Integrated NIRS and QTL assays reveal minor mannose and galactose as contrast lignocellulose factors for biomass enzymatic saccharification in rice

Abstract Background Identifying lignocellulose recalcitrant factors and exploring their genetic properties are essential for enhanced biomass enzymatic saccharification in bioenergy crops. Despite genetic modification of major wall polymers has been implemented for reduced recalcitrance in engineered crops, it could most cause a penalty of plant growth and biomass yield. Alternatively, it is increasingly considered to improve minor wall components, but an applicable approach is required for efficient assay of large population of biomass samples. Hence, this study collected total of 100 rice straw samples and characterized all minor wall monosaccharides and biomass enzymatic saccharification by integrating NIRS modeling and QTL profiling. Results By performing classic chemical analyses and establishing optimal NIRS equations, this study examined four minor wall monosaccharides and major wall polymers (acid-soluble lignin/ASL, acid-insoluble lignin/AIL, three lignin monomers, crystalline cellulose), which led to largely varied hexoses yields achieved from enzymatic hydrolyses after two alkali pretreatments were conducted with large population of rice straws. Correlation analyses indicated that mannose and galactose can play a contrast role for biomass enzymatic saccharification at P < 0.0 l level (n = 100). Meanwhile, we found that the QTLs controlling mannose, galactose, lignin-related traits, and biomass saccharification were co-located. By combining NIRS assay with QTLs maps, this study further interpreted that the mannose-rich hemicellulose may assist AIL disassociation for enhanced biomass enzymatic saccharification, whereas the galactose-rich polysaccharides should be effectively extracted with ASL from the alkali pretreatment for condensed AIL association with cellulose microfibrils. Conclusions By integrating NIRS assay with QTL profiling for large population of rice straw samples, this study has identified that the mannose content of wall polysaccharides could positively affect biomass enzymatic saccharification, while the galactose had a significantly negative impact. It has also sorted out that two minor monosaccharides could distinctively associate with lignin deposition for wall network construction. Hence, this study demonstrates an applicable approach for fast assessments of minor lignocellulose recalcitrant factors and biomass enzymatic saccharification in rice, providing a potential strategy for bioenergy crop breeding and biomass processing.

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Integrated NIRS and QTL assays reveal minor mannose and galactose as contrast lignocellulose factors for biomass enzymatic saccharification in rice

10.21203/rs.3.rs-341409/v1 ◽

2021 ◽

Author(s):

Zhen Hu ◽

You Mei Wang ◽

Jingyuan Liu ◽

Yuqi Li ◽

Yan Ting Wang ◽

...

Keyword(s):

Rice Straw ◽

Negative Impact ◽

Large Population ◽

Enzymatic Saccharification ◽

Cellulose Microfibrils ◽

Bioenergy Crops ◽

Crystalline Cellulose ◽

Biomass Saccharification ◽

Acid Soluble Lignin ◽

Potential Strategy

Abstract Background: Identifying lignocellulose recalcitrant factors and exploring their genetic properties are essential for enhanced biomass enzymatic saccharification in bioenergy crops. Despite genetic modification of major wall polymers has been implemented for reduced recalcitrance in engineered plant, it could most cause a penalty of plant growth and biomass yield. Alternatively, it is increasingly considered to improve minor wall components, but an applicable approach is required for efficient assay of large population of biomass samples. Hence, this study collected total 100 rice straw samples and characterized all minor wall monosaccharides and biomass enzymatic saccharification by integrating NIRS modeling and QTL profiling. Results: By performing classic chemical analyses and establishing optimal NIRS equations, this study examined a diversity of four minor wall monosaccharides and major wall polymers (acid-soluble lignin/ASL, acid-insoluble lignin/AIL, three lignin monomers, crystalline cellulose), which led to largely varied hexoses yields achieved from enzymatic hydrolyses after two alkali pretreatments were conducted with all rice straws. Correlation analyses indicated that mannose and galactose could play a contrast role for biomass enzymatic saccharification at P < 0.0l level (n=100). Meanwhile, this study found that QTLs controlling mannose, galactose, lignin-related traits and biomass saccharification were co-located. Notably, by combining NIRS assay with QTLs maps, this study interpreted that the mannose-rich hemicellulose may assist AIL disassociation for enhanced biomass enzymatic saccharification, whereas the galactose-rich polysaccharides should be effectively extracted with ASL from alkali pretreatment for condensed AIL association with cellulose microfibrils against enzymatic hydrolysis. Conclusions: By integrating NIRS assay with QTL profiling for large population of rice straw samples, this study identified that the mannose of wall polysaccharides could positively affect biomass enzymatic saccharification, whereas the galactose had a significantly negative impact. It also sorted out that two minor monosaccharides should distinctively associate with lignin deposition for wall network construction. Hence, this study has demonstrated an applicable approach for fast assessments of minor lignocellulose recalcitrant factors and biomass enzymatic saccharification in rice, and it has also provided a potential strategy for bioenergy crop breeding.

