Topochemistry of alkaline, alkaline-peroxide and hydrotropic pretreatments of common reed to enhance enzymatic hydrolysis efficiency

Mou, Hong Yan; Heikkilä, Elli; Fardim, Pedro

doi:10.1016/j.biortech.2013.09.093

Cited by 90 publications

(63 citation statements)

References 25 publications

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“…34 On the other hand, the surface distribution of lignin and xylan is also of critical importance for enzymatic hydrolysis. 17 According to the results in Figure 3, the highest glucan yield could be achieved Table 2) on bagasse fibers after hydrotropic pretreatment. Similar results were also reported for the pretreatment of common reed.…”

Section: ■ Results and Discussionmentioning

confidence: 88%

Topochemistry of Environmentally Friendly Pretreatments To Enhance Enzymatic Hydrolysis of Sugar Cane Bagasse to Fermentable Sugar

Mou

Heikkilä

Fardim

2014

J. Agric. Food Chem.

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In this work, dilute alkaline and alkaline peroxide pretreatments were conducted in comparison with hydrotropic pretreatment to improve the delignification of bagasse prior to enzymatic hydrolysis. The surface chemical composition of bagasse after pretreatments was investigated by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The surface distribution of lignin and extractives on the bagasse fiber was significantly changed by dilute alkaline, alkaline peroxide, and hydrotropic pretreatments. Hydrotropic pretreatment typically showed, other than the decrease of surface coverage by lignin and extractives, dramatic removal of xylan, thereby leading to more cellulose exposed on the fiber surface after pretreatment. Fiber morphology after pretreatments was more favorable for enzyme hydrolysis as well. However, the hydrotropic treatment had clear advantages because the enzymatic hydrolysis yields of glucan and xylan of pretreated bagasse were 83.9 and 14.3%, respectively.

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Section: ■ Results and Discussionmentioning

confidence: 88%

Topochemistry of Environmentally Friendly Pretreatments To Enhance Enzymatic Hydrolysis of Sugar Cane Bagasse to Fermentable Sugar

Mou

Heikkilä

Fardim

2014

J. Agric. Food Chem.

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“…Lignin extractions using organosolv, soda/AQ and hydrotropic treatments were performed according to conditions used in previous works (Table 2) [13, 21, 24, 26]. In brief, 100 g (dry weight) of steam-pretreated poplar biomass was heated at 170 °C for 1 h at a liquid–solid ratio of 7:1 using a four-vessel (2 L each) rotating digester (Aurora Products, Savona, BC, Canada).…”

Section: Methodsmentioning

confidence: 99%

“…The third delignification method that was evaluated used hydrotropic salts which are water-soluble organic amphiphilic compounds that form molecular aggregates when the salt concentration is sufficiently high. Hydrotropic salts have been shown to dissolve large amounts of lignin [23, 24]. However, it should be noted that each of these delignification methods limits the effective recovery of the hemicellulose component from the spent liquors [11, 25] and can result in some hemicellulose degradation [7].…”

Section: Introductionmentioning

confidence: 99%

A comparison of various lignin-extraction methods to enhance the accessibility and ease of enzymatic hydrolysis of the cellulosic component of steam-pretreated poplar

