Comparison of the susceptibility of two hardwood species, Mimosa scabrella Benth and Eucalyptus viminalis labill, to steam explosion and enzymatic hydrolysis

Steam explosion of two hardwood species was carried out with and without addition of sulfuric acid (H2SO4 0.5%, p/v) as a pretreatment catalyst. In general, wood chips of Eucalyptus viminalis Labill were shown to be more amenable to pretreatment than chips derived from bolds of Mimosa scabrella Benth (bracatinga). This was apparent from all pretreatment parameters tested including the overall recovery yields of pretreated fractions, carbohydrates (pentoses and hexoses) recovered as water-solubles, yield of dehydration by-products and lignin susceptibility to acid hydrolysis. There was no evidence for complete deacetylation of both wood species during pretreatment and lignin appeared to undergo extensive acid hydrolysis at higher pretreatment severities. Steam treatment at 205ºC for 5 min without addition of an acid catalyst was shown to be uncapable of removing the hemicellulose component from bracatinga chips, as determined by chemical analysis of the steam-treated water-insoluble fractions. Nearly 30% of the hemicellulose (xylan) found in bracatinga remained unhydrolysed after pretreatment, whereas more than 90% of this component could be removed from eucalypt chips under the same pretreatment conditions. Likewise, pretreatment of eucalypt chips resulted in a more extensive solubilization of glucans (cellulose) by acid hydrolysis. Addition of dilute H2SO4 as a pretreatment catalyst generally increased the recovery yield of fermentable sugars in the water-soluble fractions and this effect was more pronounced for the pretreatment of bracatinga chips. Steam-treated substrates produced from bracatinga were also less accessible to enzymatic hydrolysis than those produced from eucalypt chips, regardless of the use of an acid catalyst.

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Acid and Enzymatic Hydrolyses of Rice Bran for Bioethanol Production

ALCHEMY ◽

10.18860/al.v6i1.6767 ◽

2018 ◽

Vol 6 (1) ◽

pp. 24

Author(s):

Dewi Yuliani ◽

Khoirul Achmad Julianto ◽

Akyunul Jannah

Keyword(s):

Enzymatic Hydrolysis ◽

Hydrochloric Acid ◽

Acid Hydrolysis ◽

Sulphuric Acid ◽

Rice Bran ◽

Dilute Hydrochloric Acid ◽

Cellulolytic Enzyme ◽

Bioethanol Production ◽

By Products ◽

Sugar Source

Rice bran is one among many agricultural by-products containing ~50-60 wt.% of carbohydrate. The carbohydrate is a prominent sugar source for bioethanol production. The objective of this research was to study bioethanol production from rice bran by acid and enzymatic treatment. The variations of acid used were dilute hydrochloric acid and sulphuric acid, while variations of enzyme used were amylolytic and cellulolytic enzyme. Ethanol production of acid-hydrolyzed rice bran was 24.95±1.61% (v/v) by hydrochloric acid and 29.57±2.04% (v/v) by sulphuric acid. Ethanol produced by enzymatic hydrolysis was quite low i.e. 6.7±0.04%, and 8.86±0.29% (v/v) for amylolytic and cellulolytic hydrolysate, respectively. Keywords: Bioethanol, rice bran, acid hydrolysis, enzymatic hydrolysis

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The production of D-xylose by enzymatic hydrolysis of agricultural wastes

Water Science & Technology ◽

10.2166/wst.2002.0414 ◽

2002 ◽

Vol 45 (12) ◽

pp. 97-102 ◽

Cited By ~ 3

Author(s):

C.H. Cho ◽

M. Hatsu ◽

K. Takamizawa

Keyword(s):

