Reducing Sugar Production Research Articles

Pretreatment of Leucaena leucocephala wood by acidified glycerol: optimization, severity index and correlation analysis

In this study, Leucaena leucocephala wood was pretreated with aqueous glycerol having H2SO4 as the catalyst. Response surface methodology (RSM) and artificial neural network (ANN) were used to optimize the process parameters, catalyst concentration (1–3%), duration (120–300 min) and temperature (100–150 °C). ANN gave more accurate predictions for total reducing sugar yield than RSM. ANN also had lower values for error functions. Severity index (SI) was calculated based on the temperature, duration and catalyst concentration. Increase in SI from 0.21 * 103 to 2.06 * 103 increased total reducing sugar (TRS) production from 39.97 g/kg to 321.8 g/kg. Further increase in SI reduced the TRS and this change positively correlates with the loss of cellulose content. Correlation analysis showed that severity index can also be used to describe pretreatment process.

Optimisation of organosolv pretreatment for the extraction of polyphenols from spent coffee waste and subsequent recovery of fermentable sugars

In the present study, organosolv pretreatment strategy was modified for the comprehensive utilisation of spent coffee waste (SCW) for polyphenol extraction and reducing sugar production. A response surface design involving four factors viz. ethanol concentration, temperature, time and H2SO4 concentration was created for optimisation of polyphenol extraction from SCW. 11.2 mg GAE of polyphenol content/g of SCW was obtained using ethanol (68% v/v) at 51 °C for 45 min in the presence of 1.5% H2SO4 as catalyst. Furthermore, 13.78 of QE of Total Flavonoid Content/g of SCW was obtained following this process which was 7.6-fold higher than control (1.81 QE/g of SCW). Lignin removal of 24.4% was achieved following modified organosolv protocol. Enzymatic hydrolysis of pretreated SCW yielded 29.05 mg/g of total reducing sugar, which was 1.27-fold higher than control (22.8 mg/g). XRD, FTIR, and DSC profiles of the pretreated substrates were analysed for various changes incurred in pretreated SCW.

Optimization of reducing sugars production from agro-residue coconut leaflets using autoclave-assisted HCl hydrolysis with response surface methodology

The utilization of coconut leaflets, an agro residue generated from coconut farming, was investigated to develop a process to release reducing sugars using hydrochloric acid (HCl)-assisted, autoclave-based hydrolysis. The variables affecting HCl hydrolysis (duration of autoclaving, concentration of HCl and weight of coconut leaflets) were screened using a one factor at-a-time approach. The duration of autoclaving and concentration of HCl both had significant effects on the hydrolysis process and the levels of these factors were further optimized using a central composite design with response surface methodology. The optimized conditions were 3.17% of HCl and 44.14 min of autoclaving that released the maximum reducing sugars of 29 g/L. A second order model was generated, which was a good fit with a coefficient of determination value of 0.83.

Optimization of reducing sugar production from enzymatic hydrolysis of banana peels using response surface methodology

Optimization of reducing sugar production from enzymatic hydrolysis of banana peels using response surface methodology

Coordinated Regulation of Cold Induced Sweetening in Tetraploid Potato Families by Isozymes of UDP-Glucose Pyrophosphorylase and Vacuolar Acid Invertase

Past investigations have suggested that both UGPase and AcInv activities can be used as markers to screen genetically diverse potato clones for cold induced sweetening resistance (CIS-R). The goal of this study was to define their cooperative interaction in regulating sweetening. Inter- and intra-ploidy hybridizations of good (G) and poor (P) processing 24 or 48 chromosome potato clones were used to create 24 potato families. Potatoes were field grown and 460 progeny (≤20 each family) were stored for five months in the cold (4 C). Tubers from each progeny plant were evaluated for cold induced sweetening resistance (CIS-R) and correlated with the percentage of A-II isozymes of UDP-glucose pyrophosphorylase (UGPase; EC 2.7.7.9); and acid invertase activity (AcInv; EC 3.2.1.26). Each progeny was given a CIS-R score of 1–10 (1-most resistance, 10 least resistance). The families were grouped into four classes based on (1) high or low AcInv activity (low being a SA of 0.30 or less) (2) high or low percentage of A-II isozymes (low being 50% or less), and (3) CIS-R score. In high AcInv families, CIS-R was low regardless of the percentage of A-II isozymes present. In low AcInv activity families, there was a trend for average chip color to improve as the percentage of A-II isozymes increased from 0% to 40%. This increase in CIS-R in low AcInv families is likely due to the kinetic properties unique to the A-II forms of UGPase (principally UGP5) which limit the formation of sucrose via sucrose-6-phosphate synthase (SPS; EC 2.4.1.14). Lower concentrations of sucrose can lead to a decrease in reducing sugar production via vacuolar AcInv and lighter chip and fry colors. In selecting tetraploid parents, for the development of processing potato clones with improved CIS-R, it is recommended they have a basal AcInv SA of 0.30 or less and have A-II isozymes of UGPase.

