Improve Sugar Recovery Research Articles

Improved Sugar Recovery from Mandarin Peel under Optimal Enzymatic Hydrolysis Conditions and Application to Bioethanol Production

Improved Sugar Recovery from Mandarin Peel under Optimal Enzymatic Hydrolysis Conditions and Application to Bioethanol Production

A novel autoclave-assisted nanoparticle pre-treatment for improved sugar recovery from potato peel waste: process optimisation, nanoparticle recyclability and bioethanol production

A novel autoclave-assisted nanoparticle pre-treatment for improved sugar recovery from potato peel waste: process optimisation, nanoparticle recyclability and bioethanol production

Improved Sugar Recovery of Alkaline Pre-Treated Pineapple Leaf Fibres via Enzymatic Hydrolysis and Its Enzymatic Kinetics

The biofibre complex structure in pineapple leaf fibres (PALFs) can be disrupted using the alkaline pre-treatment method with sodium hydroxide (NaOH). Nonetheless, the pre-treated structures have an impact on the bioconversion of PALFs into sugar. Thus, the impact necessitates precise reaction conditions, which are required for the enzymatic hydrolysis of PALFs. In this study, the Box–Behnken design (BBD) was utilised to achieve maximum sugar yield from PALFs. The optimised enzymatic hydrolysis conditions were 229 µg/mL of cellulase, a reaction temperature of 45 °C, and a hydrolysis time of 69 h. Resultantly, an 84% increase in sugar yield was observed, from 17.26 mg/mL to 108.74 mg/mL after the optimisation process. Moreover, a significant influence (p = 0.0009) of the enzymatic hydrolysis on hydrolysis time and temperature was observed. Additionally, the kinetic study analysis of NaOH pre-treatment and the enzymatic hydrolysis process were investigated. The kinetics of enzyme concentrations on total reducing sugar (TRS) production using an insoluble substrate were investigated based on modified Michaelis–Menten and Chrastil models. The result of the models is in good agreement with the experimental data, as the PALF hydrolysis process was reasonably well predicted. This study provides valuable information for predicting the sugar yield of the PALF bioconversion.

Modified sugar beet pulp and cellulose-based adsorbents as molasses quality enhancers: Assessing the treatment conditions

To tackle the issue of non-sugar compounds reduction in sugar beet molasses towards improved sugar recovery and complete molasses valorisation, various treatments were developed. As a step forward to sustainability, this study explores the applicability of alkaline hydrogen peroxide treated sugar beet pulp (AHPSBP) and commercial cellulose-based adsorbents for molasses purification by monitoring the changes in molasses colour, turbidity and sucrose content. Treatment conditions defined by Box-Behnken design were pH (3–7), molasses dry substance (30–50° Brix), and adsorbent concentration (9–21 g/L) with constant treatment temperature. Favourable conditions for molasses colour reduction were acidic and neutral environment for commercial adsorbents (4.9–27.1%) and AHPSBP (20.3–32.7%), respectively. Turbidity reduction was higher than 90% in neutral environment regardless of applied adsorbent with minimal detected sucrose content reduction. AHPSBP exhibited greater potential regarding molasses colour and turbidity reduction compared to commercial adsorbents obtained at favourable pH with lower applied concentrations.Accordingly, AHPSBP was introduced as a novel, abundant, and low-cost adsorbent for molasses quality enhancement, contributing to the existing results concerning molasses purification obtained by bentonite and activated carbon application.

A green and efficient way to improve sugar recovery of wheat straw by ultrasonic-assisted xylanase pretreatment

A green and efficient way to improve sugar recovery of wheat straw by ultrasonic-assisted xylanase pretreatment

Improved sugar recovery from enzymatic hydrolysis of Miscanthus sinensis by surfactant-mediated alkaline pretreatment

