scholarly journals Physical–chemical properties of cell wall interface significantly correlated to the complex recalcitrance of corn straw

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yufen Wang ◽  
Xianyang Xu ◽  
Huiting Xue ◽  
Dejian Zhang ◽  
Guanhua Li

Abstract Background Tissue heterogeneity significantly influences the overall saccharification efficiency of plant biomass. However, the mechanisms of specific organ or tissue recalcitrance to enzymatic deconstruction are generally complicated and unclear. A multidimensional analysis of the anatomical fraction from 12 corn cultivars was conducted to understand the essence of recalcitrance. Results The results showed that leaf, leaf sheath, stem pith and stem rind of corn straw exhibited remarkable heterogeneity in chemical composition, physical structure and cell type, which resulted in the different saccharification ratio of cellulose. The high saccharification ratio ranging from 21.47 to 38.96% was in stem pith, whereas the low saccharification ratio ranging from 17.1 to 27.43% was in leaf sheath. High values of lignin, hemicelluloses, degree of polymerization and crystallinity index were critical for the increased recalcitrance, while high value of neutral detergent soluble and pore size generated weak recalcitrance. Interestingly, pore traits of cell wall, especial for microcosmic interface structure, seemed to be a crucial factor that correlated to cellulase adsorption and further affected saccharification. Conclusions Highly heterogeneity in cell wall traits influenced the overall saccharification efficiency of biomass. Furthermore, the holistic outlook of cell wall interface was indispensable to understand the recalcitrance and promote the biomass conversion. Graphic abstract

2021 ◽  
Author(s):  
Yufen Wang ◽  
Xianyang Xu ◽  
Huiting Xue ◽  
Dejian Zhang ◽  
Guanhua Li

Abstract Background: Tissue heterogeneity significantly influences the overall saccharification efficiency of plant biomass. However, the mechanisms of specific organ or tissue recalcitrance to enzymatic deconstruction are generally complicated and unclear. A multidimensional analysis for the four parts from twelve corn cultivars was conducted.Results: The results showed that leaf, sheath, pith and rind of corn straw exhibited remarkable heterogeneity in chemical composition, physical structure and cell type, which resulted in the different recalcitrance to enzymatic hydrolysis. High values of lignin, hemicelluloses, degree of polymerization and crystallinity index were critical for the increased recalcitrance, while high value of neutral detergent soluble and pore size generated weak recalcitrance. Interestingly, pore traits of cell wall, especial for microcosmic interface structure, seemed to be a crucial factor that correlated to cellulase adsorption and further affected saccharification.Conclusions: Tissue heterogeneity in physical-chemical traits of cell wall influences the overall saccharification efficiency of biomass. Furthermore, the holistic outlook of cell wall interface is indispensable to understand the recalcitrance and promote the biomass conversion.


2020 ◽  
Vol 7 (9) ◽  
pp. 200967
Author(s):  
Chengqi Feng ◽  
Juan Du ◽  
Shuai Wei ◽  
Chengrong Qin ◽  
Chen Liang ◽  
...  

The efficient separation of bagasse components was achieved by p -toluenesulfonic acid ( p -TsOH) pretreatment. The effects of p -TsOH dosage, reaction temperature and reaction time on cellulose, hemicellulose and lignin contents were studied. Eighty-five per cent of lignin was dissolved, whereas the cellulose loss was minimal (less than 8.1%). Cellulose-rich water-insoluble residual solids were obtained. The degree of polymerization of cellulose decreased slightly, but the crystallinity index (CrI) increased from 52.0% to 68.1%. It indicated that the highly efficient delignification of bagasse was achieved by p -TsOH pretreatment. The nanocellulose filaments (CNFs) were produced by the treated samples. The physico-chemical properties of CNFs were characterized by transmission electron microscopy and thermogravimetric analysis. The results show that the CNFs have smaller average size and higher thermal stability. It provides a new method for CNFs.


2019 ◽  
Vol 3 (1) ◽  
pp. 195-207 ◽  
Author(s):  
Jin Zhang ◽  
Mi Li ◽  
Anthony C. Bryan ◽  
Chang Geun Yoo ◽  
William Rottmann ◽  
...  

