Steam Explosion Pretreatment Research Articles

In Vitro Assessment of the Prebiotic Potential of Xylooligosaccharides from Barley Straw.

Barley straw was subjected to hydrothermal pretreatment (steam explosion) processing to evaluate its potential as a raw material to produce xylooligosaccharides (XOS) suitable for use as a prebiotic. The steam explosion pretreatment generated a liquid fraction containing solubilised hemicellulose. This fraction was purified using gel permeation chromatography to obtain a fraction rich in XOS DP2-DP6. The sample was characterised through analytical techniques such as HPAEC-PAD, FTIR and MALDI-TOF-MS. The prebiotic activity was evaluated using in vitro fermentation in human faecal cultures through the quantification of short-chain fatty acid (SCFA) and lactate production, the evolution of the pH and the consumption of carbon sources. The total SCFA production at the end of fermentation (30 h) was 90.1 mM. Positive significant differences between the amount of XOS from barley straw and fructooligosaccharides after incubation were observed.

Scale-up of hydrothermal processing: Liquid hot water and pilot-scale tubular steam explosion batch reactor for bioethanol production using macroalgae Sargassum spp biomass

Sargassum spp. is a biomass that can potentially use as an alternative for bioethanol production. Hydrothermal processes (liquid hot water and steam explosion pretreatment) were carried out at different operational conditions. Enzymatic hydrolysis performed a preliminary test with different ratios 1:1 and 1:2 (cellulases and hemicellulases) of enzyme loading, once selected 1:2 ratio was obtained conversion yield of 99.91% and therefore carried a scale-up in stirred bioreactor getting 95.92% saccharification yield. Pre-simultaneous saccharification and fermentation strategy was performed in a continuous stirred tank bioreactor (CSTBR), producing ethanol yield of 57.69%, and for simultaneous saccharification and fermentation strategy was performed in a bubble column reactor was 71.37% ethanol yield. The energy efficiency was analyzed in different scenarios; the best data was 30.19 (gsugar/MJ) in the bioreactor enzymatic hydrolysis process. This development allows for establishing the conditions for a third-generation biorefinery on a circular bioeconomy using Sargassum biomass.

Extraction of Pectin from Passion Fruit Peel: Composition, Structural Characterization and Emulsion Stability.

Extraction methods directly affect pectin extraction yield and physicochemical and structural characteristics. The effects of acid extraction (AE), ultrasonic-assisted acid extraction (UA), steam explosion pretreatment combined with acid extraction (SEA) and ultrasonic-assisted SEA (USEA) on the yield, structure, and properties of passion fruit pectin were studied. The pectin yield of UA was 6.5%, equivalent to that of AE at 60 min (5.3%), but the emulsion stability of UA pectin was poor. The pectin obtained by USEA improved emulsion stability. Compared with UA, it had higher protein content (0.62%), rhamnogalacturonan I (18.44%) and lower molecular weight (0.72 × 105 Da). In addition, SEA and USEA had high pectin extraction yields (9.9% and 10.7%) and the pectin obtained from them had lower degrees of esterification (59.3% and 68.5%), but poor thermal stability. The results showed that ultrasonic-assisted steam explosion pretreatment combined with acid extraction is a high-efficiency and high-yield method. This method obtains pectin with good emulsifying stability from passion fruit peel.

Impacts of steam explosion pretreatment on semi-continuous anaerobic digestion of lignin-rich submerged macrophyte

This study evaluated the impacts of steam explosion pretreatment of lignin-rich macrophyte (Potamogeton maackianus) on semi-continuous anaerobic digestion. The pretreatment accelerated hydrolysis efficiency from 9% to 19% (untreated) to 38%–48% (pretreated), which considerably enhanced the methane yield from 108 ± 31 to 200 ± 36 mL g-VS−1. As a negative impact, the soluble COD concentration in the effluent in the pretreatment condition was high (10,000–12,000 mg L−1) due to the accumulation of steam explosion by-products (soluble lignin and phenolic compounds). This high concentration of by-products in the digestate can destabilise subsequent biological treatment processes; therefore, their removal from the digestate will be necessary. Although the concentration of inhibitory phenolic compounds in the pretreated P. maackianus was high, it was continuously removed (38 ± 10%) in the reactor, which ensured process stability. As a result, this study demonstrated for the first time the effectiveness of direct anaerobic digestion treatment of steam-exploded lignocellulose biomass over a long-term continuous operation. By summarising the results of previous studies and our study, we found that the improvement in CH4 production (y, %) by steam explosion pretreatment is regulated by lignin content in the untreated biomass (x, %-TS) and expressed by the equation, y = 18.1 e0.071x (p = 0.0001). This empirical formula indicates that the effectiveness of steam explosion pretreatment increases exponentially with an increase in the lignin content.