Surfactants play a vital role in the removal of lignin and subsequent enzymatic saccharification of lignocellulosic biomass. In this work, a surfactant-mediated alkaline pretreatment (SMAP) with short residence time and low NaOH loading has been successfully developed for enhancing enzymatic hydrolysis of a potential energy plant, Miscanthus sinensis, and evaluating its potential as a feedstock for biofuel production. As compared to individual alkaline pretreatment (AP), the SMAP process resulted in significantly more hemicellulose removal, more efficient delignification, higher cellulose content (55% vs. 51%), and stronger morphological disruption of the pretreated stalks, making them more accessible to cellulases and/or microorganisms. As a result, SMAP produced a significantly higher sugar yield of 402.5 mg/g than the control and AP group (287.8 mg/g) (p < 0.05). Among the tested surfactants, Tween 40 was identified as a potential candidate for SMAP of biomass wastes. SMAP with mild conditions (i.e., 121 °C, 10 min, 1.0% NaOH, 1.0% Tween 40) gave the highest sugar yield of 566.0 mg/g, which were 6.5-folds greater than the raw stalk. These demonstrations for using SMAP to achieve enhanced lignin removal and sugar recovery from biomass highlight its strong application potentials of improving bioconversion of lignocellulosic biomass like Miscanthus sinensis, hence making this crop a valuable energy plant.

Improved Sugar Recovery from Orange Peel by Statistical Optimization of Thermo-Alkaline Pretreatment

Orange peel, which is a by-product of oranges, contains carbohydrates that can be converted into sugars and used in the fermentation process. In this study, the thermal alkaline pretreatment process was chosen because of its simplicity and lesser reaction time. In addition, the reaction factors were optimized using response surface methodology. The determined optimal conditions were as follows: 60.1 g/L orange peels loading, 3% KOH and 30 min. Under the optimal conditions, glucan content (GC) and enzymatic digestibility (ED) were found to be 32.8% and 87.8%, respectively. Enzymatic hydrolysis was performed with pretreated and non-pretreated orange peels using three types of enzyme complex (cellulase, cellobiase and xylanase). The minimum concentrations of enzyme complex required to obtain maximum ED were 30 FPU (filter paper unit), 15 CBU (cellobiase unit), and 30 XNU (xylanase unit) based on 1 g-biomass. Additionally, ED of the treated group was approximately 3.7-fold higher than that of the control group. In conclusion, the use of orange peel as a feedstock for biorefinery can be a strategic solution to reduce wastage of resources and produce sustainable bioproducts.

Batch and fed-batch enzymatic hydrolysis of pretreated sugarcane bagasse – Assays and modeling

Choosing the right pretreatment for a specific biomass in order to improve sugar recovery is a key step towards the commercial feasibility of cellulosic ethanol. This article deals with the enzymatic hydrolysis of sugarcane bagasse subjected to either delignification or hydrothermal pretreatment. Two operational strategies were studied: batch experiments were carried out with different solids loads (5–20% w/v) and fed-batch tests reached cumulative solids content of 24% (w/v). The highest glucose concentration (127 g/L) was achieved when working with the delignified material in fed-batch systems. However, the reactions using delignified bagasse presented sharp decrease in conversion when the solids loads exceeded 15% (w/v). During the modeling phase, the hydrolysis behavior was described according to a semi-mechanistic approach. The goodness of fit evaluation showed that the models performed well when compared to the collected data. Finally, fed-batch simulations suggested new feeding polices to increase the final glucose content.

Study on Mass Transfer Kinetics of Sugar Extraction from Sweet Sorghum Biomass via Diffusion Process and Ethanol Yield Using SSF

Sweet sorghum juice, a potential bioethanol feedstock, can be incorporated into the dry-grind ethanol process to improve sugar utilization efficiency, thereby enhancing ethanol yields. The juice is normally obtained by pressing the stalk through roller mills in tandem. Juice extraction by this process is known to be labor intensive, less efficient, and susceptible to considerable fermentable sugar loss due to microbial activities when stored at room temperature. Sweet sorghum juice extraction via diffusion has recently been proposed to improve sugar recovery efficiency. In this study, extraction kinetics based on the optimized diffusion parameters (8% grain loading, 85 °C, and 120 min) were determined to describe the mass transfer of sugars in sweet sorghum biomass during the diffusion process. Diffusion parameters obtained from previous studies were used to extract free sugars and convert them into ethanol using granular starch hydrolyzing enzymes (GSHE) and traditional enzymes. Ethanol yields at 72 h of fermentation mashes treated with GSHE and those with traditional enzymes were comparable (14.49–14.56%, v/v). Ethanol fermentation efficiencies also ranged from 88.92–92.02%.

