Highest Sugar Yield Research Articles

Taguchi-assisted multi-response improved simultaneous nanocellulose and sugar production from microcrystalline cellulose derived from raw oil palm leaves

Enzymatic treatment on lignocellulosic biomass has become a trend in preparing nanocellulose (NC), but the process must be optimized to guarantee high production yield and crystallinity. This study offers insights into an innovative protocol using cultivated fungal cellulase and xylanase to improve NC production from raw oil palm leaves (OPL) using five-factor-four-level Taguchi orthogonal design for optimizing parameters, namely substrate and enzyme loading, surfactant concentration, incubation temperature and time. Statistical results revealed the best condition for producing NC (66.06 % crystallinity, 43.59 % yield) required 10 % (w/v) substrate, 1 % (v/v) enzyme, 1.4 % (w/v) Tween-80, with 72-h incubation at 30 °C. Likewise, the highest sugar yield (47.07 %) was obtained using 2.5 % (w/v) substrate, 2.0 % (v/v) enzyme, 2.0 % (w/v) Tween-80, with 72-h incubation at 60 °C. The auxiliary enzymes used in this study, i.e., xylanase, produced higher crystallinity NC, showing widths between 8 and 12 nm and lengths >1 μm and sugars at 47.07 % yield. Thus, our findings proved that optimizing the single-step enzymatic hydrolysis of raw OPL could satisfactorily produce relatively crystalline NC and sugar yield for further transformation into bio-nanocomposites and biofuels. This study presented a simple, innovative protocol for NC synthesis showing characteristics comparable to the traditionally-prepared NC, which is vital for material's commercialization.

Genotype by environment interaction and stability analysis for harvest date in sugar beet cultivars

This research assessed the quantitative and qualitative reactions of commercially grown sugar beets to four different harvest dates and their yield stability. The study followed a split-plot design within a randomized complete block design over 3 years. The main plot involved 10 sugar beet cultivars, while the subplot involved four harvest dates: August 13 (HD1), September 7 (HD2), October 3 (HD3), and November 12 (HD4). The study found that environmental conditions, genotypes, and harvest dates significantly affected various traits of sugar beet. Yearly environmental variations and their interactions with genotypes and harvest dates had substantial impacts on all measured traits at the 1% probability level. Additive main effect and multiplicative interaction analysis based on white sugar yield indicated that genotype and environment's additive effects, as well as the genotype–environment interaction, were significant at 1% probability level. Shokoufa and Arya, which exhibit high white sugar yield (WSY) and low first interaction principal component (IPC1) values, are identified as desirable due to their stability across different environments. Among the harvest dates in different years, the fourth and third dates showed a higher yield than the total average. Perfekta and Ekbatan exhibited high specific adaptability. According to the multi-trait stability index, Arta, Arya and Sina were recognized as stable and superior across all measured traits.

Biorefinery of red seaweed Palmaria palmata for production of bio-based chemicals and biofuels

The seaweed Palmaria palmata was used as feedstock for production of chemical/fuel precursors (acetone, butanol, ethanol) and biogas. Palmaria palmata consists of xylan as major cell wall polysaccharide, as well as galactan and glucan. First, the biomass was subjected to acid hydrolysis at laboratory scale to solubilise fermentable sugars using acetic or hydrochloric acid as catalysts. Differences were observed in composition and amenability to hydrolysis of seaweeds from different harvests. Highest saccharification yields were obtained using HCl (pH 1.7, 120 °C, up to 80 % of xylose). Hydrolysates were fermented to acetone-butanol-ethanol by Clostridium beijerinckii reaching yields of 0.28 g products/g consumed sugars. The process by-products (solids after acetic acid hydrolysis and spent fermentation broth) were used as feedstocks for anaerobic digestion showing biogas yields between 310 and 650 L/kg dry organic material when mixed in different ratios with sugar beet pulp. Subsequently, the hydrolysis and fermentation processes were upscaled up to a 100-L pilot volume where nanofiltration was implemented to increase sugar concentration and remove salts. While high monomeric sugar yields were replicated during upscaling, fermentation inhibition was observed in the upscaled process. This paper shows Palmaria palmata to be a suitable feedstock for the co-production of bio-butanol and biogas and highlights process development needs to desalt and detoxify seaweed hydrolysates prior to fermentation.

