Forages for feedstocks of biorefineries in temperate environments: review of lignin research in bioenergy crops and some insight into Miscanthus studies

2014 ◽  
Vol 65 (11) ◽  
pp. 1199 ◽  
Author(s):  
Maria S. Dwiyanti ◽  
J. Ryan Stewart ◽  
Toshihiko Yamada
Keyword(s):  
Panicum Virgatum ◽  
Target Genes ◽  
Lignin Content ◽  
Genetic Regulation ◽  
Warm Season ◽  
Lignin Biosynthesis ◽  
Biofuel Production ◽  
Bioenergy Crops ◽  
Cost Efficient ◽  
Insight Into

Rhizomatous and perennial warm-season C4 grasses such as Miscanthus spp. and switchgrass (Panicum virgatum) are potential bioenergy crops for temperate regions. However, lignin in Miscanthus and switchgrass inhibits the cellulose digestion process during bioethanol production. One of the targets for improvement of forages from feedstocks to bioenergy crops is to develop a cost-efficient biorefinery process through lignin content manipulation. Numerous reports have shown that RNAi suppression of lignin-biosynthesis pathway genes can increase biomass fermentable sugar yields for biofuel production. These studies have also reported that RNAi suppression of cell-wall lignin biosynthesis can decrease biomass yield and resistance to biotic stress in the transgenic plants. Transcriptome and metabolome approaches can be used to clarify the networks and pathways of lignin biosynthesis to facilitate the identification of appropriate target genes for transformation. However, whole-genome sequencing of the forage species, which provides much-needed genomic information, is limited. Germplasm of natural, low-lignin mutants also plays a role in identification of genetic regulation of lignin content and this would be useful breeding material. Molecular markers have been developed and utilised to accelerate identification of quantitative trait loci/genes for traits relating to the biorefinery process. All of these studies will serve as basic information for supporting genetic improvement through classical breeding or genetic transformation, and offer the opportunity to develop cultivars which have enhanced biomass and are cost-efficient for biorefinery process.

scholarly journals Patatin-Related Phospholipase AtpPLAIIIα Affects Lignification of Xylem in Arabidopsis and Hybrid Poplars

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 451 ◽  
Author(s):  
Jin Hoon Jang ◽  
Ok Ran Lee
Keyword(s):  
Cell Walls ◽  
Lignin Content ◽  
Lignin Biosynthesis ◽  
Biofuel Production ◽  
Amide Bonds ◽  
Hybrid Poplars ◽  
Plant Lipids ◽  
Lipid Acyl Hydrolase ◽  
Specific Regulation

Lipid acyl hydrolase are a diverse group of enzymes that hydrolyze the ester or amide bonds of fatty acid in plant lipids. Patatin-related phospholipase AIIIs (pPLAIIIs) are one of major lipid acyl hydrolases that are less closely related to potato tuber patatins and are plant-specific. Recently, overexpression of ginseng-derived PgpPLAIIIβ was reported to be involved in the reduced level of lignin content in Arabidopsis and the mature xylem layer of poplar. The presence of lignin-polysaccharides renders cell walls recalcitrant for pulping and biofuel production. The tissue-specific regulation of lignin biosynthesis, without altering all xylem in plants, can be utilized usefully by keeping mechanical strength and resistance to various environmental stimuli. To identify another pPLAIII homolog from Arabidopsis, constitutively overexpressed AtpPLAIIIα was characterized for xylem lignification in two well-studied model plants, Arabidopsis and poplar. The characterization of gene function in annual and perennial plants with respect to lignin biosynthesis revealed the functional redundancy of less lignification via downregulation of lignin biosynthesis-related genes.

scholarly journals Simulated Biomass, Climate Change Impacts, and Nitrogen Management to Achieve Switchgrass Biofuel Production at Diverse Sites in U.S.