Enzymatic Hydrolysis ◽

Acid Hydrolysis ◽

Sunflower Seed ◽

Steam Explosion ◽

Agricultural Wastes ◽

Rhizomucor Pusillus ◽

Enzyme Solution ◽

Penicillium Sp ◽

Hydrolysis Of ◽

Mixed Crude

Agricultural wastes, rich in D-xylose content, were hydrolyzed using the mixed crude enzymes produced by Penicillium sp. AHT-1 and Rhizomucor pusillus HHT-1. Shells of pistachio, peanut, walnut, chestnut, barley brans and sunflower seed peels, were used as raw or pretreated forms. Pretreatment was performed by milling or steam explosion. Enzymatic hydrolysis after steam explosion was more effective than milling processing. More than 13 g of D-xylose was produced from 100 g of milled pistachio shells, walnut shells, sunflower seed peels and peanut shells (less than 0.5 mm size) by the action of mixed enzyme solutions. A maximum of 36 g of D-xylose was produced from 100 g of milled pistachio shells when mixed enzyme solution, containing 3,000 U and 33 U per g of substrate with xylanase and β-xyosidase activities, respectively, was applied. The ratio of the enzymatic hydrolysis as compared to acid hydrolysis in this finding was 100%.

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Steam Explosion Pretreatment of Beechwood. Part 1: Comparison of the Enzymatic Hydrolysis of Washed Solids and Whole Pretreatment Slurry at Different Solid Loadings

Energies ◽

10.3390/en13143653 ◽

2020 ◽

Vol 13 (14) ◽

pp. 3653 ◽

Cited By ~ 1

Author(s):

Robert Balan ◽

Andrzej Antczak ◽

Simone Brethauer ◽

Tomasz Zielenkiewicz ◽

Michael H. Studer

Keyword(s):

Enzymatic Hydrolysis ◽

Lignocellulosic Biomass ◽

Steam Explosion ◽

Optimization Procedure ◽

Reaction Conditions ◽

Steam Explosion Pretreatment ◽

Pretreatment Temperature ◽

Pretreatment Conditions ◽

Whole Slurry ◽

Hydrolysis Of

Steam explosion is a well-known process to pretreat lignocellulosic biomass in order to enhance sugar yields in enzymatic hydrolysis, but pretreatment conditions have to be optimized individually for each material. In this study, we investigated how the results of a pretreatment optimization procedure are influenced by the chosen reaction conditions in the enzymatic hydrolysis. Beechwood was pretreated by steam explosion and the resulting biomass was subjected to enzymatic hydrolysis at glucan loadings of 1% and 5% employing either washed solids or the whole pretreatment slurry. For enzymatic hydrolysis in both reaction modes at a glucan loading of 1%, the glucose yields markedly increased with increasing severity and with increasing pretreatment temperature at identical severities and maximal values were reached at a pretreatment temperature of 230 °C. However, the optimal severity was 5.0 for washed solids enzymatic hydrolysis, but only 4.75 for whole slurry enzymatic hydrolysis. When the glucan loading was increased to 5%, glucose yields hardly increased for pretreatment temperatures between 210 and 230 °C at a given severity, and a pretreatment temperature of 220 °C was sufficient under these conditions. Consequently, it is important to precisely choose the desired conditions of the enzymatic hydrolysis reaction, when aiming to optimize the pretreatment conditions for a certain biomass.

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Is Steam Explosion a Promising Pretreatment for Acid Hydrolysis of Lignocellulosic Biomass?

Processes ◽

10.3390/pr8121626 ◽

2020 ◽

Vol 8 (12) ◽

pp. 1626

Author(s):

David Steinbach ◽

Andrea Kruse ◽

Jörg Sauer ◽

Jonas Storz

Keyword(s):