Stepwise processing strategy for efficient and comprehensive utilization of sugarcane bagasse via enzymatic hydrolysis and catalytic conversion to produce 5-hydroxymethylfurfural

To achieve the goal of “no waste” in circular bioeconomy on the basis of waste-to-energy conversion, the development of efficient technology for sustainable treatment and utilization of lignocellulosic biomass is significant yet challenging. In this study, a stepwise processing strategy based on enzymatic hydrolysis and catalytic conversion was proposed for comprehensive utilization of sugarcane bagasse (SCB) to produce value-added products. Mechanical activation (MA) pretreatment was adopted to disrupt the recalcitrant structure of SCB for improving enzymatic hydrolysis of polysaccharides to produce reducing sugars, obtaining a high yield (392 mg/g SCB) of target sugars (TS; i.e., cellobiose and glucose). The enzymolysis residue and Al(NO3)3·9 H2O were treated by MA and then calcinated to construct the biochar (BC)-based catalyst (denoted as MA-Al/BC) with Brønsted–Lewis dual-acidic sites, which effectively catalyzed the conversion of TS to produce 5-hydroxymethylfurfural (5-HMF). A TS conversion of 94.5% and a 5-HMF yield of 77.6% were achieved at 190 °C for 4 h in the biphasic system. MA-Al/BC exhibited excellent universality for efficient catalytic conversion of various carbohydrates. This study offers a promising approach for value-added exploitation of agricultural wastes within circular bioeconomy principles.

Development of an Integrated Bioprocess System for Bioethanol and Arabitol Production from Sugar Beet Cossettes.

An innovative integrated bioprocess system for bioethanol production from raw sugar beet cossettes (SBC) and arabitol from remaining exhausted sugar beet cossettes (ESBC) was studied. This integrated three-stage bioprocess system is an example of the biorefinery concept to maximise the use of raw SBC for the production of high value-added products such as sugar alcohols and bioethanol. The first stage of the integrated bioprocess system was simultaneous sugar extraction from SBC and its alcoholic fermentation to produce bioethanol in an integrated bioreactor system (vertical column bioreactor and stirred tank bioreactor) containing a high-density suspension of yeast Saccharomyces cerevisiae (30 g/L). The second stage was the pretreatment of ESBC with dilute sulfuric acid to release fermentable sugars. The resulting liquid hydrolysate of ESBC was used in the third stage as a nutrient medium for arabitol production by non-Saccharomyces yeasts (Spathaspora passalidarum CBS 10155 and Spathaspora arborariae CBS 11463). The obtained results show that the efficiency of bioethanol production increased with increasing temperature and prolonged residence time in the integrated bioreactor system. The maximum bioethanol production efficiency (87.22 %) was observed at a time of 60 min and a temperature of 36 °C. Further increase in residence time (above 60 min) did not result in the significant increase of bioethanol production efficiency. Weak acid hydrolysis was used for ESBC pretreatment and the highest sugar yield was reached at 200 °C and residence time of 1 min. The inhibitors of the weak acid pretreatment were produced below bioprocess inhibition threshold. The use of the obtained liqiud phase of ESBC hydrolysate for the production of arabitol in the stirred tank bioreactor under constant aeration clearly showed that S. passalidarum CBS 10155 with 8.48 g/L of arabitol (YP/S=0.603 g/g and bioprocess productivity of 0.176 g/(L.h)) is a better arabitol producer than Spathaspora arborariae CBS 10155. An innovative integrated bioprocess system for the production of bioethanol and arabitol was developed based on the biorefinery concept. This three-stage bioprocess system shows great potential for maximum use of SBC as a feedstock for bioethanol and arabitol production and it could be an example of a sustainable 'zero waste' production system.

Enhancing biomass conservation and enzymatic hydrolysis of sweet sorghum bagasse by combining pretreatment with ensiling and NaOH.