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 503 ◽  
Author(s):  
Sumin Kim ◽  
Sojung Kim ◽  
Jaepil Cho ◽  
Seonggyu Park ◽  
Fernando Xavier Jarrín Perez ◽  
...  
Keyword(s):  
Climate Change ◽  
Panicum Virgatum ◽  
Warm Season ◽  
Field Trials ◽  
N Fertilization ◽  
N Fertilizer ◽  
Future Climate ◽  
Biofuel Production ◽  
Climate Conditions ◽  
Functional Relationships

Switchgrass (Panicum virgatum L.) is a C4, warm season, perennial native grass that has been strongly recommended as an ideal biofuel feedstock. Accurate forecasting of switchgrass yield across a geographically diverse region and under future climate conditions is essential for determining realistic future ethanol production from switchgrass. This study compiled a switchgrass database through reviewing the existing literature from field trials across the U.S. Using observed switchgrass data, a process-based model (ALMANAC) was developed. The ALMANAC simulation results showed that crop management had more effect on yield than location. The ALMANAC model consists of functional relationships that provide a better understanding of interactions among plant physiological processes and environmental factors (water, soil, climate, and nutrients) giving realistic predictions in different climate conditions. This model was used to quantify the impacts of climate change on switchgrass yields. Simulated lowland switchgrass would have more yield increases between Illinois and Ohio in future (2021–2050) under both Representative Concentration Pathway (RCP) 4.5 and 8.5 pathways with low N fertilizer inputs than high N fertilizer inputs. There was no significant effect of climate variability on upland simulated yields, which means that N fertilization is a key factor in controlling upland switchgrass yields under future climate conditions.

scholarly journals Digesting the indigestible: Biosynthesis of the plant secondary wall

2011 ◽  
Vol 33 (2) ◽  
pp. 24-28
Author(s):  
Raymond Wightman ◽  
Simon Turner
Keyword(s):  
Cell Walls ◽  
Panicum Virgatum ◽  
Second Generation ◽  
Plant Biomass ◽  
Biofuel Production ◽  
Bioenergy Crops ◽  
Second Generation Biofuels ◽  
Biofuel Crops ◽  
Secondary Cell Walls ◽  
Micro Organisms

Biofuels have recently been the subject of intense debate with regard to‘food versus fuel’. Consequently, attention has focused upon so-called ‘second-generation’ biofuels that use alternatives to food-based feedstocks. In the best-developed forms of second-generation biofuels, sugars from starch digestion could be replaced with sugars released from the plant cell walls. This biomass could come from either agricultural residue, such as part of the maize culm, or from purpose grown biofuel crops, such as Miscanthus or Switchgrass (Panicum virgatum), that generate huge yields even when grown on marginal land with minimal agricultural inputs. For these and other potential bioenergy crops such as trees, the majority of the plant biomass is composed of woody secondary cell walls. If all cell wall sugars were readily accessible to fermenting micro-organisms, a 5 kg log could theoretically produce up to 2.5 litres of ethanol. The secondary cell walls are frequently the first line of defence against pests and pathogens, as well as providing structure and support for upward plant growth (Figure 1). Consequently, by their very nature, secondary cell walls are designed for strength and to resist degradation. The compact organization of the wall makes its digestion, a process known as saccharification, very difficult so biomass is currently too costly to be a viable feedstock. Knowledge of how the walls are constructed, however, would allow us to efficiently deconstruct them. This article gives an overview of secondary walls and potential modifications expected to be beneficial to improved biofuel production.

scholarly journals Expression of a bacterial 3-dehydroshikimate dehydratase (QsuB) reduces lignin and improves biomass saccharification efficiency in switchgrass (Panicum virgatum L.)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhangying Hao ◽  
Sasha Yogiswara ◽  
Tong Wei ◽  
Veronica Teixeira Benites ◽  
Anagh Sinha ◽  
...  
Keyword(s):  
Panicum Virgatum ◽  
Lignin Content ◽  
Biomass Conversion ◽  
Value Added ◽  
Bioenergy Crops ◽  
Altered Expression ◽  
Fusion Construct ◽  
Model Plant ◽  
Biomass Saccharification ◽  
Saccharification Efficiency