The impact of particle size of cellulosic residue and solid loadings on enzymatic hydrolysis with a mass balance

Rice straw has a great potential for ethanol production due to its richness in polysaccharides and abundant availability, however, for efficient utilization of these polysaccharides, size reduction is a prerequisite step. Therefore, biomass particle size plays a vital role for cellulosic ethanol commercialization. In this study, the effects of rice straw particle size on dilute acid pretreatment efficiency and enzymatic hydrolysis are investigated. Different sizes; 5, 10 and 20 mm were subjected to dilute acid pretreatment in a continuous pilot scale system with a horizontal screw feeder reactor followed by enzymatic hydrolysis at varying solids (10 and 15%) and enzyme dosages (5 and 10 FPU/g of pretreated residue). The glucan hydrolysis for 5, 10 and 20 mm are 65.6, 80.0 and 60.0% using 5 FPU and 79.5, 93.4 and 72.8% using 10 FPU/g pretreated residue respectively at 10% loading, whereas, at 15% it is significantly lower in respective experiment. Overall sugar recovery with 10 mm is 63.8 and 72.9% with 5 and 10 FPU respectively. RS with 10 mm biomass particle size at both solid loadings and enzyme dosages resulted in much higher enzymatic hydrolysis than others and in turn the overall sugar recovery and this was found to be due to the variation in the degradation products and pseudolignin contents in the pretreated biomass. The insight into the structural intricacies of biomass after pretreatment are studied using FT-IR and SEM revealing significant changes in biomass properties responsible for improved sugar recovery.

RETRACTED: Enhancing delignification and subsequent enzymatic hydrolysis of corn stover by magnesium oxide-ethanol pretreatment

Corn stover pretreatment by MgO-ethanol was investigated to improve sugar recovery by reducing sugar degradation and enhance enzymatic hydrolysis by improving delignification and reducing inhibitor formation. Results showed MgO as an effective additive and Lewis base, functioned to neutralize the acids released from hemicellulose during pretreatment, reduce monosaccharide degradation and inhibitor formation, and enhance delignification. The optimal pretreatment conditions were 50% ethanol, 0.08 mol/L MgO, and 10% solid loading at 190 °C for 40 min. Under optimal conditions, 98% glucose and 92% xylose were recovered with 89% glucan and 71% xylan recoveries and 60% lignin removal. A total sugar yield of 63% on a received biomass basis after enzymatic hydrolysis was obtained with 78% glucose and 41% xylose yields. The resulting biomass slurry was near-neutral and free of furfural and 5-hydroxymethylfurfural. Thus, the process to isolate high-purity value-added lignin and recover sugars from biomass liquor can be largely simplified.

Combined dilute hydrochloric acid and alkaline wet oxidation pretreatment to improve sugar recovery of corn stover

Two-stage dilute hydrochloric acid (DA)/aqueous ammonia wet oxidation (AWO) pretreatment was used to recover the sugars of corn stover. The morphology characterizations of samples were detected by SEM, BET and SXT. The results showed that DA-AWO process demonstrated a positive effect on sugar recovery compared to AWO-DA. 82.8% of xylan was recovered in the first stage of DA-AWO process at 120 °C for 40 min with 1 wt% HCl. The second stage was performed under relative mild reaction conditions (130 °C, 12.6 wt% ammonium hydroxide, 3.0 MPa O2, 40 min), and 86.1% lignin could be removed. 71.5% of glucan was achieved with a low enzyme dosage (3 FPU·g−1) in the following enzymatic hydrolysis. DA-AWO pretreatment was effective due to its sufficient hydrolysis of hemicellulose in the first stage and remarkably removal of the lignin in the second stage, resulting in high sugar recovery with a low enzyme dosage.