การผลิตน้ำตาลรีดิวซ์จากทะลายเปล่าปาล์มด้วยเอนไซม์ Cellic Ctec2®

การผลิตน้ำตาลรีดิวซ์จากทะลายเปล่าปาล์มด้วยเอนไซม์ Cellic Ctec2®

Statistical modelling and optimization of alkaline peroxide oxidation pretreatment process on rice husk cellulosic biomass to enhance enzymatic convertibility and fermentation to ethanol

The complex and ordered arrangements of the lignocellulosic materials make them recalcitrant for their conversions to ethanol. Pretreatment is a crucial step in overcoming these hindrances. In this study, a 23-full factorial design of experiments optimization technique was applied on the alkaline peroxide oxidation pretreatments of rice husks biomass. The low–high levels of the influencing variables on pretreatments were; temperature (100–120 °C), time (1–2 h), % (v/v)H2O2 concentration (1–3%). Under the prevailing pretreatments, the optimum conditions were predicted and validated to be 109 °C, 2 h, and 1.38% H2O2 which yielded 56% (w/w) cellulose content, 55% (w/w) hemicellulose solubilization, and 48% (w/w) lignin removal. At the established optimum pretreatment conditions, and considering variations in biomass and enzymes loadings, maximum reducing sugars production was 205 mg/g dry biomass at different enzymatic hydrolysis conditions of 3% biomass loading, hydrolysis temperature of 45 °C, hydrolysis time of 24 h, and 35 FPU/g cellulose enzyme loading. The highest cellulose conversion of 33% yielded 24 g/L ethanol at the end of the first day of saccharification and fermentation. Physical, structural, and morphological investigations on raw and treated materials using tools such as stereomicroscopy, scanning electron microscopy, and fourier transform infrared spectroscopy further revealed the effectiveness of chosen method on rice husks biomass.

Combined Effects of Ionic Liquid and Tungsten–Halogen Radiation on Heterogeneous Hydrolysis Kinetics of Waste Papaya Epidermis for Production of Total Reducing Sugar

This article reports on optimization and kinetic modeling of Amberlyst-36 heterogeneous catalytic hydrolysis of papaya (Carica Papaya) epidermis (PE) in conjunction with ionic liquid (1-butyl-3-methylimidazolium chloride, [BMIM]Cl) for total reducing sugar (TRS) production. The intensification effects in presence of tungsten–halogen radiator (THR) on sequential pretreatment and hydrolysis have been optimized. In pretreatment and hydrolysis, the optimized factors were 70 and 80 °C reactor temperature, 20 and 10 min batch time, water to PE ratio (w/w) of 5 and 20 respectively. An optimum 2.5 (w/w) NH4OH loading in pretreatment while 7.5 wt% catalyst concentration and 20 (w/w) [BMIM]Cl loading in hydrolysis using the tungsten–halogen radiated reactor (THRR) yielded maximum 89.02 mol% TRS which was significantly greater than that obtained (37.41 mol%) through the conventionally heated reactor (CHR). Eley–Rideal mechanism best fitted the hydrolysis kinetics while pseudo-homogeneous model could best represent pretreatment kinetics. Remarkably, the larger activation energy (69.02 kJ/mol) in CHR in comparison with THRR evidently established the greater energy-efficiency of the THRR system. The evaluated kinetic parameters can be useful for reactor design and scale-up studies. The developed energy-efficient, green hydrolysis for optimum TRS synthesis from papaya epidermis also provides sustainable valorization of similar lignocellulosic biomass waste.

Statistical Modeling And Optimization Of Pretreatment For Fermentable Sugars Production From Cotton Gin Waste

ABSTRACTBioethanol is produced from lignocellulosic materials, such as agricultural waste, forest residues, etc. In this study, cotton gin waste was utilized to produce fermentable sugars through an effective pretreatment method. Autoclaving, steam explosion, and liquid hot water pretreatments were compared for their effectiveness in disruption of the lignocellulose matrix. Autoclaving was proved to be an effective pretreatment method in terms of maximum reducing sugar production. The Box–Behnken design (BBD) was employed in the optimization of autoclaving pretreatment. Slurry density (X1, g/mL), temperature (X2, °C), and time (X3, min) were chosen as the independent variables and the total reducing sugar concentration (Y, mg/L) as the dependent variable (response). The total reducing sugar production from cotton gin waste was found to be 511.48 mg/L experimentally, at an optimum slurry density of 0.50 g/mL, a temperature of 138°C, and a time of 11 min.