Lignocellulosic pretreatment is an important stage in biomass utilization, which usually requires high input. In this study, a low-cost method using combined ensiling and NaOH was developed for lignocellulosic pretreatment. Sweet sorghum bagasse (SSB) was ensiled for 21 days and then treated with diluted NaOH (0%, 1%, and 2%) for fermentation. The results showed that the application of Lactobacillus plantarum (L) reduced fermentation losses of the silages, mainly low water-soluble carbohydrate (WSC) and ammonia nitrogen loss. Meanwhile, the application of Lactobacillus plantarum and ensiling enzyme (LE) promoted lignocellulosic degradation, as evidenced by low neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin (ADL), and hemicellulosic (HC) contents. The dominant bacterial genera were Lactobacillus, uncultured_bacterium_f_Enterobacteriaceae, and Pantoea after silage, which corresponded to the higher lactic acid and acetic contents and lower pH. The reducing sugar yields of SSB increased after combined pretreatment of silage and NaOH and were further enhanced by the 2% NaOH application, as evidenced by the high reducing sugar yield and microstructure damage, especially in the L-2% NaOH group and the LE-2% NaOH group, in which the reducing sugar yields were 87.99 and 94.45%, respectively, compared with those of the no additive control (CK)-0 NaOH group. Therefore, this study provides an effective method for SSB pretreatment to enhance biomass conservation.

Enhancement of cellulolytic enzyme production from intrageneric protoplast fusion of Aspergillus species and evaluating the hydrolysate scavenging activity

BackgroundLignocellulosic biomass provides a great starting point for the production of energy, chemicals, and fuels. The major component of lignocellulosic biomass is cellulose, the employment of highly effective enzymatic cocktails, which can be produced by a variety of microorganisms including species of the genus Aspergillus, is necessary for its utilization in a more productive manner. In this regard, molecular biology techniques should be utilized to promote the economics of enzyme production, whereas strategies like protoplast fusion could be employed to improve the efficacy of the hydrolytic process.ResultsThe current study focuses on cellulase production in Aspergillus species using intrageneric protoplast fusion, statistical optimization of growth parameters, and determination of antioxidant activity of fermentation hydrolysate. Protoplast fusion was conducted between A. flavus X A. terreus (PFFT), A. nidulans X A. tamarii (PFNT) and A. oryzae X A. tubingensis (PFOT), and the resultant fusant PFNT revealed higher activity level compared with the other fusants. Thus, this study aimed to optimize lignocellulosic wastes-based medium for cellulase production by Aspergillus spp. fusant (PFNT) and studying the antioxidant effect of fermentation hydrolysate. The experimental strategy Plackett-Burman (PBD) was used to assess how culture conditions affected cellulase output, the best level of the three major variables namely, SCB, pH, and incubation temperature were then determined using Box-Behnken design (BBD). Consequently, by utilizing an optimized medium instead of a basal medium, cellulase activity increased from 3.11 U/ml to 7.689 U/ml CMCase. The following medium composition was thought to be ideal based on this optimization: sugarcane bagasse (SCB), 6.82 gm; wheat bran (WB), 4; Moisture, 80%; pH, 4; inoculum size, (3 × 106 spores/ml); and incubation Temp. 31.8 °C for 4 days and the fermentation hydrolysate has 28.13% scavenging activities.ConclusionThe results obtained in this study demonstrated the significant activity of the selected fusant and the higher sugar yield from cellulose hydrolysis over its parental strains, suggesting the possibility of enhancing cellulase activity by protoplast fusion using an experimental strategy and the fermentation hydrolysate showed antioxidant activity.

Production of sugars from lignocellulosic biomass via biochemical and thermochemical routes

Sugars are precursors to the majority of the world’s biofuels. Most of these come from sugar and starch crops, such as sugarcane and corn grain. Lignocellulosic sugars, although more challenging to extract from biomass, represent a large, untapped, opportunity. In response to the increasing attention to renewable energy, fuels, and chemicals, we review and compare two strategies for extracting sugars from lignocellulosic biomass: biochemical and thermochemical processing. Biochemical processing based on enzymatic hydrolysis has high sugar yield but is relatively slow. Thermochemical processing, which includes fast pyrolysis and solvent liquefaction, offers increased throughput and operability at the expense of low sugar yields.