Abstract Background Lignin deposited in plant cell walls negatively affects biomass conversion into advanced bioproducts. There is therefore a strong interest in developing bioenergy crops with reduced lignin content or altered lignin structures. Another desired trait for bioenergy crops is the ability to accumulate novel bioproducts, which would enhance the development of economically sustainable biorefineries. As previously demonstrated in the model plant Arabidopsis, expression of a 3-dehydroshikimate dehydratase in plants offers the potential for decreasing lignin content and overproducing a value-added metabolic coproduct (i.e., protocatechuate) suitable for biological upgrading. Results The 3-dehydroshikimate dehydratase QsuB from Corynebacterium glutamicum was expressed in the bioenergy crop switchgrass (Panicum virgatum L.) using the stem-specific promoter of an O-methyltransferase gene (pShOMT) from sugarcane. The activity of pShOMT was validated in switchgrass after observation in-situ of beta-glucuronidase (GUS) activity in stem nodes of plants carrying a pShOMT::GUS fusion construct. Under controlled growth conditions, engineered switchgrass lines containing a pShOMT::QsuB construct showed reductions of lignin content, improvements of biomass saccharification efficiency, and accumulated higher amount of protocatechuate compared to control plants. Attempts to generate transgenic switchgrass lines carrying the QsuB gene under the control of the constitutive promoter pZmUbi-1 were unsuccessful, suggesting possible toxicity issues associated with ectopic QsuB expression during the plant regeneration process. Conclusion This study validates the transfer of the QsuB engineering approach from a model plant to switchgrass. We have demonstrated altered expression of two important traits: lignin content and accumulation of a co-product. We found that the choice of promoter to drive QsuB expression should be carefully considered when deploying this strategy to other bioenergy crops. Field-testing of engineered QsuB switchgrass are in progress to assess the performance of the introduced traits and agronomic performances of the transgenic plants.

scholarly journals Low Lignin Mutants and Reduction of Lignin Content in Grasses for Increased Utilisation of Lignocellulose

Agronomy ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 256 ◽  
Author(s):  
Cecilie S. L. Christensen ◽  
Søren K. Rasmussen
Keyword(s):  
Animal Feed ◽  
Lignin Content ◽  
Lignin Biosynthesis ◽  
Biofuel Production ◽  
Phenotypic Traits ◽  
Monolignol Biosynthesis ◽  
Genes Encoding ◽  
Regulated Gene Expression ◽  
Mutant Lines ◽  
The Impact

Biomass rich in lignocellulose from grasses is a major source for biofuel production and animal feed. However, the presence of lignin in cell walls limits its efficient utilisation such as in its bioconversion to biofuel. Reduction of the lignin content or alteration of its structure in crop plants have been pursued, either by regulating genes encoding enzymes in the lignin biosynthetic pathway using biotechnological techniques or by breeding naturally-occurring low lignin mutant lines. The aim of this review is to provide a summary of these studies, focusing on lignin (monolignol) biosynthesis and composition in grasses and, where possible, the impact on recalcitrance to bioconversion. An overview of transgenic crops of the grass family with regulated gene expression in lignin biosynthesis is presented, including the effect on lignin content and changes in the ratio of p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) units. Furthermore, a survey is provided of low-lignin mutants in grasses, including cereals in particular, summarising their origin and phenotypic traits together with genetics and the molecular function of the various genes identified.

scholarly journals Distinct and Overlapping Functions of Miscanthus sinensis MYB Transcription Factors SCM1 and MYB103 in Lignin Biosynthesis

2021 ◽  
Vol 22 (22) ◽  
pp. 12395
Author(s):  
Philippe Golfier ◽  
Olga Ermakova ◽  
Faride Unda ◽  
Emily K. Murphy ◽  
Jianbo Xie ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcription Factors ◽  
Secondary Cell Wall ◽  
Target Genes ◽  
Lignin Content ◽  
Ectopic Expression ◽  
Lignin Biosynthesis ◽  
Miscanthus Sinensis ◽  
Growth Stages ◽  
Transcriptional Responses