Enhanced reducing sugar production by saccharification of lignocellulosic biomass, Pennisetum species through cellulase from a newly isolated Aspergillus fumigatus

A cellulose degrading fungus Aspergillus fumigatus (CWSF-7) isolated from decomposed lignocellulosic waste containing soil was found to produce high titer of cellulases. The optimum activity of CMCase and FPase were 1.9 U/mL and 0.9 U/mL respectively while the highest protein concentration was found to be 1.2 mg/mL. Saccharification of two Pennisetum grass varieties [dennanath (DG) and hybrid napier grass (HNG)] were optimized using partially purified CMCase and FPase in equal concentration, i.e. a ratios of 1:1 and further with addition of commercial xylanase using response surface methodology (RSM). The production of total reducing sugar (TRS) using isolated cellulase were 396.6 and 355.8 (mg/g), whereas further addition of xylanase had higher TRS titers of 478.7 and 483.3 (mg/g) for DG and HNG respectively as evident from HPLC analysis. Further, characterization of the enzyme saccharified DG and HNG by SEM and ATR-FTIR revealed efficient hydrolysis of cellulose and partially hydrolysis of hemicellulose.

The effect of beta-glucosidase supplementation on enzymatic hydrolysis of cellulose in hydrothermally pretreated sugar beet shreds

Sugar beet shreds were pretreated by hydrothermal procedure to investigate the effect of beta-glucosidase supplementation at different substrate loading on the rate of cellulose hydrolysis. Cellulose in the hydrothermally pretreated substrate was more efficiently hydrolyzed by enzymes than in untreated material, resulting in more than two times higher release of reducing sugars. In the investigated range of solids load, supplementation of fungal cellulases cocktail by beta-glucosidase increased production of reducing sugars from substrates, while 0.25 U/g was sufficient to achieve the highest effect under applied conditions.

The effect of organosolv pretreatment on optimization of hydrolysis process to produce the reducing sugar

As the fossil energy decrease such as petroleum and natural gas, that are encourages a lot of research to develop new sources of energy from renewable raw materials. One of the source is through reducing sugar (glucose and xylose) obtained from coffee pulp waste; this is due to abundant production of coffee pulp every year reaching 743 kg/ha. In addition, this waste has not been used optimally and the cellulose and hemicellulose content of the coffee is high. The purpose of this study is to get the optimal operating condition for reducing sugar production from coffee pulp waste. The method used for optimization is Response Surface Methodology with Central Composite Design. The optimum operation condition obtained was pH 4.63 at 34ºC for 16.29 hours of hydrolysis. As a result, the predicted yield gained was 0.147 grams of reducing sugars / gram of cellulose+hemicellulose. The result indicates the gained yield was 0.137 grams of reducing sugars / gram of cellulose+hemicellulose.

Combination of hydrothermal pretreatment and sodium hydroxide post-treatment applied on wheat straw for enhancing its enzymatic hydrolysis

Wheat straw was respectively pretreated by water, dilute sulfuric acid, and sodium hydroxide solution at elevated temperature. Among the pretreatments, hydrothermal process was carried out with different severities. Hydrothermal pretreated sample and dilute acid pretreated sample were subsequently extracted by sodium hydroxide solution at room temperature which was applied as post-treatment. The pretreated samples were then enzymatically hydrolyzed to evaluate reducing sugar recovery. The result indicated that alkaline pretreatment removed a significant amount of lignin. While hydrothermal pretreatment and dilute acid pretreatment solubilized a significant amount of hemicellulose. And the hydrothermal pretreatment severity affected the solubilization of hemicellulose. The alkaline pretreated sample achieved the highest reducing sugar recovery e.g. 38.5 g sugar/100 g wheat straw. The alkaline post-treatment enhanced the enzymatic hydrolysis of acidic pretreated samples by removing additional hemicellulose and lignin. The best reducing sugar recovery was obtained at 43.6 g sugar/100 g wheat straw which indicated that the combination of hydrothermal pretreatment and alkaline extraction is a promising method in terms of reducing sugar production.

