Exploring accessibility of pretreated poplar cell walls by measuring dynamics of fluorescent probes

Paës, Gabriel; Habrant, Anouck; Ossemond, Jordane; Chabbert, Brigitte

doi:10.1186/s13068-017-0704-5

Cited by 29 publications

(31 citation statements)

References 62 publications

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“…A more rigorous study on the mechanisms of carbohydratebinding domains (CBMs) was carried out by Paës et al (2015) utilizing FRAP and a set of similar CMBs in a variation of bioinspired assemblies. FRAP has recently been used to investigate diffusion in the wood cell wall for several types of chemical pretreatment methods for large-size dextran molecules (Paës et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Using fluorescent probes and FRAP to investigate macromolecule diffusion in steam-exploded wood

et al. 2018

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Diffusion of fluorescently labeled dextran of varying molecular weight in wood pretreated by steam explosion was studied with a confocal microscope. The steam explosion experiments were conducted at relatively mild conditions relevant for materials biorefinery at a pressure of 14 bars for 10 min. The method of fluorescence recovery after photobleaching (FRAP) was used to perform diffusion measurements locally in the wood microstructure. It was found that the FRAP methodology can be used to observe differences in the diffusion coefficient based on localization in the microstructure, i.e., earlywood, latewood, and cell wall. Microscopic changes due to steam explosion were seen to increase diffusion of the smaller 3-kDa dextran diffusion probe in the earlywood, while the latewood structure was not affected in any significant way. Macroscopic changes to the structure in the form of ruptures due to the steam explosion pretreatment were observed to increase the rate of diffusion for the larger 40-kDa dextran probe.

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Section: Introductionmentioning

confidence: 99%

Using fluorescent probes and FRAP to investigate macromolecule diffusion in steam-exploded wood

et al. 2018

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“…Moreover, the bands of four components in raw PH were significantly weaker than those in pretreated PH, showing that the adsorption of CBH I, CBH II, EG I, and EG II to pretreated PH was stronger than to raw PH. As reported, cellulose was surrounded by hemicellulose and lignin in lignocellulosic materials [ 23 ]. Thus, it was difficult for cellulose of raw PH to contact with cellulase efficiently.…”

Section: Resultsmentioning

confidence: 79%

“…The enzymatic hydrolysis efficiency was determined by structure of the lignocellulosic materials [ 23 ]. The morphology changes of PH before and after being pretreated by H 3 PO 4 /H 2 O 2 could provide direct information for explaining the rapid increase of the hydrolysis efficiency.…”

Section: Resultsmentioning

confidence: 99%

“…Only a few studies focus on producing bio-isoprene using lignocellulose as the carbon source [ 22 ]. The primary reason is that it is very difficult to utilize the lignocellulosic materials directly because the cellulose is surrounded by hemicellulose and lignin [ 23 ] and a huge amount of enzyme would be consumed to hydrolyze cellulose contained in the lignocellulosic materials. Thus, it is vital to remove lignin and hemicellulose from lignocellulosic materials by an appropriate pretreatment method before isoprene production with microorganism fermentation.…”

Section: Introductionmentioning

confidence: 99%

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Production of isoprene, one of the high-density fuel precursors, from peanut hull using the high-efficient lignin-removal pretreatment method