Cell wall recalcitrance is a major constraint for the exploitation of lignocellulosic biomass as a renewable resource for energy and bio-based products. Transcriptional regulators of the lignin biosynthetic pathway represent promising targets for tailoring lignin content and composition in plant secondary cell walls. However, knowledge about the transcriptional regulation of lignin biosynthesis in lignocellulosic feedstocks, such as Miscanthus, is limited. In Miscanthus leaves, MsSCM1 and MsMYB103 are expressed at growth stages associated with lignification. The ectopic expression of MsSCM1 and MsMYB103 in N. benthamiana leaves was sufficient to trigger secondary cell wall deposition with distinct sugar and lignin compositions. Moreover, RNA-seq analysis revealed that the transcriptional responses to MsSCM1 and MsMYB103 overexpression showed an extensive overlap with the response to the NAC master transcription factor MsSND1, but were distinct from each other, underscoring the inherent complexity of secondary cell wall formation. Furthermore, conserved and previously described promoter elements as well as novel and specific motifs could be identified from the target genes of the three transcription factors. Together, MsSCM1 and MsMYB103 represent interesting targets for manipulations of lignin content and composition in Miscanthus towards a tailored biomass.

scholarly journals CRISPR-Knockout of CSE Gene Improves Saccharification Efficiency by Reducing Lignin Content in Hybrid Poplar

2021 ◽  
Vol 22 (18) ◽  
pp. 9750
Author(s):  
Hyun-A Jang ◽  
Eun-Kyung Bae ◽  
Min-Ha Kim ◽  
Su-Jin Park ◽  
Na-Young Choi ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Lignin Content ◽  
Hybrid Poplar ◽  
Lignin Biosynthesis ◽  
Biofuel Production ◽  
Guide Rnas ◽  
Hybrid Poplars ◽  
Four Seasons ◽  
Promising Target ◽  
Saccharification Efficiency

Caffeoyl shikimate esterase (CSE) has been shown to play an important role in lignin biosynthesis in plants and is, therefore, a promising target for generating improved lignocellulosic biomass crops for sustainable biofuel production. Populus spp. has two CSE genes (CSE1 and CSE2) and, thus, the hybrid poplar (Populus alba × P. glandulosa) investigated in this study has four CSE genes. Here, we present transgenic hybrid poplars with knockouts of each CSE gene achieved by CRISPR/Cas9. To knockout the CSE genes of the hybrid poplar, we designed three single guide RNAs (sg1–sg3), and produced three different transgenic poplars with either CSE1 (CSE1-sg2), CSE2 (CSE2-sg3), or both genes (CSE1/2-sg1) mutated. CSE1-sg2 and CSE2-sg3 poplars showed up to 29.1% reduction in lignin deposition with irregularly shaped xylem vessels. However, CSE1-sg2 and CSE2-sg3 poplars were morphologically indistinguishable from WT and showed no significant differences in growth in a long-term living modified organism (LMO) field-test covering four seasons. Gene expression analysis revealed that many lignin biosynthetic genes were downregulated in CSE1-sg2 and CSE2-sg3 poplars. Indeed, the CSE1-sg2 and CSE2-sg3 poplars had up to 25% higher saccharification efficiency than the WT control. Our results demonstrate that precise editing of CSE by CRISPR/Cas9 technology can improve lignocellulosic biomass without a growth penalty.

scholarly journals 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 ◽  
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.

scholarly journals Targeting hydroxycinnamoyl CoA: shikimate hydroxycinnamoyl transferase for lignin modification in Brachypodium distachyon

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Juan Carlos Serrani-Yarce ◽  
Luis Escamilla-Trevino ◽  
Jaime Barros ◽  
Lina Gallego-Giraldo ◽  
Yunqiao Pu ◽  
...  
Keyword(s):  
Negative Impact ◽  
Lignin Content ◽  
Brachypodium Distachyon ◽  
Lignin Biosynthesis ◽  
Reverse Direction ◽  
Wall Structure ◽  
Kinetic Properties ◽  
Loss Of Function ◽  
Down Regulation ◽  
Lignin Modification