Bioprospecting CAZymes repertoire of Aspergillus fumigatus for eco-friendly value-added transformations of agro-forest biomass

BackgroundValorizing waste residues is crucial to reaching sustainable development goals and shifting from a linear fossil-based economy to a circular economy. Fungal cell factories, due to their versatility and robustness, are instrumental in driving the bio-transformation of waste residues. The present work isolated a potent strain, i.e., Aspergillus fumigatus (ZS_AF), from an ancient Złoty Stok gold mine, which showcased distinctive capabilities for efficient hydrolytic enzyme production from lignocellulosic wastes.ResultsThe present study optimized hydrolytic enzyme production (cellulases, xylanases, and β-glucosidases) from pine sawdust (PSD) via solid-state fermentation using Aspergillus fumigatus (ZS_AF). The optimization, using response surface methodology (RSM), produced a twofold increase with maximal yields of 119.41 IU/gds for CMCase, 1232.23 IU/gds for xylanase, 63.19 IU/gds for β-glucosidase, and 31.08 IU/gds for FPase. The secretome profiling validated the pivotal role of carbohydrate-active enzymes (CAZymes) and auxiliary enzymes in biomass valorization. A total of 77% of carbohydrate-active enzymes (CAZymes) were constituted by glycoside hydrolases (66%), carbohydrate esterases (9%), auxiliary activities (3%), and polysaccharide lyases (3%). The saccharification of pretreated wheat straw and PSD generated high reducing sugar yields of 675.36 mg/g and 410.15 mg/g, respectively.ConclusionThese findings highlight the significance of an efficient, synergistic, and cost-effective arsenal of fungal enzymes for lignocellulosic waste valorization and their potential to contribute to waste-to-wealth creation through solid-waste management. The utilization of Aspergillus fumigatus (ZS_AF) from an unconventional origin and optimization strategies embodies an innovative approach that holds the potential to propel current waste valorization methods forward, directing the paradigm toward improved efficiency and sustainability.

Accounting of physical qualities of root crops during sugar beet reception and storage

This article studied the quality of sugar beet roots during storage. The determining factor in the efficiency of beet sugar production is the output of sugar at a plant. Root crops are characterized by a sharp change in technological quality depending on the areas of beet seeding, agrometeorological conditions of a year, cultivation technology and storage conditions. They are easily damaged during harvesting and transportation, they are relatively poorly stored. The physical properties of root crops depend mainly on the settings of the beet harvesters, weather conditions during the harvesting period; chemical properties depend on the varietal characteristics and agricultural cultivation techniques. When growing under the same conditions, varietal characteristics play a decisive role in the yield and technological quality of root crops. Therefore it is important to use two or three hybrids when growing on the farm, which belong to different groups according to the initial technological qualities and the level of sugar loss during storage. The hybrids must provide a high sugar yield during the sugar factory operation. Therefore, it is necessary to have hybrid-specific data on sugar yield during the entire harvesting period, the date of achieving maximum sugar content, resistance to gray rot and the intensity of sugar loss during the storage. Root crops with higher sugar content lose more sugar during prolonged storage, and its yield is reduced to a greater extent. Root crops of such hybrids should not be stored, but immediately sent for processing. Studies show that in piles where raw materials with 9–10 % of mechanically damaged root crops are stored, rotting processes are activated 4.5 times, and with 17– 18 % – 10 times faster compared to undamaged ones. To reduce the damage to root crops by gray rot during storage, biocidal preparations should be used. During storage in the field in open piles for 12 days, sugar losses in root crops reach 1.7 % in September in absolute weight. Sugar losses in such conditions reach 1.3 % in September and 0.9 % in October. The increased amount of green mass reduces the technological quality of root crops. For each per cent of green mass without storage, sugar yield is reduced by 0.2 %, molasses yield and sugar losses increase due to additional non-sugars in the juice. During storage such root crops germinate quickly, which reduces sugar yield. Key words: sugar beet, root crop, root crops quality, premature seeding, gray rot, piles.