Acid Hydrolysis ◽

Lignocellulosic Biomass ◽

Steam Explosion ◽

Complex Structure ◽

Beech Wood ◽

Soluble Sugars ◽

Water Soluble ◽

Special Importance ◽

Hydrolysis Of ◽

Subsequent Acid

For the production of sugars and biobased platform chemicals from lignocellulosic biomass, the hydrolysis of cellulose and hemicelluloses to water-soluble sugars is a crucial step. As the complex structure of lignocellulosic biomass hinders an efficient hydrolysis via acid hydrolysis, a suitable pretreatment strategy is of special importance. The pretreatment steam explosion was intended to increase the accessibility of the cellulose fibers so that the subsequent acid hydrolysis of the cellulose to glucose would take place in a shorter time. Steam explosion pretreatment was performed with beech wood chips at varying severities with different reaction times (25–34 min) and maximum temperatures (186–223 °C). However, the subsequent acid hydrolysis step of steam-exploded residue was performed at constant settings at 180 °C with diluted sulfuric acid. The concentration profiles of the main water-soluble hydrolysis products were recorded. We showed in this study that the defibration of the macrofibrils in the lignocellulose structure during steam explosion does not lead to an increased rate of cellulose hydrolysis. So, steam explosion is not a suitable pretreatment for acid hydrolysis of hardwood lignocellulosic biomass.

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Steam Explosion Pretreatment of Beechwood. Part 2: Quantification of Cellulase Inhibitors and Their Effect on Avicel Hydrolysis

Energies ◽

10.3390/en13143638 ◽

2020 ◽

Vol 13 (14) ◽

pp. 3638

Author(s):

Simone Brethauer ◽

Andrzej Antczak ◽

Robert Balan ◽

Tomasz Zielenkiewicz ◽

Michael H. Studer

Keyword(s):

Acetic Acid ◽

Enzymatic Hydrolysis ◽

Steam Explosion ◽

Biomass Pretreatment ◽

Reaction Conditions ◽

Steam Explosion Pretreatment ◽

Wide Range ◽

Pretreatment Conditions ◽

Whole Slurry ◽

Hydrolysis Of

Biomass pretreatment is a mandatory step for the biochemical conversion of lignocellulose to chemicals. During pretreatment, soluble compounds are released into the prehydrolyzate that inhibit the enzymatic hydrolysis step. In this work, we investigated how the reaction conditions in steam explosion pretreatment of beechwood (severity: 3.0–5.25; temperature: 160–230 °C) influence the resulting amounts of different inhibitors. Furthermore, we quantified the extent of enzyme inhibition during enzymatic hydrolysis of Avicel in the presence of the prehydrolyzates. The amounts of phenolics, HMF, acetic acid and formic acid increased with increasing pretreatment severities and maximal quantities of 21.6, 8.3, 43.7 and 10.9 mg/gbeechwood, respectively, were measured at the highest severity. In contrast, the furfural concentration peaked at a temperature of 200 °C and a severity of 4.75. The presence of the prehydrolyzates in enzymatic hydrolysis of Avicel lowered the glucose yields by 5–26%. Mainly, the amount of phenolics and xylose and xylooligomers contributed to the reduced yield. As the maximal amounts of these two inhibitors can be found at different conditions, a wide range of pretreatment severities led to severely inhibiting prehydrolyzates. This study may provide guidelines when choosing optimal pretreatment conditions for whole slurry enzymatic hydrolysis.

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Sugars Production from Municipal Forestry and Greening Wastes Pretreated by an Integrated Steam Explosion-Based Process

Energies ◽

10.3390/en13174432 ◽

2020 ◽

Vol 13 (17) ◽

pp. 4432 ◽

Cited By ~ 2

Author(s):

Maria José Negro ◽

Cristina Álvarez ◽

Pablo Doménech ◽

Raquel Iglesias ◽

Ignacio Ballesteros

Keyword(s):