Microwave-assisted alkalic salt pretreatment of corn cob wastes: Process optimization for improved sugar recovery

The present study developed three different microwave-assisted alkalic salt pretreatments (Na3PO4·12H2O, Na2CO3 and CH3COONa) to improve sugar yield from corn cob wastes. Process inputs included pretreatment time, alkalic salt concentration and microwave power intensity with the sugar yield as the corresponding output. All three pretreatment models gave high coefficient of determination values (R2> 0.85). The Na3PO4·12H2O treatment (11.55% Na3PO4.12H2O at 700 W for 6 min) led to the maximum sugar yield (0.76 ± 0.01 g/g). All three pretreatment methods displayed key structural changes in the corn cob structure after pretreatment. This study gave an 11% higher sugar yield in contrast to a previous microwave-assisted pretreatment report on corn cobs. The developed pretreatment strategy was effective for improving the sugar recovery from lignocellulosic wastes and can be channelled towards microbial production of fuels and high value commodities.

Enhancement of sugar recovery and ethanol production from wheat straw through alkaline pre-extraction followed by steam pretreatment

To improve sugar recovery and ethanol production from wheat straw, a sequential two-stage pretreatment process combining alkaline pre-extraction and acid catalyzed steam treatment was investigated. The results showed that alkaline pre-extraction using 8% (w/w) sodium hydroxide at 80 °C for 90 min followed by steam pretreatment with 3% (w/w) sulfur dioxide at 151 °C for 16 min was sufficient to prepare a substrate that could be efficiently hydrolyzed at high solid loadings. Moreover, alkaline pre-extraction reduced the process severity of steam pretreatment and decreased the generation of inhibitory compounds. During enzymatic hydrolysis, increasing solid loading decreased the yield of monomeric sugars. Enzymatic hydrolysis at 25% (w/v) solid loading, the yields of approximately 80% of glucose and 65% of xylose could be reached with an enzyme dosage of 25 mg protein/g glucan. Following fermentation of hydrolysate with sugar concentration of approximately 120 g/L, an ethanol concentration of 54.5 g/L was achieved.

Sugar beet molasses purification by bentonite addition: Analysis of quality enhancement and treatment conditions

Reduction of non-sugar compounds in sugar beet molasses through various treatments is a promising method for molasses quality enhancement, improved sugar recovery and prevention of possible changes during storage. The presented study was conducted in order to examine the effect of sodium and calcium bentonite treatment on sugar beet molasses colour, turbidity and unavoidable sucrose content reduction during the purification process. Box-Behnken experimental design was employed with 3 independent parameters: pH (3–7), molasses dry substance (30–50° Brix) and bentonite suspension concentration (9–21 g/L) while treatment temperature was constant (60 °C) in all conducted experiments. Lower pH values and increasing bentonite concentrations expressed positive influence on molasses colour and turbidity reduction. Corresponding parameters also had slightly negative impact on molasses sucrose content. Compared to the calcium bentonite, sodium bentonite exhibited better results in terms of molasses colour and turbidity reduction. Optimal treatment parameters for achieving a 29–39% reduction in colour and 91–98% in turbidity with minimal sucrose content reduction (5%) were: pH 5.11–5.17, molasses dry substance 38.5–40.3° Brix and bentonite concentration 16–21 g/L.

A two-stage pretreatment using acidic dioxane followed by dilute hydrochloric acid on sugar production from corn stover

A two-stage pretreatment method was developed to improve sugar recovery in this study.

A two-stage pretreatment process using dilute hydrochloric acid followed by Fenton oxidation to improve sugar recovery from corn stover

A two-stage pretreatment process is proposed in this research in order to improve sugar recovery from corn stover. In the proposed process, corn stover is hydrolyzed by dilute hydrochloric acid to recover xylose, which is followed by a Fenton reagent oxidation to remove lignin. 0.7wt% dilute hydrochloric acid is applied in the first stage pretreatment at 120°C for 40min, resulting in 81.0% xylose removal. Fenton reagent oxidation (1g/L FeSO4·7H2O and 30g/L H2O2) is performed at room temperature (about 20°C) for 12 has a second stage which resulted in 32.9% lignin removal. The glucose yield in the subsequent enzymatic hydrolysis was 71.3% with a very low cellulase dosage (3FPU/g). This two-stage pretreatment is effective due to the hydrolysis of hemicelluloses in the first stage and the removal of lignin in the second stage, resulting in a very high sugar recovery with a low enzyme loading.