Efficient and accurate fractionation of eucalyptus using glycolic acid-catalyzed hydrothermal treatment and alkali treatment comprehensive technology

The effective utilization of lignocellulosic biomass is the key to evaluating the profitability of the process, and precise fractionation is a prerequisite for effective utilization. In this study, a high yield of fermentable sugars and lignin rich in phenolic hydroxyl groups were successfully obtained from eucalyptus using glycolic acid-catalyzed hydrothermal and alkaline treatment. The results showed that 88.20% of xylan and 85.07% of lignin were separated, and 62.68% of lignin was extracted from the hydrolysate. The extracted lignin has a complete structure and is rich in guaiacyl and syringyl units, which is conducive to the subsequent high-value utilization of lignin. 85% of glucan was recovered, and the glucose conversion yield was 84.24% after enzymatic hydrolysis. The hydrolysate can be concentrated, impurity removed, and purified to produce biofuels or chemicals after the precipitation of lignin. In summary, the two-step process based on glycolic acid has great potential in converting eucalyptus into biomass energy and chemicals, and this process is a promising precision fractionation strategy.

Highly-efficient lipid production from hydrolysate of Radix paeoniae alba residue by oleaginous yeast Cutaneotrichosporon oleaginosum

Valorization of herbal extraction residues (HERs) into value-added products is pivotal for the sustainability of Chinese medicine industry. Here, seven different enzymatic hydrolysates of dilute acid pretreated HERs were evaluated for lipid production by Cutaneotrichosporon oleaginosum. Among them, the highest sugar yield via hydrolysis and the maximum lipid production were obtained from Radix paeoniae alba residue (RPAR). More interestingly, high proportion of sugar polymers was disintegrated into fermentable sugars during the pretreatment step, allowing a cheap non-enzymatic route for producing sugars from RPAR. A repeated dilute acid pretreatment gained a high sugar concentration of 241.6 g/L through reusing the pretreatment liquor (PL) for four times. Biomass, lipid concentration, and lipid content achieved 49.5 g/L, 35.7 g/L and 72.2 %, respectively, using fed-batch culture of PL. The biodiesel parameters indicated lipids produced from HERs were suitable for biodiesel production. This study offers a cost-effective way to upgrade the HERs waste into micro-biodiesel.

Designing of recombinant hydrolytic enzymes cocktail for effective saccharification of delignified rice straw

Enzymatic saccharification is the most crucial and challenging step in lignocellulosic biorefineries for bioethanol production. The enzymatic saccharification requires a cocktail of hydrolytic enzymes, cellulases and hemicellulases for effective degradation of biomass. However, the complete bioconversion of biomass is governed by the proportion and synergistic action of hydrolytic enzymes present in the cocktail. Thus, this study aims to formulate an enzyme cocktail consisting of recombinant cellulases (bifunctional cellulolytic chimeric enzyme, CtGH1-L1-CtGH5-F194A and cellobiohydrolase, CtCBH5A) and xylanases (endo-1,4-β-xylanase, CtGH11A, and β-xylosidase, BoGH43), all in crude form (unpurified enzyme present in the total cellular proteins) for producing high yield of total reducing sugars using choline chloride:acetic acid pretreated rice-straw (CApRS). D-optimal mixture design approach was used for statistically designing the optimal proportion of crude recombinant enzyme cocktail for hydrolysis of delignified rice straw. The developed enzyme cocktail comprising chimera, CtCBH5A, CtGH11 and BoGH43 in ratio 35.1:41.8:10.0:13.1 resulted in cellulolytic enzyme activity, 5.6 FPU/mL and xylanase activity, 102 U/mL. Enzymatic saccharification of 3% (w/v) delignified CApRS using developed enzyme cocktail at 187 FPU/gCApRS, pH 5.8 and 35 °C, yielded total reducing sugar of 498 mg/gbiomass, glucose yield (410 mg/g) and xylose yield (71.3 mg/g) resulting in 72% saccharification efficiency. Whereas, significantly low total reducing sugar yield of 80 mg/g and 218 mg/g were released from raw RS and partially pretreated RS, respectively, by the developed cocktail under the same hydrolytic conditions, thereby inferring the effectiveness of the enzyme cocktail against CApRS biomass. The developed enzyme cocktail was compared with a commercial enzyme cocktail and prospects its applicability in lignocellulosic biorefineries.