Cell wall recalcitrance is the major obstacle for plant biomass conversion to biofuels.


2018 ◽  
Vol 28 (4) ◽  
pp. 169-178 ◽  
Author(s):  
Hyun-Ju Hwang ◽  
Yong Tae Kim ◽  
Nam Seon Kang ◽  
Jong Won Han

The algal cell wall is a potent barrier for delivery of transgenes for genetic engineering. Conventional methods developed for higher plant systems are often unable to penetrate or remove algal cell walls owing to their unique physical and chemical properties. Therefore, we developed a simple transformation method for <i>Chlamydomonas reinhardtii</i> using commercially available enzymes. Out of 7 enzymes screened for cell wall disruption, a commercial form of subtilisin (Alcalase) was the most effective at a low concentration (0.3 Anson units/mL). The efficiency was comparable to that of gamete lytic enzyme, a protease commonly used for the genetic transformation of <i>C. reinhardtii</i>. The transformation efficiency of our noninvasive method was similar to that of previous methods using autolysin as a cell wall-degrading enzyme in conjunction with glass bead transformation. Subtilisin showed approximately 35% sequence identity with sporangin, a hatching enzyme of <i>C. reinhardtii</i>, and shared conserved active domains, which may explain the effective cell wall degradation. Our trans­formation method using commercial subtilisin is more reliable and time saving than the conventional method using autolysin released from gametes for cell wall lysis.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
K. Hodgson-Kratky ◽  
G. Papa ◽  
A. Rodriguez ◽  
V. Stavila ◽  
B. Simmons ◽  
...  

Abstract Background Lignocellulosic biomass is recognized as a promising renewable feedstock for the production of biofuels. However, current methods for converting biomass into fermentable sugars are considered too expensive and inefficient due to the recalcitrance of the secondary cell wall. Biomass composition can be modified to create varieties that are efficiently broken down to release cell wall sugars. This study focused on identifying the key biomass components influencing plant cell wall recalcitrance that can be targeted for selection in sugarcane, an important and abundant source of biomass. Results Biomass composition and the amount of glucan converted into glucose after saccharification were measured in leaf and culm tissues from seven sugarcane genotypes varying in fiber composition after no pretreatment and dilute acid, hydrothermal and ionic liquid pretreatments. In extractives-free sugarcane leaf and culm tissue, glucan, xylan, acid-insoluble lignin (AIL) and acid-soluble lignin (ASL) ranged from 20 to 32%, 15% to 21%, 14% to 20% and 2% to 4%, respectively. The ratio of syringyl (S) to guaiacyl (G) content in the lignin ranged from 1.5 to 2.2 in the culm and from 0.65 to 1.1 in the leaf. Hydrothermal and dilute acid pretreatments predominantly reduced xylan content, while the ionic liquid (IL) pretreatment targeted AIL reduction. The amount of glucan converted into glucose after 26 h of pre-saccharification was highest after IL pretreatment (42% in culm and 63.5% in leaf) compared to the other pretreatments. Additionally, glucan conversion in leaf tissues was approximately 1.5-fold of that in culm tissues. Percent glucan conversion varied between genotypes but there was no genotype that was superior to all others across the pretreatment groups. Path analysis revealed that S/G ratio, AIL and xylan had the strongest negative associations with percent glucan conversion, while ASL and glucan content had strong positive influences. Conclusion To improve saccharification efficiency of lignocellulosic biomass, breeders should focus on reducing S/G ratio, xylan and AIL content and increasing ASL and glucan content. This will be key for the development of sugarcane varieties for bioenergy uses.


2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Isaac Cann ◽  
Gabriel V. Pereira ◽  
Ahmed M. Abdel-Hamid ◽  
Heejin Kim ◽  
Daniel Wefers ◽  
...  