Wang

et al. 2017

Biotechnol Biofuels

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BackgroundIsoprene as the feedstock can be used to produce renewable energy fuels, providing an alternative to replace the rapidly depleting fossil fuels. However, traditional method for isoprene production could not meet the demands for low-energy consumption and environment-friendliness. Moreover, most of the previous studies focused on biofuel production out of lignocellulosic materials such as wood, rice straw, corn cob, while few studies concentrated on biofuel production using peanut hull (PH). As is known, China is the largest peanut producer in the globe with an extremely considerable amount of PH to be produced each year. Therefore, a novel, renewable, and environment-friendly pretreatment strategy to increase the enzymatic hydrolysis efficiency of cellulose and reduce the inhibitors generation was developed to convert PH into isoprene.ResultsThe optimal pretreatment conditions were 100 °C, 60 min, 10% (w/v) solid loading with a 2:8 volume ratio of phosphoric acid and of hydrogen peroxide. In comparison with the raw PH, the hemicellulose and lignin were reduced to 85.0 and 98.0%, respectively. The cellulose–glucose conversion of pretreated PH reached up to 95.0% in contrast to that of the raw PH (19.1%). Only three kinds of inhibitors including formic acid, levulinic acid, and a little furfural were formed during the pretreatment process, whose concentrations were too low to inhibit the isoprene yield for Escherichia coli fermentation. Moreover, compared with the isoprene yield of pure glucose fermentation (298 ± 9 mg/L), 249 ± 6.7 and 294 ± 8.3 mg/L of isoprene were produced using the pretreated PH as the carbon source by the engineered strain via separate hydrolysis and fermentation and simultaneous saccharification and fermentation (SSF) methods, respectively. The isoprene production via SSF had a 9.8% glucose–isoprene conversion which was equivalent to 98.8% of isoprene production via the pure glucose fermentation.ConclusionsThe optimized phosphoric acid/hydrogen peroxide combination pretreatment approach was proved effective to remove lignin and hemicellulose from lignocellulosic materials. Meanwhile, the pretreated PH could be converted into isoprene efficiently in the engineered Escherichia coli. It is concluded that this novel strategy of isoprene production using lignocellulosic materials pretreated by phosphoric acid/hydrogen peroxide is a promising alternative to isoprene production using traditional way which can fully utilize non-renewable fossil sources.

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“…Fluorescence Recovery After Photobleaching (FRAP) technique was recently used to assess the diffusion behaviour of dextrans and labelled cellulases in plant cell wall bioinspired assemblies [ 24 , 25 ]. Mobility of Bacillus subtilis xylanases on wheat flour arabinoxylan and fluorescent probes inside pretreated poplar samples were also investigated directly using the FRAP technique [ 26 , 27 ].…”

Section: Introductionmentioning

confidence: 99%

Dynamical assessment of fluorescent probes mobility in poplar cell walls reveals nanopores govern saccharification

Herbaut

Zoghlami

Paës

2018

Biotechnol Biofuels

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BackgroundImproving lignocellulolytic enzymes’ diffusion and accessibility to their substrate in the plant cell walls is recognised as a critical issue for optimising saccharification. Although many chemical features are considered as detrimental to saccharification, enzymes’ dynamics within the cell walls remains poorly explored and understood. To address this issue, poplar fragments were submitted to hot water and ionic liquid pretreatments selected for their contrasted effects on both the structure and composition of lignocellulose. In addition to chemical composition and porosity analyses, the diffusion of polyethylene glycol probes of different sizes was measured at three different time points during the saccharification.ResultsProbes’ diffusion was mainly affected by probes size and pretreatments but only slightly by saccharification time. This means that, despite the removal of polysaccharides during saccharification, diffusion of probes was not improved since they became hindered by changes in lignin conformation, whose relative amount increased over time. Porosity measurements showed that probes’ diffusion was highly correlated with the amount of pores having a diameter at least five times the size of the probes. Testing the relationship with saccharification demonstrated that accessibility of 1.3–1.7-nm radius probes measured by FRAP on non-hydrolysed samples was highly correlated with poplar digestibility together with the measurement of initial porosity on the range 5–20 nm.ConclusionMobility measurements performed before hydrolysis can serve to explain and even predict saccharification with accuracy. The discrepancy observed between probes’ size and pores’ diameters to explain accessibility is likely due to biomass features such as lignin content and composition that prevent probes’ diffusion through non-specific interactions probably leading to pores’ entanglements.

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Exploring accessibility of pretreated poplar cell walls by measuring dynamics of fluorescent probes

Cited by 29 publications

References 62 publications

Using fluorescent probes and FRAP to investigate macromolecule diffusion in steam-exploded wood

Using fluorescent probes and FRAP to investigate macromolecule diffusion in steam-exploded wood

Production of isoprene, one of the high-density fuel precursors, from peanut hull using the high-efficient lignin-removal pretreatment method

Dynamical assessment of fluorescent probes mobility in poplar cell walls reveals nanopores govern saccharification

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