LPMO-supported saccharification of biomass: effects of continuous aeration of reaction mixtures with variable fractions of water-insoluble solids and cellulolytic enzymes

BackgroundHigh substrate concentrations and high sugar yields are important aspects of enzymatic saccharification of lignocellulosic substrates. The benefit of supporting the catalytic action of lytic polysaccharide monooxygenase (LPMO) through continuous aeration of slurries of pretreated softwood was weighed against problems associated with increasing substrate content (quantitated as WIS, water-insoluble solids, in the range 12.5–17.5%), and was compared to the beneficial effect on the saccharification reaction achieved by increasing the enzyme preparation (Cellic CTec3) loadings. Aerated reactions were compared to reactions supplied with N2 to assess the contribution of LPMO to the saccharification reactions. Analysis using 13C NMR spectroscopy, XRD, Simons’ staining, BET analysis, and SEM analysis was used to gain further insights into the effects of the cellulolytic enzymes on the substrate under different reaction conditions.ResultsAlthough glucose production after 72 h was higher at 17.5% WIS than at 12.5% WIS, glucan conversion decreased with 24% (air) and 17% (N2). Compared to reactions with N2, the average increases in glucose production for aerated reactions were 91% (12.5% WIS), 70% (15.0% WIS), and 67% (17.5% WIS). Improvements in glucan conversion through aeration were larger (55–86%) than the negative effects of increasing WIS content. For reactions with 12.5% WIS, increased enzyme dosage with 50% improved glucan conversion with 25–30% for air and N2, whereas improvements with double enzyme dosage were 30% (N2) and 39% (air). Structural analyses of the solid fractions revealed that the enzymatic reaction, particularly with aeration, created increased surface area (BET analysis), increased disorder (SEM analysis), decreased crystallinity (XRD), and increased dye adsorption based on the cellulose content (Simons' staining).ConclusionsThe gains in glucan conversion with aeration were larger than the decreases observed due to increased substrate content, resulting in higher glucan conversion when using aeration at the highest WIS value than when using N2 at the lowest WIS value. The increase in glucan conversion with double enzyme preparation dosage was smaller than the increase achieved with aeration. The results demonstrate the potential in using proper aeration to exploit the inherent capacity of LPMO in enzymatic saccharification of lignocellulosic substrates and provide detailed information about the characteristics of the substrate after interaction with cellulolytic enzymes.

The Efficacy of Fungicides Against Cercospora beticola in Field Conditions

Abstract This study is focused on the evaluation of the efficacy of conventional fungicides against Cercospora leaf spot (CLS) on sugar beet. The results showed that the best protection against CLS was achieved by treatment with kresoxim-methyl + epoxiconazole (T1) and tetraconazole (T2). The second highest fungicide efficacy was detected after treatment with (kresoxim-methyl + epoxiconazole -T1) + difenoconazole -T2, followed by (azoxystrobin + cyproconazole) + difenoconazole, (prochloraz + propiconazole) + tetraconazole, Urtica dioica plant extracts + Salix spp. plant extracts, (trifloxystrobin + cyproconazole) + tetraconazole, and picoxystrobin + tetraconazole. The positive effect of fungicide protection on yield and sugar content was higher in the year with a higher occurrence of CLS. Good CLS management could increase the root yield by up to 19.34%, and sugar yield by up to 23.83% in comparison to the untreated check. The highest sugar yield was achieved in the treatment by (prochloraz + propiconazole) + tetraconazole, followed by (kresoxim-methyl + epoxiconazole) + difenoconazole, (azoxystrobin + cyproconazole) + difenoconazole, (trifloxystrobin + cyproconazole) + tetraconazole, picoxystrobin + tetraconazole, and Urtica dioica plant extracts + Salix spp. plant extracts. The results showed a strong relationship of root yield and sugar yield on fungicide treatment during the vegetation. The occurrence of fungicide resistance in Cercospora beticola population has an important impact on efficacy of applied fungicides in field conditions. The highest economic effectiveness coefficient was achieved at treatment by (prochloraz + propiconazole) + tetraconazole.

