General Method to Correct the Fluctuation of Acid Based Pretreatment Efficiency of Lignocellulose for Highly Efficient Bioconversion

Han, Xushen; Bao, Jie

doi:10.1021/acssuschemeng.7b04601

Cited by 39 publications

(39 citation statements)

References 31 publications

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“…Bioconversion of lignocellulosic biomass into fuels and chemicals has attracted great interest over last few decades due to the increasing global energy demand, rural development, and environmental safety concerns [ 1 ]. Lignocellulosic biomass is mainly composed of cellulose, hemicellulose and lignin, while it also contains some minor components like ash and extractive in different samples [ 2 , 3 ]. Due to the recalcitrant structure of lignocellulose, commercial development of biomass and bioenergy is limited by the performance of cellulolytic enzyme systems [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Real-time adsorption and action of expansin on cellulose

Duan

Zhao

et al. 2018

Biotechnol Biofuels

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BackgroundBiological pretreatment is an environmentally safe method for disrupting recalcitrant structures of lignocellulose and thereby improving their hydrolysis efficiency. Expansin and expansin-like proteins act synergistically with cellulases during hydrolysis. A systematic analysis of the adsorption behavior and mechanism of action of expansin family proteins can provide a basis for the development of highly efficient pretreatment methods for cellulosic substrates using expansins.ResultsAdsorption of Bacillus subtilis expansin (BsEXLX1) onto cellulose film under different conditions was monitored in real time using a quartz crystal microbalance with dissipation. A model was established to describe the adsorption of BsEXLX1 onto the film. High temperatures increased the initial adsorption rate while reducing the maximum amount of BsEXLX1 adsorbed onto the cellulose. Non-ionic surfactants (polyethylene glycol 4000 and Tween 80) at low concentrations enhanced BsEXLX1 adsorption; whereas, high concentrations had the opposite effect. However, sodium dodecyl sulfate inhibited adsorption at both low and high concentrations. We also investigated the structural changes of cellulose upon BsEXLX1 adsorption and found that BsEXLX1 adsorption decreased the crystallinity index, disrupted hydrogen bonding, and increased the surface area of cellulose, indicating greater accessibility of the substrate to the protein.ConclusionsThese results increase our understanding of the interaction between expansin and cellulose, and provide evidence for expansin treatment as a promising strategy to enhance enzymatic hydrolysis of lignocellulose.Electronic supplementary materialThe online version of this article (10.1186/s13068-018-1318-2) contains supplementary material, which is available to authorized users.

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Section: Introductionmentioning

confidence: 99%

Real-time adsorption and action of expansin on cellulose

Duan

Zhao

et al. 2018

Biotechnol Biofuels

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“…The acid catalyst usage for pretreatment was adjusted according to the method previously described (Han & Bao, 2018). A suspension slurry was prepared by mixing 2 g of raw feedstock (dry base) with 100 ml deionized water in a 250 ml flask, and then shaken vigorously at 30°C for 30 min, and the pH value of the slurry was measured by pH sensor.…”

Section: Methodsmentioning

confidence: 99%

“…The element contents were measured by inductively coupled plasma atomic emission spectrometry (725 ICP‐OES, Agilent) using the simultaneous CCD detector at 1.2 kW, 15 L/min of plasma gas flow, 1.5 L/min of auxiliary gas flow, 0.75 L/min of nebulizer flow, 15 rpm of pump speed, 35 s of sample delay time, and 10 s of stabilization time (Han & Bao, 2018). The samples were prepared by mixing 0.1 g of the ions containing solids or hydrolysate with 3 ml of nitric acid and 1 ml of perchloric acid, then boiled on an electric furnace for 4 h. All the liquid was then transferred into a flask and diluted with deionized water to 25 ml before used for detection.…”

Section: Methodsmentioning

confidence: 99%

Transformation of lignocellulose to starch‐like carbohydrates by organic acid‐catalyzed pretreatment and biological detoxification