Tian

Chandra

Lee

et al. 2017

Biotechnol Biofuels

139

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BackgroundCurrent single-stage delignification-pretreatment technologies to overcome lignocellulosic biomass recalcitrance are usually achieved at the expense of compromising the recovery of the polysaccharide components, particularly the hemicellulose fraction. One way to enhance overall sugar recovery is to tailor an efficient two-stage pretreatment that can pre-extract the more labile hemicellulose component before subjecting the cellulose-rich residual material to a second-stage delignification process. Previous work had shown that a mild steam pretreatment could recover >65% of the hemicellulose from poplar while limiting the acid-catalysed condensation of lignin. This potentially allowed for subsequent lignin extraction using various lignin solvents to produce a more accessible cellulosic substrate.ResultsA two-stage approach using steam and/or solvent pretreatment was assessed for its ability to separate hemicellulose and lignin from poplar wood chips while providing a cellulose-rich fraction that could be readily hydrolysed by cellulase enzymes. An initial steam-pretreatment stage was performed over a range of temperatures (160–200 °C) using an equivalent severity factor of 3.6. A higher steam temperature of 190 °C applied over a shorter residence time of 10 min effectively solubilized and recovered 75% of the hemicellulose while enhancing the ability of various solvents [deep eutectic solvent (DES), ethanol organosolv, soda/anthraquinone (soda/AQ) or a hydrotrope] to extract lignin in a second stage. When the second-stage treatments were compared, the mild DES treatment (lactic acid and betaine) at 130 °C, removed comparable amounts of lignin with higher selectivity than did the soda/AQ and organosolv pretreatments at 170 °C. However, the cellulose-rich substrates obtained after the second-stage organosolv and soda/AQ pretreatments showed the highest cellulose accessibility, as measured by the Simon’s staining technique. They were also the most susceptible to subsequent enzymatic hydrolysis.ConclusionsThe second-stage pretreatments varied in their ability to solubilize and extract the lignin component of steam-pretreated poplar while enhancing the enzymatic hydrolysis of the resulting cellulose-rich residual fractions. Although DES extraction was more selective in extracting lignin from the steam-pretreated substrates, the organosolv and soda/AQ post treatments disrupted the cellulose structure to a greater extent while enhancing the ease of enzymatic hydrolysis. Graphical abstractEffective hemicellulose removal via steam pretreatment followed by subsequent lignin extraction under acidic, alkaline or solvolytic conditions results in a highly accessible, more readily hydrolysed cellulose fraction.

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“…ToF‐SIMS analysis revealed that the most efficient enzymatic hydrolysis occurred with the hydrotropic pretreated sample; the enzymatically hydrolyzed hydrotropic sample was lower 58.1% and 64.3% for the carbohydrates/lignin ratio and the guaiacyl/total lignin ratio, respectively, compared to the pretreated sample . Through ToF‐SIMS images, it was determined that residual lignin location on the surface fiber changed after the pretreatments and that decrease in lignin allowed for more carbohydrates to be exposed . Now, the carbohydrate ToF‐SIMS data should be used carefully as the authors used m/z 115 and 133 peaks in addition to m/z 127 and 145 , and Goacher et al.…”

Section: Chemical Biological and Genetic Modification In Biomassmentioning

confidence: 99%

Advances in understanding the surface chemistry of lignocellulosic biomass via time‐of‐flight secondary ion mass spectrometry

Tolbert

Ragauskas

2016

Energy Science & Engineering

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Overcoming the natural recalcitrance of lignocellulosic biomass is necessary in order to efficiently convert biomass into biofuels or biomaterials and many times this requires some type of chemical pretreatment and/or biological treatment. While bulk chemical analysis is the traditional method of determining the impact a treatment has on biomass, the chemistry on the surface of the sample can differ from the bulk chemistry. Specifically, enzymes and microorganisms bind to the surface of the biomass and their efficiency could be greatly impacted by the chemistry of the surface. Therefore, it is important to study and understand the chemistry of the biomass at the surface. Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) is a powerful tool that can spectrally and spatially analyze the surface chemistry of a sample. This review discusses the advances in understanding lignocellulosic biomass surface chemistry using the ToF‐SIMS by addressing the instrument parameters, biomass sample preparation, and characteristic lignocellulosic ion fragmentation peaks along with their typical location in the plant cell wall. The use of the ToF‐SIMS in detecting chemical changes due to chemical pretreatments, microbial treatments, and physical or genetic modifications is discussed along with possible future applications of the instrument in lignocellulosic biomass studies.

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Topochemistry of alkaline, alkaline-peroxide and hydrotropic pretreatments of common reed to enhance enzymatic hydrolysis efficiency

Cited by 90 publications

References 25 publications

Topochemistry of Environmentally Friendly Pretreatments To Enhance Enzymatic Hydrolysis of Sugar Cane Bagasse to Fermentable Sugar

Topochemistry of Environmentally Friendly Pretreatments To Enhance Enzymatic Hydrolysis of Sugar Cane Bagasse to Fermentable Sugar

A comparison of various lignin-extraction methods to enhance the accessibility and ease of enzymatic hydrolysis of the cellulosic component of steam-pretreated poplar

Advances in understanding the surface chemistry of lignocellulosic biomass via time‐of‐flight secondary ion mass spectrometry

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