Enzymatic Hydrolysis ◽

Steam Explosion ◽

Dilute Acid ◽

Waste Streams ◽

Enzyme Loading ◽

Glucose Yield ◽

Resource Sustainability ◽

Solids Loading ◽

Biological Conversion ◽

Pretreatment Conditions

Increasing awareness of resource sustainability and waste management has led to the search for solutions while promoting circular economy principles. Among all kinds of lignocellulosic biomass available, one with growing interest is municipal forestry and greening waste (MFGW). MFGW makes up an important part of waste streams of municipal solid waste and is a potential feedstock for biological conversion in a lignocellulosic biorefinery. This work studied the fermentable sugars production from MFGW after steam explosion (SE) pretreatment combined with other pretreatments such as dilute acid, organosolv, and metal salts. A range of pretreatment conditions was evaluated according to different parameters: sugars recovery, degradation product generation, and enzymatic hydrolysis yield. At selected pretreatment conditions (diluted acid plus SE, 195 °C, 10 min, and 60 mg H2SO4/g MFGW), 77% of potential sugars content in MFGW was obtained. The effect of solids loading and enzyme dose on glucose release and glucose yield on enzymatic hydrolysis were also determined. Up to 70% of the main sugars in the MFGW were recovered for the coupled pretreatment and enzymatic hydrolysis (45 FPU/g glucan enzyme loading and 20% dry matter solid consistency), resulting in 80 g/L glucose that could be further utilized for ethanol production.

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Steam explosion of wood particles from fibreboard and particle board with indirect control by enzymatic hydrolysis

Acta Chimica Slovaca ◽

10.2478/acs-2019-0026 ◽

2019 ◽

Vol 12 (2) ◽

pp. 185-191

Author(s):

Andrej Pažitný

Keyword(s):

Enzymatic Hydrolysis ◽

Steam Explosion ◽

Lignocellulosic Materials ◽

Particle Board ◽

Severity Factor ◽

Cellulose Accessibility ◽

Indirect Control ◽

Commercial Enzymes ◽

Wood Particles ◽

Pretreatment Conditions

Abstract Pretreatment of particles obtained from lignocellulosic materials by steam explosion with indirect control by enzymatic hydrolysis has been studied. The dendromass pretreatment model has been applied for recycled fibreboard and particle board based on softwood. Their structure and chemical composition partly predetermine these lignocellulosic materials consisting of a mixture of spruce and fir particles also for bioethanol production. Optimum steam explosion temperature of 205 °C was determined based on the concentration of total monosaccharides — glucose, xylose and arabinose, among all experimentally prepared hydrolysates. This corresponds to basic conditions for fine disintegration of biomass to lignocellulosic structure with good holocellulose accessibility. Particles obtained from fibreboard and particle board primarily consisting of softwood without steam explosion pretreatment provide relatively low cellulose accessibility for commercial enzymes activity while monosaccharides concentration is partly reduced because of torrefaction at high temperatures. The concentration of monosaccharides in hydrolysates was determined for original sample and each steam explosion temperature. Based on the steam explosion conditions, the effect of severity factors was investigated to find optimum pretreatment conditions to increase accessibility of softwood cellulose and hemicelluloses. The identified optimum severity factor RO = 4.09 matches the optimum steam explosion temperature of 205 °C and the residence time of 10 minutes.

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Steam Explosion for Wheat Straw Pretreatment for Sugars Production

Bioethanol ◽

10.1515/bioeth-2016-0003 ◽

2016 ◽

Vol 2 (1) ◽

Cited By ~ 32

Author(s):

Pablo Alvira ◽

María José Negro ◽

Ignacio Ballesteros ◽

Alberto González ◽

Mercedes Ballesteros

Keyword(s):