The structural and functional properties of dietary fibre extracts obtained from highland barley bran through different steam explosion-assisted treatments

The effects of steam explosion (SE)-assisted ultrasound (SEU), citric acid (SEC), sodium hydroxide (SEA), and cellulase (SEE) treatment on the properties of soluble dietary fibre (SDFP) extracted from highland barley bran were analysed. The results showed that SE pretreatment combined with other methods effectively improves the SDFP yield. The highest yield of SDF (20.01%) was obtained through SEA treatment. SEU-SDFP had a loose and porous structure, whereas the surface of SEC-SDFP and SEA-SDFP presented a complicated and dense texture. Although SE pretreatment reduced the thermal stability of SDFP, SEC and SEE treatment maintained its thermal stability. Furthermore, SEU-SDFP exhibited the highest water and oil holding capacities, and cholesterol and nitrite ion adsorption capacities. SEE-SDFP exhibited the best DPPH and ABTS radical scavenging abilities. In summary, four SE-assisted extraction methods had different advantages, and highland barley bran SDF can be considered as a potential functional additive in the food industry.

Steam Explosion Pre-Treatment of Sawdust for Biofuel Pellets

The current study explores steam explosion pre-treatment of wood sawdust to develop high-quality biofuel pellets. In order to determine optimized conditions (temperature and residence time) for steam-treated biomass, seven test responses were chosen, including bulk, particle and pellet densities as well as tensile strength, dimensional stability, ash content and higher heating value (HHV). Parameters tested for steam treatment process included the combination of temperatures 180, 200 and 220 °C and durations of 3, 6 and 9 min. Results showed that when the severity of steam pre-treatment increased from 2.83 to 4.49, most of the qualities except HHV and ash content were favorable for steam pretreated materials. The pellet density of pretreated sawdust in comparison to raw sawdust resulted in 20% improvement (1262 kg/m3 for pretreated material compared with 1049 kg/m3 for non-treated material). Another important factor in determining the best pellet quality is tensile strength, which can be as high as 5.59 MPa for pretreated pellets compared with 0.32 MPa for non-treated pellets. As a result, transportation and handling properties can be enhanced for steam pretreated biomass pellets. After optimization, the selected treatment was analyzed for elemental and chemical composition. Lower nitrogen and sulfur contents compared with fossil fuels make steam pretreated pellets a cleaner option for home furnaces and industrial boilers. High-quality pellets were produced based on optimized pre-treatment conditions and are therefore suggested for bioenergy applications.

Solid-State Fermentation of Steam-Exploded Opuntia ficus-indica Cladodes Using Trichoderma reesei CCT-2768 for the Production of Cellulolytic Enzymes.

The sustainable development of the drylands, i.e., regions with limited availability of water, depends on the exploitation of the few biomass types that can thrive in such conditions, such as the Opuntia ficus-indica, a plant of the Cactaceae family. In the present study, the cladodes of O. ficus-indica were used as a substrate by the fungus Trichoderma reesei CCT-2768 for the production of cellulolytic enzymes through solid-state fermentation. Firstly, the extraction of the mucilage, soluble components of industrial interest, was evaluated. Temperature, water-to-biomass ratio, and time of mixture were varied using an experimental design and impacted, especially, the pectin removal. Then, the lignocellulosic residue was used for the production of enzymes; the effect of the water activity, biomass pretreatment, mineral supplementation, temperature, and inoculum size on the enzymatic production were investigated using two sets of experimental designs. The steam explosion pretreatment exposed the fiber to the microbial action and boosted the enzyme production, provided that the medium was supplemented with salts. This combination has improved the production of xylanase, CMCase, FPase, and polygalacturonase by 27, 62, 98, and 185%, respectively. The temperature of 35°C was determined as the optimal for the production of FPase, xylanase, and polygalacturonase, while no effect was observed on the production of CMCase and β-glucosidase. The optimization of the enzymatic production performed in this study can potentially provide a new application for the Opuntia biomass and improve the sustainable development of the drylands.