Synergistic effects of mixing hybrid poplar and wheat straw biomass for bioconversion processes.

BackgroundLow cost of raw materials and good process yields are necessary for future lignocellulosic biomass biorefineries to be sustainable and profitable. A low cost feedstock will be diverse, changing as a function of seasonality and price and will most likely be available from multiple sources to the biorefinery. The efficacy of the bioconversion process using mixed biomass, however, has not been thoroughly investigated. Considering the seasonal availability of wheat straw and the year round availability of hybrid poplar in the Pacific Northwest, this study aims to determine the impact of mixing wheat straw and hybrid poplar biomass on the overall sugar production via steam pretreatment and enzymatic saccharification.ResultsSteam pretreatment proved to be effective for processing different mixtures of hybrid poplar and wheat straw. Following SO2-catalyzed steam explosion pretreatment, on average 22 % more sugar monomers were recovered using mixed feedstock than either single biomass. Improved sugar recovery with mixtures of poplar and wheat straw continued through enzymatic hydrolysis. After steam pretreatment and saccharification, the mixtures showed 20 % higher sugar yields than that produced from hybrid poplar and wheat straw alone.ConclusionsBlending hybrid poplar and wheat straw resulted in more monomeric sugar recovery and less sugar degradation. This synergistic effect is attributable to interaction of hybrid poplar’s high acetic acid content and the presence of ash supplied by wheat straw. As a consequence on average 20 % more sugar was yielded by using the different biomass mixtures. Combining hybrid poplar and wheat straw enables sourcing of the lowest cost biomass, reduces seasonal dependency, and results in increasing biofuels and chemicals productivity in a cellulosic biorefinery.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-015-0414-9) contains supplementary material, which is available to authorized users.

Techno-Economic Analysis of the Optimum Softwood Lignin Content for the Production of Bioethanol in a Repurposed Kraft Mill

Kraft pulping is one possible pretreatment for softwood to economically produce bioethanol. This work evaluates the techno-economic potential of using the kraft process for producing bioethanol from softwoods in a repurposed or co-located kraft mill. Pretreated loblolly pine was enzymatically hydrolyzed at low enzyme dosages of 5 and 10 FPU/g of substrate. Pretreated residue with 13% lignin content had the highest sugar recovery, 32.7% and 47.7% at 5 and 10 FPU/g, respectively. The pretreated residues were oxygen delignified and refined. In all cases, oxygen delignification improved sugar recovery, while refining was mostly effective for pulps with high lignin content. At 5 FPU/g, the sugar recovery for all kraft pulps was 51 to 53% with oxygen delignification and refining. Increasing the enzyme dosage to 10 FPU/g increased the sugar recovery for these pulps to greater than 60%. Economic analysis for the pulps with different initial lignin content showed that kraft pulps with an initial lignin content of 6.7% with oxygen delignification had an ethanol yield of 285 L/ODt wood and the lowest total production cost of $0.55/L. Pulps with initial lignin content of 18.6% had a total production cost of $0.64/L with an ethanol yield of 264 L/ODt wood.

Acid-catalyzed autohydrolysis of wheat straw to improve sugar recovery

A comparison study of autohydrolysis and acid-catalyzed autohydrolysis of wheat straw was performed to understand the impact of acid addition on overall sugar recovery. Autohydrolysis combined with refining is capable of achieving sugar recoveries in the mid 70s. If the addition of a small amount of acid is capable of increasing the sugar recovery even higher it may be economically attractive. Acetic, sulfuric, hydrochloric and sulfurous acids were selected for acid-catalyzed autohydrolysis pretreatments. Autohydrolysis with no acid at 190°C showed the highest total sugar in the prehydrolyzate. Enzymatic hydrolysis was performed for all the post-treated solids with and without refining at enzyme loadings of 4 and 10FPU/g for 96h. Acid-catalyzed autohydrolysis at 190°C with sulfurous acid showed the highest total sugar recovery of 81.2% at 4FPU/g enzyme charge compared with 64.3% at 190°C autohydrolysis without acid.