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Diverse Banana Pseudostems and Rachis Are Distinctive for Edible Carbohydrates and Lignocellulose Saccharification towards High Bioethanol Production under Chemical and Liquid Hot Water Pretreatments

Molecules ◽

10.3390/molecules26133870 ◽

2021 ◽

Vol 26 (13) ◽

pp. 3870

Author(s):

Jingyang Li ◽

Fei Liu ◽

Hua Yu ◽

Yuqi Li ◽

Shiguang Zhou ◽

...

Keyword(s):

Soluble Sugars ◽

Enzymatic Saccharification ◽

Hot Water ◽

Biofuel Production ◽

Bioenergy Crops ◽

Bioethanol Production ◽

Factors Affecting ◽

Liquid Hot Water ◽

Biomass Processing ◽

Banana Crops

Banana is a major fruit crop throughout the world with abundant lignocellulose in the pseudostem and rachis residues for biofuel production. In this study, we collected a total of 11 pseudostems and rachis samples that were originally derived from different genetic types and ecological locations of banana crops and then examined largely varied edible carbohydrates (soluble sugars, starch) and lignocellulose compositions. By performing chemical (H2SO4, NaOH) and liquid hot water (LHW) pretreatments, we also found a remarkable variation in biomass enzymatic saccharification and bioethanol production among all banana samples examined. Consequently, this study identified a desirable banana (Refen1, subgroup Pisang Awak) crop containing large amounts of edible carbohydrates and completely digestible lignocellulose, which could be combined to achieve the highest bioethanol yields of 31–38% (% dry matter), compared with previously reported ones in other bioenergy crops. Chemical analysis further indicated that the cellulose CrI and lignin G-monomer should be two major recalcitrant factors affecting biomass enzymatic saccharification in banana pseudostems and rachis. Therefore, this study not only examined rich edible carbohydrates for food in the banana pseudostems but also detected digestible lignocellulose for bioethanol production in rachis tissue, providing a strategy applicable for genetic breeding and biomass processing in banana crops.

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A semi-dominant mutation in OsCESA9 improves rice straw return to the field and increases salt tolerance by remodeling the cell wall in rice

10.21203/rs.3.rs-63488/v1 ◽

2020 ◽

Author(s):

Yafeng Ye ◽

Shuoxun Wang ◽

Kun Wu ◽

Yan Ren ◽

Hongrui Jiang ◽

...

Keyword(s):

Salt Tolerance ◽

Plant Growth ◽

Rice Straw ◽

Enzymatic Saccharification ◽

Cellulose Content ◽

Normal Plant ◽

Wild Type ◽

Negative Effects ◽

Biomass Saccharification ◽

Straw Return

Abstract Background Cellulose synthase (CESA) mutants have potential use in straw processing due to their lower cellulose content, but almost all of the mutants exhibit defective phenotypes in plant growth and development. Balancing normal plant growth with reduced cellulose content remains a challenge, as cellulose content and normal plant growth are typically negatively correlated with one another.Result Here, the rice (Oryza sativa) semi-dominant brittle culm (sdbc) mutant Sdbc1, which harbors a substitution (D387N) at the first conserved aspartic acid residue of OsCESA9, exhibits lower cellulose content and reduced secondary wall thickness as well as enhanced biomass enzymatic saccharification compared with the wild type. Further experiments indicated that the OsCESA9D387N mutation may compete with the wild-type OsCESA9 for interacting with OsCESA4 and OsCESA7, further forming non-functional or partially functional CSCs. The OsCESA9/OsCESA9D387N heterozygous plants increase salt tolerance through scavenging and detoxification of ROS and indirectly affecting related gene expression. They also improve rice straw return to the field due to their brittle culms and lower cellulose content without any negative effects in grain yield and lodging.Conclusion Hence, manipulation of OsCESA9D387N can enhance biomass saccharification and simultaneously facilitate the decay of rice straw in the soil, providing a new strategy for bioenergy crop breeding.