Enhancing bioethanol production from water hyacinth by new combined pretreatment methods

This study investigated the possibility of enhancing bioethanol production by combined pretreatment methods for water hyacinth. Three different kinds of pretreatment methods, including microbial pretreatment, microbial combined dilute acid pretreatment, and microbial combined dilute alkaline pretreatment, were investigated for water hyacinth degradation. The results showed that microbial combined dilute acid pretreatment is the most effective method, resulting in the highest cellulose content (39.4 ± 2.8%) and reducing sugars production (430.66 mg·g−1). Scanning Electron Microscopy and Fourier Transform Infrared Spectrometer analysis indicated that the basic tissue of water hyacinth was significantly destroyed. Compared to the other previously reported pretreatment methods for water hyacinth, which did not append additional cellulase and microbes for hydrolysis process, the microbial combined dilute acid pretreatment of our research could achieve the highest reducing sugars. Moreover, the production of bioethanol could achieve 1.40 g·L−1 after fermentation, which could provide an extremely promising way for utilization of water hyacinth.

Bacillus subtilis with endocellulase and exocellulase activities isolated in the thermophilic phase from composting with coffee residues

The goal of this study was to isolate, select and characterize bacteria with cellulolytic activity from two different coffee residue composting piles, one of which had an internal temperature of 57°C and pH 5.5 and the other, a temperature of 61°C, and pH 9.3. Culture media were manipulated with carboxymethylcellulose and crystalline cellulose as sole carbon sources. The enzyme activity was assessed by hydrolysis halo formation, reducing sugar production and zymograms. Three out of twenty isolated strains showed higher enzymatic activity and were identified as Bacillus subtilis according to their morphological, physiological, biochemical characteristics and based on the sequence analysis of 16S rDNA regions. The enzymatic extracts of the three selected strains showed exocellulase and endocellulase maximum activity of 0.254 and 0.519 U/ml, respectively; the activity of these enzymes was maintained even in acid pH (4.8) and basic (9.3) and at temperatures of up to 60°C. The enzymatic activities observed in this study are within the highest reported for cellulose produced by bacteria of the genus Bacillus. Endocellulase activity was shown in the zymograms from 24h until 144h of incubation. Furthermore, the pH effect on the endocellulase activity is reported for the first time by zymograms. The findings in this study entail the possibility to use these enzymes in the procurement of fermentable substrates for the production of energy from the large amount of residues generated by the coffee agroindustry.

The effect of a lytic polysaccharide monooxygenase and a xylanase from Gloeophyllum trabeum on the enzymatic hydrolysis of lignocellulosic residues using a commercial cellulase.

Hydrolysis of lignocellulosic biomass depends on the concerted actions of cellulases and accessory proteins. In this work we examined the combined action of two auxiliary proteins from the brown rot fungus Gloeophyllum trabeum: a family AA9 lytic polysaccharide monooxygenase (GtLPMO) and a GH10 xylanase (GtXyn10A). The enzymes were produced in the heterologous host Pichia pastoris. In the presence of an electron source, GtLPMO increased the activity of a commercial cellulase on filter paper, and the xylanase activity of GtXyn10A on beechwood xylan. Mixtures of GtLPMO, GtXyn10A and Celluclast 1.5L were used for hydrolysis of pretreated wheat straw. Results showed that a mixture of 60% Celluclast 1.5L, 20% GtXyn10A and 20% GtLPMO increased total reducing sugar production by 54%, while the conversions of glucan to glucose and xylan to xylose were increased by 40 and 57%, respectively. This suggests that GtLPMO can contribute to lignocellulose hydrolysis, not only by oxidative activity on glycosidic bonds, but also to hemicellulose through the oxidation of xylosyl bonds in xylan. The concerted action of these auxiliary enzymes may significantly improve large-scale recovery of sugars from lignocellulose.

Thermo-carbide slag pretreatment of turfgrass pruning: Physical-chemical structure changes, reducing sugar production, and enzymatic hydrolysis kinetics

Alkaline pretreatment shows a good effect on delignification of lignocellulosic biomass, and carbide slag, an alkaline industrial waste, was first applied to pretreat turfgrass pruning. Three thermo-alkaline pretreatment methods were compared to evaluate their ability to destroy the biomass structure and to enhance the enzymatic hydrolysis efficiency of turfgrass pruning, namely thermo-NaOH pretreatment, thermo-lime pretreatment, and thermo-carbide slag pretreatment. Results showed that the maximum net reducing sugar yield of 269.55 mg/g raw biomass was achieved by thermo-carbide slag pretreatment. Compared with raw biomass, the lignin and hemicellulose content of turfgrass pruning after thermo-carbide slag pretreatment reduced by 35.57% and 62.40%, respectively. SEM and FTIR analyses showed that the surface structure and chemical groups of turfgrass pruning were obviously destroyed by thermo-carbide slag pretreatment. There was a high positive correlation between the enzymatic hydrolysis efficiency and cellulose content of substrate. However, a high negative correlation was observed between the enzymatic hydrolysis efficiency and lignin content of substrate. The enzymatic hydrolysis kinetics with different pretreatments were well described by the fractal-like kinetics model, and the rate constant of enzymatic hydrolysis of thermo-alkali pretreated turfgrass pruning was about three times of that of the unpretreated turfgrass pruning. Overall, carbide slag is an ideal pretreatment material for enzymatic hydrolysis of turfgrass pruning in terms of hydrolysis efficiency and waste reuse.