Enzymatic Hydrolysis ◽

Wheat Straw ◽

Steam Explosion ◽

Large Scale ◽

Degradation Products ◽

Transport Sector ◽

High Solids Loading ◽

Hydrolysis Process ◽

Pretreatment Conditions ◽

Pretreated Wheat Straw

AbstractDevelopment of biofuels such as lignocellulosic ethanol represents a sustainable alternative in the transport sector. Wheat straw is a promising feedstock for bioethanol production in Europe due to its large production and high carbohydrates content. In a process to produce cellulosic ethanol, previous to the enzymatic hydrolysis to obtain fermentable sugars and the subsequent fermentation, a pretreatment step to break down the recalcitrance of lignocellulose fiber is essential. In this work, a range of steam explosion pretreatment conditions were evaluated according to different parameters: sugars recovery, degradation products generation, and enzymatic hydrolysis yields. Moreover, the enzymatic hydrolysis process was also studied at high substrate loadings, since operating at high solids loading is crucial for large scale development of ethanol production. Pretreatment at 200°C - 10 min resulted in higher enzymatic hydrolysis yield (91.7%) and overall glucose yields (35.4 g glucose/100 g wheat straw) but also higher production of toxic compound. In turn, the characteristics of the pretreated wheat straw at lower severity (Log R0=3.65) correspond to 190°C and 10 min, with minimal sugars degradation and toxics formation indicated a great potential for maximizing total sugars production by using optimal enzyme combinations including accessory enzymes in the enzymatic hydrolysis step.

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Analytical Characterization of Water-Soluble Constituents in Olive-Derived By-Products

Foods ◽

10.3390/foods10061299 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1299

Author(s):

Pablo Doménech ◽

Aleta Duque ◽

Isabel Higueras ◽

José Luis Fernández ◽

Paloma Manzanares

Keyword(s):

Olive Tree ◽

Mediterranean Area ◽

Water Soluble ◽

Olive Pomace ◽

Olive Leaves ◽

Olive Stone ◽

Olive Trees ◽

Tree Pruning ◽

By Products

Olive trees constitute one of the largest agroindustries in the Mediterranean area, and their cultivation generates a diverse pool of biomass by-products such as olive tree pruning (OTP), olive leaves (OL), olive stone (OS), and extracted olive pomace (EOP). These lignocellulosic materials have varying compositions and potential utilization strategies within a biorefinery context. The aim of this work was to carry out an integral analysis of the aqueous extractives fraction of these biomasses. Several analytical methods were applied in order to fully characterize this fraction to varying extents: a mass closure of >80% was reached for EOP, >76% for OTP, >65% for OS, and >52% for OL. Among the compounds detected, xylooligosaccharides, mannitol, 3,4-dihydroxyphenylglycol, and hydroxytyrosol were noted as potential enhancers of the valorization of said by-products. The extraction of these compounds is expected to be more favorable for OTP, OL, and EOP, given their high extractives content, and is compatible with other utilization strategies such as the bioconversion of the lignocellulosic fraction into biofuels and bioproducts.

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Highly-Efficient Release of Ferulic Acid from Agro-Industrial By-Products via Enzymatic Hydrolysis with Cellulose-Degrading Enzymes: Part I–The Superiority of Hydrolytic Enzymes Versus Conventional Hydrolysis

Foods ◽

10.3390/foods10040782 ◽

2021 ◽

Vol 10 (4) ◽

pp. 782

Author(s):

Karina Juhnevica-Radenkova ◽

Jorens Kviesis ◽

Diego A. Moreno ◽

Dalija Seglina ◽

Fernando Vallejo ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Ferulic Acid ◽

Hydrolytic Enzymes ◽

Structural Complexity ◽

Triticum Aestivum L ◽

Feed Supplement ◽

Degrading Enzymes ◽

Secale Cereale L ◽

Pre Treatment ◽

By Products

Historically Triticum aestívum L. and Secale cereále L. are widely used in the production of bakery products. From the total volume of grain cultivated, roughly 85% is used for the manufacturing of flour, while the remaining part is discarded or utilized rather inefficiently. The limited value attached to bran is associated with their structural complexity, i.e., the presence of cellulose, hemicellulose, and lignin, which makes this material suitable mostly as a feed supplement, while in food production its use presents a challenge. To valorize these materials to food and pharmaceutical applications, additional pre-treatment is required. In the present study, an effective, sustainable, and eco-friendly approach to ferulic acid (FA) production was demonstrated through the biorefining process accomplished by non-starch polysaccharides degrading enzymes. Up to 11.3 and 8.6 g kg−1 of FA was released from rye and wheat bran upon 24 h enzymatic hydrolysis with multi-enzyme complex Viscozyme® L, respectively.

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