ABSTRACT Renewable fuels have gained importance as the world moves toward diversifying its energy portfolio. A critical step in the biomass-to-bioenergy initiative is deconstruction of plant cell wall polysaccharides to their unit sugars for subsequent fermentation to fuels. To acquire carbon and energy for their metabolic processes, diverse microorganisms have evolved genes encoding enzymes that depolymerize polysaccharides to their carbon/energy-rich building blocks. The microbial enzymes mostly target the energy present in cellulose, hemicellulose, and pectin, three major forms of energy storage in plants. In the effort to develop bioenergy as an alternative to fossil fuel, a common strategy is to harness microbial enzymes to hydrolyze cellulose to glucose for fermentation to fuels. However, the conversion of plant biomass to renewable fuels will require both cellulose and hemicellulose, the two largest components of the plant cell wall, as feedstock to improve economic feasibility. Here, we explore the enzymes and strategies evolved by two well-studied bacteria to depolymerize the hemicelluloses xylan/arabinoxylan and mannan. The sets of enzymes, in addition to their applications in biofuels and value-added chemical production, have utility in animal feed enzymes, a rapidly developing industry with potential to minimize adverse impacts of animal agriculture on the environment.


2020 ◽  
Vol 117 (11) ◽  
pp. 6003-6013 ◽  
Author(s):  
Vincent W. Wu ◽  
Nils Thieme ◽  
Lori B. Huberman ◽  
Axel Dietschmann ◽  
David J. Kowbel ◽  
...  

Filamentous fungi, such asNeurospora crassa, are very efficient in deconstructing plant biomass by the secretion of an arsenal of plant cell wall-degrading enzymes, by remodeling metabolism to accommodate production of secreted enzymes, and by enabling transport and intracellular utilization of plant biomass components. Although a number of enzymes and transcriptional regulators involved in plant biomass utilization have been identified, how filamentous fungi sense and integrate nutritional information encoded in the plant cell wall into a regulatory hierarchy for optimal utilization of complex carbon sources is not understood. Here, we performed transcriptional profiling ofN. crassaon 40 different carbon sources, including plant biomass, to provide data on how fungi sense simple to complex carbohydrates. From these data, we identified regulatory factors inN. crassaand characterized one (PDR-2) associated with pectin utilization and one with pectin/hemicellulose utilization (ARA-1). Using in vitro DNA affinity purification sequencing (DAP-seq), we identified direct targets of transcription factors involved in regulating genes encoding plant cell wall-degrading enzymes. In particular, our data clarified the role of the transcription factor VIB-1 in the regulation of genes encoding plant cell wall-degrading enzymes and nutrient scavenging and revealed a major role of the carbon catabolite repressor CRE-1 in regulating the expression of major facilitator transporter genes. These data contribute to a more complete understanding of cross talk between transcription factors and their target genes, which are involved in regulating nutrient sensing and plant biomass utilization on a global level.


IAWA Journal ◽  
2014 ◽  
Vol 35 (2) ◽  
pp. 127-137 ◽  
Author(s):  
Shengcheng Zhai ◽  
Yoshiki Horikawa ◽  
Tomoya Imai ◽  
Junji Sugiyama

The cell wall organization of leaf sheath fibers in different palm species was studied with polarized light microscopy (PLM) and transmission electron microscopy (TEM). The secondary wall of the fibers consisted of only two layers, S1 and S2. The thickness of the S1 layer in leaf sheath fibers from the different palm species ranged from 0.31 to 0.90 μm, with a mean value of 0.57 μm, which was thicker than that of tracheids and fibers in secondary xylem of conifers and dicotyledons. The thickness of the S2 layer ranged from 0.44 to 3.43 μm, with a mean value of 1.86 μm. The ratio of S1 thickness to the whole cell wall thickness in palm fibers appears to be higher than in secondary xylem fibers and tracheids. The lignin in the fiber walls is very electron dense which makes it difficult to obtain high contrast of the different layers in the secondary wall. To clarify the cell wall layering with cellulose microfibrils in different orientations, the fibrovascular bundles of the windmill palm (Trachycarpus fortunei) were delignified with different reaction time intervals. The treated fibers were surveyed using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy analysis and TEM. The secondary fiber walls of windmill palm clearly showed only two layers at different reaction intervals with different lignin contents, even after almost all lignin was removed. We suggest that the two-layered structure in the secondary wall of palm leaf fibers, which presumably also applies to the homologous fibers in palm stems, is a specific character different from the fibers in other monocotyledons (such as bamboo and rattan) and dicot wood.


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