Enhancing methane production of anaerobic digested sewage sludge by advanced wet oxidation & steam explosion pretreatment

Anaerobic digestion (AD) of sewage sludge is associated with lowered carbon conversion efficiency due to the recalcitrance of microbial cells in the Waste Activated Sludge (WAS) from the aeration basins with 50 % of the dry weight still being present after AD. The effect of Advanced Wet Oxidation & Steam Explosion (AWOEx) pretreatment on the methane yield at variable temperatures (165–200 °C), residence time (15–45 min) and oxygen dosage (1%–10% based on VS concentration) was tested in this study. Central composite design (JMP® Pro) was used to design 19 runs of AWOEx pretreatment of dewatered digested sewage sludge (DADSS) at different operating conditions. After pretreatment the DADSS was fed to 19 bioreactors operated in semi-continues mode at 37 °C. The highest average methane yields of 183 mL/g VS and 170 mL/g VS were found for the bioreactors receiving DADSS pretreated at 165 °C with a retention time of 15 min and 10 % O 2 (Condition 1), and, 182.5 °C with a retention time of 15 min and 5.5 % O 2 (Condition 2). This corresponds to an increase in the methane production of 156.2 % and 140.5 % compared to the methane production from the DADSS without pretreatment. Plotting the results using the response surface model showed that temperature and O 2 dosage had a significant effect on the methane yield while residence time was of lower importance. Importantly, thermic treatment without oxygen showed far lower methane yields of 114.5 mL/gVS and 120.26 mL/gVS, respectively of the two best conditions described above. Through this two-step AD process, we were able to achieve a net 94% improved methane yield compared to conventional AD of sewage sludge by implementing a second AWOEx pretreatment step (followed by secondary AD) with 26.9% decreased organics content, further reducing the cost of the final disposal of the treated sewage sludge. • AWOEx pretreated sludge tested for CH 4 yield at variable temperature, residence time and O 2 dosage. • JMP Pro was used to design 19 differential runs of AWOEx pretreated DADSS. • Pretreated DADSS was fed to 19 bioreactors operated in semi-continues mode at 37 °C. • Optimal average CH 4 yield of 183 mL/g VS was obtained for 165 °C, 15 min and 10% O 2 . • 94% improved methane yield compared to conventional AD of sewage sludge.

Optimization of ultrasound pretreatment and enzymatic hydrolysis of wheat straw: From lab to semi-industrial scale

In this paper, the dominance of the physical effects of ultrasound (US) pretreatment in improving the delignification of wheat straw at a 1:20 solid/liquid (biomass/water) ratio is reported showing low-frequency/high power (25 kHz, 2 or 3 kW) as preferred conditions. The sonochemical pretreatment with alkali was identified as an optimal method to make the cellulose more susceptible to further enzymatic hydrolysis, thereby increasing the yield of soluble sugars. Previous bench-scale studies have shown that US pretreatment has a positive effect on delignification, nevertheless this has not yet been demonstrated on a larger scale. The objective of this study was to demonstrate the effectiveness of US pretreatment for wheat straw delignification from lab to semi-industrial scale (40 kg biomass) in terms of sugar yield and energy efficiency. A 59.2% of lignin removal was recorded after the cavitational treatment of wheat straw with a subsequent 68 ± 5.7% yield in terms of enzymatic hydrolysis (52.6% glucose, 42.9% xylose and 4.5% arabinose).It was demonstrated that the positive effect of US alkali pretreatment of wheat straw on sugar yield was due to a combination of factors, including (i) an easier accessibility of the biomass carbohydrate network to enzymes due to the increased wheat straw porosity, (ii) the partial removal of lignin, which increases the relative proportion of carbohydrates in the treated biomass, and (iii) the disordering (amorphization) of the cellulose structure, which promotes carbohydrate hydrolysis as well as saponification of the acetyl groups in the hemicellulose. With respect to the Life Cycle Assessment (LCA) and the Cost Benefit Analysis the US pretreatment process herein reported was compared to an alternative Steam Explosion pretreatment. The results of the LCA analysis showed, that for all five environmental categories (energy consumption, global warming potential, water and fossil depletion, and the land occupation) the US pretreatment has advantages in comparison with the standard industrial Steam Explosion pretreatment.

