolysis with processive cellulases, combined with product recovery and purification, as well as enzyme recycling can potentially support the sustainable production of food-grade oligosaccharides from forest biomass.

scholarly journals Study of Chemical and Enzymatic Hydrolysis of Cellulosic Material to Obtain Fermentable Sugars

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Myriam A. Amezcua-Allieri ◽  
Teresa Sánchez Durán ◽  
Jorge Aburto
Keyword(s):  
Reaction Time ◽  
Enzymatic Hydrolysis ◽  
Reducing Sugars ◽  
Fermentable Sugars ◽  
Effect Of Temperature ◽  
Acid Pretreatment ◽  
Total Sugars ◽  
Hydroxymethyl Furfural ◽  
Chemical Hydrolysis ◽  
Hydrolysis Of

The objective of this study was to evaluate the chemical and enzymatic hydrolysis using a factorial experimental design (23) in order to obtain fermentable sugars from cellulose-based material (CBM) usually used as pet litter. In assessing chemical hydrolysis, we studied the effect of temperature, in addition to H2SO4 concentration and reaction time, on the production of total sugars, reducing sugars, soluble lignin, carbohydrate profile, furfural (F), and hydroxymethyl furfural (HMF). We performed a response surface analysis and found that, at 100°C, 1% acid concentration, and 60 min reaction time, the yields of 0.0033 g reducing sugar/g biomass and 0.0852 g total sugars/g biomass were obtained. Under the above conditions, F is not generated, while HMF is generated in such a concentration that does not inhibit fermentation. We pretreated the CBM with H2SO4, NaOH, CaO, or ozonolysis, in order to evaluate the effectiveness of the enzymatic hydrolysis from the pretreated biomass, using an enzymatic cocktail. Results showed that CBM with acid was susceptible to enzymatic attack, obtaining a concentration of 0.1570 g reducing sugars/g biomass and 0.3798 g total sugars/g biomass. We concluded that acid pretreatment was the best to obtain fermentable sugars from CBM.

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.

Influence of Enzymatic Cocktails on Conversion of Agricultural Lignocellulose to Fermentable Sugars

2017 ◽  
Vol 68 (2) ◽  
pp. 373-377
Author(s):  
Teodor Vintila ◽  
Vasile Daniel Gherman ◽  
Nicolae Popa ◽  
Dumitru Popescu ◽  
Carmen Buzatu ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Culture Media ◽  
Fermentable Sugars ◽  
Cellulolytic Enzymes ◽  
Crystalline Cellulose ◽  
Agricultural Biomass ◽  
Residual Biomass ◽  
Hydrolysis Process ◽  
High Yields ◽  
Hydrolysis Of

Agricultural lignocellulosic biomass is regarded as an important source of biofuels, especially bioethanol and biohydrogen. The following aspects have been studied: the effect of type of substrate used in production of cellulolytic enzymes, the activity of several enzymatic cocktails used to hydrolyse three types of agricultural biomass and the influence of provenience of enzymatic cocktails on sugars yields in the hydrolysis process. Fungi investigated in this study (T. longibrachiatum DSM 769) release higher titter of enzymes when raw, unpretreated agriculture residual biomass is used as substrate and inducer for biosynthesis of cellulolytic enzymes. Cellulolytic enzymes produced in culture media containing a certain type of agricultural lignocellulosic biomass as substrate, can be used in hydrolysis of other types of agricultural lignocellulosic biomass with similar sugar yields. Cellulases produced in culture media containing purified crystalline cellulose as substrate does not contain all necessary types of enzymes to hydrolyze lignocellulosic complex from agricultural biomass to produce high yields of sugars. On-site production of cellulases can be an effective approach biorefinery of lignocellulose to produce biofuels or other biochemicals by fermentation.

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.

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