Enhancement of Enzymatic Hydrolysis of Lignocellulosic Materials by Nonionic Surfactant

Palm fruit bunch (PFB) and palm fruit residue (PFR) are considered as potential raw materials for ethanol production due to their large availability from palm oil industry. However, the presence of lignin can retard the rate of enzymatic hydrolysis. Both PFB and PFR were pretreated with a 10% w/v sodium hydroxide solution. The amounts of their hemicellulose were substantially decreased whereas their lignin contents were slightly reduced. After that, they were hydrolyzed using cellulase from Trichoderma reesei (ATCC 26921) at 50 °C and pH 5. An addition of Tween 80, nonionic surfactant, with 0.25% w/v concentration provided an increase in reducing sugar production about 50.5% at 10 FPU/g PFB cellulase loading, while the addition of Tween 80 with 0.5% w/v concentration increased reducing sugar production by 38.8% at 20 FPU/g PFR cellulase loading. The greater the amount of lignin in the lignocellulosic materials, the higher the dosages of enzyme and surfactant required for the enzymatic hydrolysis. The adsorption of added nonionic surfactant onto the hydrophobic surface of lignin resulted in an increase in the availability of added enzyme to both cellulose and hemicellulose, leading to the enhancement of enzymatic hydrolysis. Additionally, the adsorption of cellulase on PFB and PFR were well fitted with the Freundlich isotherm.

Activity of chitosan-lysozyme nanoparticles on the growth, membrane integrity, and β-1,3-glucanase production by Aspergillus parasiticus.

Synthesis of nanocomposites from antimicrobial biopolymers such as chitosan (CS) and lysozyme (LZ) is an important and promising area in bionanotechnology. Chitosan-lysozyme (CS-LZ) nanoparticles (NPs) were prepared by the nanoprecipitation method, using commercial chitosan of 153kDa. TEM and dynamic light scattering (DLS) analysis were carried out to evaluate the morphology, size, dispersion, and Z potential. Association efficiency of lysozyme was determined using Coomassie blue assay. The antifungal activity of NPs against Aspergillus parasiticus was evaluated through cell viability (XTT), germination and morphometry of spores, and reducing sugars production; the effects on membrane integrity and cell wall were also analyzed. NPs' size were found in the range of 13.4 and 11.8nm for CS-LZ and CS NPs, respectively, and high Z potential value was observed in both NPs. Also, high association of lysozyme was presented in the CS matrix. With respect to the biological responses, CS-LZ NPs reduced the viability of A. parasiticus and a strong inhibitory effect on the germination of spores (100% of inhibition) was observed at 24h in in vitro assays. CS-LZ and CS NPs affected the membrane integrity and the cell wall of spores of fungi with respect to control, which is consistent with the low amount of reducing sugars detected. CS-LZ NPs prepared by nanoprecipitation promise to be a viable and safe alternative for use in biological systems, with a possible low or null impact to humans and biota. However, the potential benefits and the environmental and health implications of NPs need to be globally discussed due to its possible negative effects.

Structural and Functional Characterization of TwoPennisetumsp. Biomass during Ultrasono-Assisted Alkali Pretreatment and Enzymatic Hydrolysis for Understanding the Mechanism of Targeted Delignification and Enhanced Saccharification

The recalcitrance offered by lignocellulose to get converted into simple sugars makes its conversion process complicated, hence pretreatment is required prior to enzymatic hydrolysis and fermentation. Ultrasonication-assisted alkali pretreatment (UA-NaOH) was found to be an effective pretreatment for delignification and enzymatic hydrolysis of denanath grass (DG) and hybrid napier grasses (HNG) in terms of maximum delignification and reducing sugar production. To determine the mechanism of pretreatment and enzymatic hydrolysis, the structural and functional characterization of native and pretreated grass biomass were investigated using SEM (scanning electron microscope), FT-IR (Fourier transformation infrared) spectroscopy, TGA (thermal gravimetric analysis), DSC (differential scanning) spectroscopy, and solid state 13C CP/MAS NMR (cross-polarization magic angle spinning nuclear magnetic resonance) spectroscopy. The surface erosions, distorted surface morphology and deconstruction of the cell wall compone...