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Thermogravimetric analysis-based characterization of suitable biomass for alkaline peroxide treatment to obtain cellulose and fermentable sugars

BioResources ◽

10.15376/biores.15.3.6217-6229 ◽

2020 ◽

Vol 15 (3) ◽

pp. 6217-6229

Author(s):

Akihiro Hideno

Keyword(s):

Thermogravimetric Analysis ◽

Thermal Degradation ◽

Rice Straw ◽

Lignin Content ◽

Cellulose Microfibrils ◽

Crystalline Cellulose ◽

Japanese Cypress ◽

Alkaline Peroxide ◽

Degradation Temperature ◽

Thermal Degradation Temperature

To characterize a suitable biomass for alkaline peroxide treatment, four types of lignocellulosic biomass (rice straw, two Miscanthus spp., and Japanese cypress) were characterized using thermogravimetric analysis. Before the alkaline peroxide treatment, rice straw had the lowest initial thermal degradation temperature and Japanese cypress had the highest. After alkaline peroxide treatment, this trend was reversed, such that the highest initial thermal degradation temperature was for alkaline-peroxide treated rice straw. Hemicellulose and lignin content significantly affected the thermal degradation behavior and alkaline peroxide treatment efficiency. Among the four lignocelluloses, raw rice straw exhibited the highest reducing capability, whereas the treated rice straw exhibited the lowest reducing capability. Surface morphology and crystallinity indicated that when the rice straw was subjected to AP treatment at room temperature for 10 min, crystalline cellulose microfibrils were exposed and concentrated on the surface. Thus, among the samples tested, rice straw was found to be the most suitable biomass for alkaline peroxide treatment.

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Overexpression of the rice BAHD acyltransferase AT10 increases xylan-bound p-coumarate and reduces lignin in Sorghum bicolor

Biotechnology for Biofuels ◽

10.1186/s13068-021-02068-9 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Yang Tian ◽

Chien-Yuan Lin ◽

Joon-Hyun Park ◽

Chuan-Yin Wu ◽

Ramu Kakumanu ◽

...

Keyword(s):

Cell Wall ◽

Sorghum Bicolor ◽

Cell Walls ◽

Lignin Content ◽

Complex Structure ◽

Enzymatic Saccharification ◽

Cellulose Microfibrils ◽

Biomass Composition ◽

Bioenergy Crops ◽

Transgenic Lines

Abstract Background The development of bioenergy crops with reduced recalcitrance to enzymatic degradation represents an important challenge to enable the sustainable production of advanced biofuels and bioproducts. Biomass recalcitrance is partly attributed to the complex structure of plant cell walls inside which cellulose microfibrils are protected by a network of hemicellulosic xylan chains that crosslink with each other or with lignin via ferulate (FA) bridges. Overexpression of the rice acyltransferase OsAT10 is an effective bioengineering strategy to lower the amount of FA involved in the formation of cell wall crosslinks and thereby reduce cell wall recalcitrance. The annual crop sorghum represents an attractive feedstock for bioenergy purposes considering its high biomass yields and low input requirements. Although we previously validated the OsAT10 engineering approach in the perennial bioenergy crop switchgrass, the effect of OsAT10 expression on biomass composition and digestibility in sorghum remains to be explored. Results We obtained eight independent sorghum (Sorghum bicolor (L.) Moench) transgenic lines with a single copy of a construct designed for OsAT10 expression. Consistent with the proposed role of OsAT10 in acylating arabinosyl residues on xylan with p-coumarate (pCA), a higher amount of p-coumaroyl-arabinose was released from the cell walls of these lines upon hydrolysis with trifluoroacetic acid. However, no major changes were observed regarding the total amount of pCA or FA esters released from cell walls upon mild alkaline hydrolysis. Certain diferulate (diFA) isomers identified in alkaline hydrolysates were increased in some transgenic lines. The amount of the main cell wall monosaccharides glucose, xylose, and arabinose was unaffected. The transgenic lines showed reduced lignin content and their biomass released higher yields of sugars after ionic liquid pretreatment followed by enzymatic saccharification. Conclusions Expression of OsAT10 in sorghum leads to an increase of xylan-bound pCA without reducing the overall content of cell wall FA esters. Nevertheless, the amount of total cell wall pCA remains unchanged indicating that most pCA is ester-linked to lignin. Unlike other engineered plants overexpressing OsAT10 or a phylogenetically related acyltransferase with similar putative function, the improvements of biomass saccharification efficiency in sorghum OsAT10 lines are likely the result of lignin reductions rather than reductions of cell wall-bound FA. These results also suggest a relationship between xylan-bound pCA and lignification in cell walls.

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Efficiency of Corn and Poplar Biomass Saccharification after Pretreatment with Potassium Hydroxide

Ecological Chemistry and Engineering S ◽

10.2478/eces-2020-0002 ◽

2020 ◽

Vol 27 (1) ◽

pp. 41-53

Author(s):

Katarzyna Dąbkowska-Susfał

Keyword(s):