Preparation and Catalytic Properties of Graphene Oxide/ Phosphotungstic Acid Composites

Background: Cellulose structures are in stable crystallineform. The hydrolysis of cellulose to small reducing sugars is difficult, but essential for its utilization Objective: To investigate the effect of graphene oxide (GO) loading on the catalytic performance of phosphotungstic acid (HPW) for the catalyzed hydrolysis of cellulose, with the purpose to get high yield of total reducing sugar (TRS). Methods: Graphene oxide/phosphotungstic acid (GO/HPW) composites were prepared using a liquid-phase composite method. The materials were applied to catalyze hydrolysis of microcrystalline cellulose in 1-butyl-3-methylimidazole chloride ionic liquid ([Bmim]Cl). The samples were characterized by Powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Field emission scanning electron micrographs (FE-SEM), pyridine IR and acid-base chemical titration. Results: The Brønsted acidic sites were the main source of acidity in the composites and its concentration was determined to be 0.96 mmol/g. With the use of the GO/HPW composite as catalysts for cellulose hydrolysis, TRS yield of 90.5 % was obtained. Conclusion: GO/HPW composites retained the functional groups of both materials. It was the Brønsted acidic sites in the materials that effectively promoted the cellulose hydrolysis reaction. The structures of GO/HPW with the agglomeration of HPW scattered on GO had high accessibility of acidic sites and fast mass transfer of the reducing sugars to the outside of the catalysts in time to prevent their further conversion into by-products. TRS yield of 90.5 % was obtained from the hydrolysis of cellulose catalyzed by the GO/HPW (1:1.5) composites at 115 ℃ for 4 h using catalysts to cellulose 1:1 ratio.

Sugar accumulation enhancement in sorghum stem is associated with reduced reproductive sink strength and increased phloem unloading activity.

Sweet sorghum has emerged as a promising source of bioenergy mainly due to its high biomass and high soluble sugar yield in stems. Studies have shown that loss-of-function Dry locus alleles have been selected during sweet sorghum domestication, and decapitation can further boost sugar accumulation in sweet sorghum, indicating that the potential for improving sugar yields is yet to be fully realized. To maximize sugar accumulation, it is essential to gain a better understanding of the mechanism underlying the massive accumulation of soluble sugars in sweet sorghum stems in addition to the Dry locus. We performed a transcriptomic analysis upon decapitation of near-isogenic lines for mutant (d, juicy stems, and green leaf midrib) and functional (D, dry stems and white leaf midrib) alleles at the Dry locus. Our analysis revealed that decapitation suppressed photosynthesis in leaves, but accelerated starch metabolic processes in stems. SbbHLH093 negatively correlates with sugar levels supported by genotypes (DD vs. dd), treatments (control vs. decapitation), and developmental stages post anthesis (3d vs.10d). D locus gene SbNAC074A and other programmed cell death-related genes were downregulated by decapitation, while sugar transporter-encoding gene SbSWEET1A was induced. Both SbSWEET1A and Invertase 5 were detected in phloem companion cells by RNA in situ assay. Loss of the SbbHLH093 homolog, AtbHLH093, in Arabidopsis led to a sugar accumulation increase. This study provides new insights into sugar accumulation enhancement in bioenergy crops, which can be potentially achieved by reducing reproductive sink strength and enhancing phloem unloading.