Potential of some Latvian Industrial Crops Residuals for Conversion to Bio-Based Thermal Insulation Material

Some industrial crops residuals like wheat straw, buckwheat husks and reeds were used in the study as raw lignocellulosic materials to evaluate their potential as thermal insulation material. Steam explosion (SE) pre-treatment was used to disrupt and convert the raw material smooth shape to foamy fibrous shape. Two level Factorial design was used to evaluate the impact of raw material fraction size (10-20-30 mm), moisture content (10-30-50%), SE temperature (200-215-230 °C) and duration (00-30-60 s) on bulk density and thermal conductivity of the obtained loose-fill materials. The results show that all selected raw materials could be characterized as thermal insulation materials as the determined thermal conductivity was in the range of 0.042–0.058 W (m K)-1 including neat samples. In spite of effective fibrillation of raw materials SE pre-treatment did not improve their thermal conductivity. The determined bulk density of loose-fill crops varied in range of 23–184 kg m-3 depending on all variables; the SE pre-treatment showed the most significant effect on its reduction. Based on the study results the most suitable crops residues for bio-based thermal insulation purposes are suggested wheat straw and reeds demonstrating the lowest values of bulk density and thermal conductivity.

Investigation of Steam Explosion Pretreatment of Sawdust and Oat Straw to Improve Their Quality as Biofuel Pellets

Steam explosion pretreatment of sawdust and oat straw under mild, medium, and severe conditions was conducted to improve the quality of pellets generated from these feedstocks. This work examined the effects of temperature, time, and moisture content on the mechanical properties of biomass pellets. From the ANOVA conducted, the p-values of the regression models for all the response variables (dimensional stability, tensile strength, and pellet density) studied were significant (p < 0.05), except for the pellet density of steam-pretreated oat straw pellets. The interaction of these three factors did not significantly affect the response variables of oat straw pellets. In addition, the higher heating value (HHV) of treated biomass increased up to a maximum of about 9.5% and 7% as compared with the non-treated sawdust and oat straw, respectively. In addition, an increment of about 3.6-fold and 3.1-fold in pellet tensile strength of steam-pretreated sawdust and oat straw was observed, respectively. Microstructural examination of the pellets from steam-pretreated biomass revealed that the material contained particles that were more closely bonded and featured a cemented surface with fewer pores when compared to particles from untreated oat straw and sawdust.

Steam Explosion Pretreatment for Improving Wheat Bran Extrusion Capacity.

Extrusion improves the texture of wheat bran and enhances its product edibility, making it a promising processing method. However, the extrusion performance of wheat bran without any treatment is not satisfactory and limits the utilization of wheat bran in food processing. In this study, steam explosion pretreatment was used to treat wheat bran to investigate its promotion of wheat bran extrusion. The results showed that steam explosion could increase the extrusion ratio of wheat bran extrudate by 36%. Grinding the steam-exploded wheat bran extrudate yields wheat bran flour with smaller particle sizes and higher cell wall breakage. Fourier transform infrared spectroscopy and chemical composition results revealed that steam explosion degraded insoluble dietary fiber and disrupted the dense structure of the cell wall in wheat bran. The water-extracted arabinoxylan and soluble dietary fiber content of steam-exploded wheat bran were 13.95% and 7.47%, respectively, improved by 1567.42% and 241.75% compared to untreated samples. The total phenol and flavonoid contents, water solubility index, and cation exchange capacity of steam-exploded wheat bran extrudate were all superior to raw wheat bran extrudate. In summary, this study demonstrates that steam explosion improves the extrusion capacity of wheat bran and facilitates its utilization.