Lignocellulosic Biomass ◽

Potassium Hydroxide ◽

Enzymatic Saccharification ◽

Biomass Composition ◽

Poplar Wood ◽

Corn Straw ◽

Biomass Saccharification ◽

Biomass Processing ◽

Lignocellulosic Feedstocks ◽

Pretreatment Time

AbstractPretreatment is an essential step in the conversion of lignocellulosic biomass into valuable products. It aims to increase the biomass susceptibility to enzymatic saccharification to generate fermentable monosaccharides. In this study, the efficiency of 2 % potassium hydroxide (KOH) solution used as a pretreating agent for various lignocellulosic feedstocks, such as corn straw, corncob, and poplar wood, was evaluated. The influence of the pretreatment time, which varied from 0.5 to 24 h at 50 °C, on the alteration of biomass composition was investigated, as well as the enzymatic digestibility. Finally, the overall sugar yields were determined. For corncob, the yield on average amounted to 453.9 ±18.9 mg·g−1 raw (untreated) biomass, regardless of the pretreatment time. The overall sugar yield for both the corn straw and poplar wood biomass increased with increased pretreatment time and ranged from 333.0 to 438.4 mg·g−1 raw biomass and from 123.2 to 215.7 mg·g−1 raw biomass, respectively. Based on the results obtained, the most appropriate pretreatment times for all types of biomass were proposed. The results of this study may be useful for the development of lignocellulosic biomass processing technology.

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A novel predictive method for filler coflocculation with cellulose microfibrils

TAPPI Journal ◽

10.32964/tj18.11.653 ◽

2019 ◽

Vol 18 (11) ◽

pp. 653-664

Author(s):

IGNACIO DE SAN PIO ◽

KLAS G. JOHANSSON ◽

PAUL KROCHAK

Keyword(s):

Negative Impact ◽

High Strength ◽

Strength Properties ◽

Cellulose Microfibrils ◽

Paper Strength ◽

Flow Loop ◽

Cationic Starch ◽

Reflectance Measurement ◽

Drainage Rate ◽

Complete Study

Different strategies aimed at reducing the negative impact of fillers on paper strength have been the objective of many studies during the past few decades. Some new strategies have even been patented or commercialized, yet a complete study on the behavior of the filler flocs and their effect on retention, drainage, and formation has not been found in literature. This type of research on fillers is often limited by difficulties in simulating high levels of shear at laboratory scale similar to those at mill scale. To address this challenge, a combination of techniques was used to compare preflocculation (i.e., filler is flocculated before addition to the pulp) with coflocculation strategies (i.e., filler is mixed with a binder and flocculated before addition to the pulp). The effect on filler and fiber flocs size was studied in a pilot flow loop using focal beam reflectance measurement (FBRM) and image analysis. Flocs obtained with cationic polyacrylamide (CPAM) and bentonite were shown to have similar shear resistance with both strategies, whereas cationic starch (CS) was clearly more advantageous when coflocculation strategy was used. The effect of flocculation strategy on drainage rate, STFI formation, ash retention, and standard strength properties was measured. Coflocculation of filler with CPAM plus bentonite or CS showed promising results and produced sheets with high strength but had a negative impact on wire dewatering, opening a door for further optimization.

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Comparison of Corn Stover Pretreatments with Lewis Acid Catalyzed Choline Chloride, Glycerol and Choline Chloride-Glycerol Deep Eutectic Solvent

Polymers ◽

10.3390/polym13071170 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1170

Author(s):

Yuan Zhu ◽

Benkun Qi ◽

Xinquan Liang ◽

Jianquan Luo ◽

Yinhua Wan

Keyword(s):

Corn Stover ◽

Lewis Acid ◽

Choline Chloride ◽

Deep Eutectic Solvent ◽

Enzymatic Saccharification ◽

Glycerol Solution ◽

Cellulose Conversion ◽

Biomass Processing ◽

Acid Catalyzed ◽

Highly Correlated

Herein, corn stover (CS) was pretreated by less corrosive lewis acid FeCl3 acidified solutions of neat and aqueous deep eutectic solvent (DES), aqueous ChCl and glycerol at 120 °C for 4 h with single FeCl3 pretreatment as control. It was unexpected that acidified solutions of both ChCl and glycerol were found to be more efficient at removing lignin and xylan, leading to higher enzymatic digestibility of pretreated CS than acidified DES. Comparatively, acidified ChCl solution exhibited better pretreatment performance than acidified glycerol solution. In addition, 20 wt% water in DES dramatically reduced the capability of DES for delignification and xylan removal and subsequent enzymatic cellulose saccharification of pretreated CS. Correlation analysis showed that enzymatic saccharification of pretreated CS was highly correlated to delignification and cellulose crystallinity, but lowly correlated to xylan removal. Recyclability experiments of different acidified pretreatment solutions showed progressive decrease in the pretreatment performance with increasing recycling runs. After four cycles, the smallest decrease in enzymatic cellulose conversion (22.07%) was observed from acidified neat DES pretreatment, while the largest decrease (43.80%) was from acidified ChCl pretreatment. Those findings would provide useful information for biomass processing with ChCl, glycerol and ChCl-glycerol DES.

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