Zhang

Khushik

Zhan

et al. 2021

Biotech & Bioengineering

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Corn dry milling provides a mature model for lignocellulose biorefinery process. To copy this technical success, a crucial step is to transform lignocellulose into starch‐like carbohydrates (SLC), similar to milled corn grain and in a similar fashion to corn dry milling. The transformation process should be zero wastewater generation and sufficient fermentable sugar conservation; the product should be in solid particle form, free of toxic residues, and high enzymatic hydrolysis yield and fermentability. Here we designed and verified a SLC transformation process by (i) biodegradable oxalic acid‐catalyzed pretreatment, and (ii) simultaneous biodegradation of inhibitors and oxalic acid catalyst. The oxalic acid catalyst was effective on disrupting the lignocellulose structure and also biodegradable at low pH value. The biodetoxification fungus Paecilomyces variotii FN89 was capable of degrading the furan/phenolic aldehydes and oxalic acid simultaneously and ultimately, while the fermentable sugars were well preserved. The obtained SLC from wheat straw and corn stover were similar to dry milled corn meal in terms of morphological properties, fermentable sugar contents, enzymatic hydrolysis yield, elemental contents, and free of inhibitors and acid catalyst. The bioconversion of starch‐like wheat straw and corn stover produced 78.5 and 75.3 g/L of ethanol (9.9% and 9.5%, v/v) with the yield of 0.47 and 0.45 g ethanol/g cellulose/xylose, respectively, compared with 78.7 g/L (10.0%, v/v) from corn meal and the yield of 0.48 g ethanol/g starch. Mass balances suggest that the ethanol yield, wastewater generation, and elemental recycling of the SLC from lignocellulose were essentially the same as those of corn meal.

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“…Residual xylan in pretreated residues has been described to exert a "blocking effect" upon the substrate's surface, which renders unsuccessful enzymatic digestion [39]. To negate or eliminate the unwanted buffering effects caused by ash during autohydrolysis, strategies of de-washing and addition of sulfuric acid and exchangeable metal salts have been successfully applied in previous work [21,40,41]. Previous studies have also observed that the removal of organic matter alone from the soluble mixtures of EA can lead to an increasing enzymatic digestibility of autohydrolyzed WS with EA components [28].…”

Section: Effects Of Loading Buffering Compounds On the Enzymatic Digementioning

confidence: 99%

Unrevealing model compounds of soil conditioners impacts on the wheat straw autohydrolysis efficiency and enzymatic hydrolysis

Tang

Huang

et al. 2020

Biotechnol Biofuels

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Background: Soil-derived exogenous ash (EA) poses a challenge toward lignocellulosic autohydrolysis due to its buffering capacity. Previous works focusing on this phenomenon have failed to also investigate the role that soluble salts, and organic matter plays in this system. Herein, sodium phosphate and sodium humate were employed as model buffering compounds representing soluble salts and organic matter and dosed into a de-ashed wheat straw (DWS) autohydrolysis process to show the potential impacts of WS attached soil conditioners on the WS autohydrolysis efficiency which would further affect the enzymatic digestibility of autohydrolyzed WS. Results: Results showed that with the increasing loadings of sodium phosphate and sodium humate resulted in elevated pH values (from 4.0 to 5.1 and from 4.1 to 4.7, respectively). Meanwhile, the reductions of xylan removal yields from ~ 84.3-61.4% to 72.3-53.0% by loading (1-30 g/L) sodium phosphate and sodium humate during WS autohydrolysis lead to a significant decrease of cellulose accessibilities which finally lead to a reduction of the enzymatic digestibility of autohydrolyzed WS from ~ 75.4-77.2% to 47.3-57.7%. Conclusion: The existence of different types soil conditioner model compounds results in various component fractions from autohydrolyzed WS in the process of autohydrolysis. A lack of sufficient xylan removal was found to drive the significant decrease in enzymatic accessibility. The results demonstrated the various effects of two typical tested soil conditioners on WS autohydrolysis and enzymatic hydrolysis.

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General Method to Correct the Fluctuation of Acid Based Pretreatment Efficiency of Lignocellulose for Highly Efficient Bioconversion

Cited by 39 publications

References 31 publications

Real-time adsorption and action of expansin on cellulose

Real-time adsorption and action of expansin on cellulose

Transformation of lignocellulose to starch‐like carbohydrates by organic acid‐catalyzed pretreatment and biological detoxification

Unrevealing model compounds of soil conditioners impacts on the wheat straw autohydrolysis efficiency and enzymatic hydrolysis

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