Abstract Background Hydroxycinnamoyl CoA: shikimate hydroxycinnamoyl transferase (HCT) is a central enzyme of the so-called “esters” pathway to monolignols. As originally envisioned, HCT functions twice in this pathway, to form coumaroyl shikimate and then, in the “reverse” direction, to convert caffeoyl shikimate to caffeoyl CoA. The discovery of a caffeoyl shikimate esterase (CSE) that forms caffeic acid directly from caffeoyl shikimate calls into question the need for the reverse HCT reaction in lignin biosynthesis. Loss of function of HCT gives severe growth phenotypes in several dicot plants, but less so in some monocots, questioning whether this enzyme, and therefore the shikimate shunt, plays the same role in both monocots and dicots. The model grass Brachypodium distachyon has two HCT genes, but lacks a classical CSE gene. This study was therefore conducted to evaluate the utility of HCT as a target for lignin modification in a species with an “incomplete” shikimate shunt. Results The kinetic properties of recombinant B. distachyon HCTs were compared with those from Arabidopsis thaliana, Medicago truncatula, and Panicum virgatum (switchgrass) for both the forward and reverse reactions. Along with two M. truncatula HCTs, B. distachyon HCT2 had the least kinetically unfavorable reverse HCT reaction, and this enzyme is induced when HCT1 is down-regulated. Down regulation of B. distachyon HCT1, or co-down-regulation of HCT1 and HCT2, by RNA interference led to reduced lignin levels, with only modest changes in lignin composition and molecular weight. Conclusions Down-regulation of HCT1, or co-down-regulation of both HCT genes, in B. distachyon results in less extensive changes in lignin content/composition and cell wall structure than observed following HCT down-regulation in dicots, with little negative impact on biomass yield. Nevertheless, HCT down-regulation leads to significant improvements in biomass saccharification efficiency, making this gene a preferred target for biotechnological improvement of grasses for bioprocessing.

THE BIOENERGY CROPS MARKET IN UKRAINE: TRENDS OF DEVELOPMENT AND SPATIAL DIFFERENTIATION

2017 ◽  
Author(s):  
Yuriy Hayda ◽  
◽  
Khrystyna Firman ◽  
Keyword(s):  
Sugar Beet ◽  
Agricultural Sector ◽  
Spatial Differentiation ◽  
Raw Material ◽  
Biofuel Production ◽  
Bioenergy Crops ◽  
Positive Trend ◽  
Energy Potential ◽  
Resource Base ◽  
Positive Tendency

In this article analyzes the development of trends of bioenergy crops market development in Ukraine and its current state are analysed. The possibility and feasibility of synergy of mutual development of bioenergy crops market and bio-oil market in Ukraine were noted. The necessity of state support and stimulation of bioenergy crops and different types of biofuels production in Ukraine was stated. A positive trend of growth of planted areas and production of rapeseed in Ukraine was revealed. During the study period (2013-2019) the production of rapeseed was increased by 1.4 times. The greatest energy potential for the production of bioethanol is in the sugar beet subcomplex of the agricultural sector. Over the past few years, the production of sugar beet was at its highest in 2014 (15.7 million tonnes), while the following years saw a decrease in cultivated areas of sugar beet and, consequently, a drop in its gross output - to 8.3 million tonnes in 2020. Significant resource potential for the production of bioethanol also have cereal crops (wheat, rye, barley, maize), the area under which during the last ten years remains relatively stable (14.4-15.3 million ha). Among grain crops the most effective raw material for the production of bioethanol is maize. A positive tendency of biennial growth of planted area under this crop is revealed. The space differentiation of resource base of bioenergy in Ukraine is prominent. The cluster analysis revealed three groups of areas based on the similarity of the energy resources for bioenergy purposes. Two clusters including Khmelnytskyi, Ternopil, Zhytomyr and Chernihiv, Vinnytsia, Cherkasy, Sumy, Kirovograd, Poltava and Kyiv regions should be considered as the most promising areas for concentration of capacities in biofuel production. It is noted that the trajectory of development bioenergetic sector of the country is always conditioned by compromise between compliance with optimal levels of its energy and food security.

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