Evaluation of the quantitative and qualitative characteristics of sugar beet cultivars in different sowing times and transplanting and direct-seeding systems

To study the characteristics of sugar beet cultivars in transplanting and direct-seeding systems on three different sowing times (March 29, April 8, and April 18), a split plot experiment based on randomized complete blocks in three replications was carried out in Miandoab and Bokan regions, Northwest of Iran in 2016. The results showed that the highest nitrogen content was observed between the two test locations in the Bukan area. Results showed that the low root sodium, alkalinity, and molasses content was recorded for transplanting system. The minimum content of root sodium, nitrogen, and molasses sugar was observed in the plants sown on March 29. The Dorotea cultivar showed the highest root yield, sugar yield, and white sugar yield and the lowest root nitrogen and molasses sugar content compared to Isabella and Ekbatan. The highest white sugar content, coefficient of sugar extraction, sugar yield, root yield, and white sugar yield were recorded in the transplanting system with the sowing time of March 29; however, the highest content of root potassium and sugar content was observed in the transplanting system sown on April 18. The highest root yield was observed in the Dorotea cultivar, with a sowing time of March 29. Among the locations in the cultivar and planting system interaction treatments, the highest sugar content was found in the Bukan area's Dorotea cultivar in the transplanting system. Finally, the highest sugar yield was related to the transplanting system on March 29 in the Bukan area. It can be stated that an early sowing time (March 29), transplanting, and Dorotea variety were identified as the most appropriate treatments to improve the economic traits of sugar beet.

High-Efficient Production of Cellulosic Ethanol from Corn Fiber Based on the Suitable C5/C6 Co-Fermentation Saccharomyces cerevisiae Strain

As a potential alternative to fossil-based fuels, cellulosic ethanol has attracted much attention due to its great benefit to energy sustainability and environmental friendliness. However, at present, the industrial competitiveness of cellulosic ethanol production is still insufficient compared with fossil-based fuels because of the higher costs. Expanding the range of lignocellulosic biomass may be a promising measure to promote the economical production of cellulosic ethanol. Corn fiber, a byproduct from the corn deep-processing, is an attractive feedstock for cellulosic ethanol production because of its rich carbohydrate content (generally exceeding 65% of dry weight), almost no transportation cost, and low lignin content allow it to be easily handled. This study first optimized the hydrolysis conditions, including the pretreatment and enzymolysis process based on dilute sulfuric acid, to achieve a high sugar yield. Then, the corn fiber hydrolysates obtained under different hydrolysis conditions were suitably fermented by different C5/C6 co-fermentation Saccharomyces cerevisiae, indicating that the hydrolysate at high solid loading (20%) needs to detoxification to a certain extent but not low solid loading (10%) to achieve high ethanol yield. Finally, the fermentation of the 20% solid loading hydrolysates with resin detoxification was performed in a 50 L bioreactor, achieving the sugar (glucose and xylose) metabolic rate of 2.24 g L −1 h −1 and ethanol yield of 92% of the theoretical value, which are the highest reported levels to date. This study provided a potential process route for cellulosic ethanol production from corn fiber from the perspective of the suitability between the upstream hydrolysis process and the downstream fermentation strain.

Experimental and kinetic analyses of delignification of lignocellulosic grass with minimal holocellulose loss during pretreatment

This work aims to develop an experimental and theoretical framework for converting the holocellulose present in an agro-residue to bioethanol without separating the cellulose and the hemicellulose from each other. Three delignification methods are employed to reduce holocellulose loss, and achieve a high yield of fermentable sugars through enzymatic hydrolysis: sodium chlorite-acetic acid (SC-AA), sodium chlorite-acetone (SC-AC), and separate SC-AA. The experimental methodology and theoretical analyses suggest that the separate SC-AA method is an effective delignification technology that preserves the maximum possible holocellulose content (11.7 % loss) while simultaneously removing lignin from agro-residues. Furthermore, this process also increases the accessibility of the holocellulose pores by restricting the adsorption of delignified products in the pores of the substrate, thus increasing the pore volume available for enzymatic hydrolysis reactions. The multi-stage modeling approach predicts the reaction time for delignifying agro-residues and quantifies the impact of reaction parameters on holocellulose retention.