Biomass valorization by integrating ultrasonication and deep eutectic solvents: Delignification, cellulose digestibility and solvent reuse

Biomass valorization in converting biomass into value-added products and energy has gained researchers’ attention. In this study, valorization of oil palm empty fruit bunch (OPEFB) towards biofuels production was focused. Combination of deep eutectic solvent (DES) and ultrasonication was employed to pretreat the OPEFB. The pretreatment was conducted in a sonicator at 210 W, 50 °C for 30 min. Choline chloride-lactic acid (ChCl-LA) outperformed choline chloride-urea (ChCl-U) and choline chloride-glycerol (ChCl-G) because of its acidity and low viscosity properties. Besides having the highest cellulose digestibility (36.7% of reducing sugars yield), ChCl-LA pretreated biomass had the lowest lignin content of 18.8% and biomass crystallinity of 0.895. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) results further confirmed its biomass disruption ability. Ultrasonic-assisted DES pretreatment exhibited a synergetic effect, whereby the reducing sugars yield was double compared to without ultrasound. Also, its pretreatment performance was better than other pretreatment methods, such as acid, alkaline and steam explosion pretreatments. The DESs were effectively recovered with a slight decrease in delignification and cellulose digestibility efficiencies. These collectively proven the feasibility and effectiveness of ultrasound-assisted DES pretreatment in converting the biomass to sugars, which could be essential for biofuels production.

Qualitative Differences and Emission Persistence of Volatile Organic Compounds from Bio-Based Particleboards.

An attempt to reduce, replace, or even eliminate the synthetic resins from wood-based panels alongside broadening the array of raw lignocellulosics is still essential and attractive. Many pretreatments of lignocellulosics have been studied, among which steam explosion (SE) resulted in superior physical-mechanical properties of the obtained binder-less boards. However, the SE pretreatment leads to a relatively strong odor, which is even emitted from the obtained binder-less boards independent of the raw lignocellulosic, raising concern about the use of the boards. Emissions of volatile organic compounds (VOCs) were investigated in the framework of the study from binder-less boards obtained from different SE raw lignocellulosics and SE-untreated suberinic acids-bonded particleboard. VOCs were collected by headspace solid-phase microextraction (HS-SPME) and analyzed by gas chromatography–mass spectrometry (GC–MS) for 28 days with an interval of 2 weeks. The results showed that the number of detected VOCs and their chromatographic peak area varied significantly depending on the raw lignocellulosic, board density, and post-treatment (overlayering), decreasing over time. The lowest area of detected VOCs was demonstrated by the suberinic acids-bonded particleboard, while the highest area was detected from the high-density binder-less board obtained from SE hemp shives with the main compound of furfural (up to 70%) in all board types.

Effect of steam explosion pretreatment on polysaccharide isolated from Poria cocos: Structure and immunostimulatory activity.

This study aimed to examine the effects of steam explosion (SE) pretreatment on the structural characteristics and immunostimulatory activity of polysaccharide from Poria cocos. Results showed that the average molecular weights of native polysaccharide (PCP) and SE-pretreated polysaccharide (SEPCP) were 18.67 and 6.52 kDa, respectively. PCP and SEPCP shared the same profiles of monosaccharides (mannose, glucose, galactose, and fucose) in different composition ratios, that is, PCP in a molar percentage of 13.5:33:40.3:13.2 and SEPCP in a molar percentage of 2.1:90.3:5.8:1.8. The surface structure of PCP showed smooth and densely spherical particles, whereas SEPCP had a rough surface and porous honeycomb structure. The main linkage types of PCP comprised 1,6-α-d-Galp, 1,2,6-α-d-Glcp, and T-α-d-Manp, whereas SEPCP primarily contained 1,3-β-d-Glcp backbone and T-β-d-Glcp branches. Compared with PCP, we further revealed that SEPCP had a better immune enhancement on the phagocytic ability, NO production, and the secretion levels of TNF-α and IL-6 in RAW 264.7 cells. Collectively, our observations supported that SE pretreatment could help to change the structure and improve the immunostimulatory activity of polysaccharide from P. cocos. PRACTICAL APPLICATIONS: SE technology is extensively used to extract bioactive components with improved yields owing to this technology's benefits of low energy consumption and high efficiency. SE pretreatment was found to contribute to the destruction of cell-wall structure, which could help to enhance the extraction yields of P. cocos polysaccharide (PCP). Meanwhile, SE pretreatment also could change the structural features and improve the immunostimulatory activity of PCP. This study revealed that more bioactive PCP with strengthened immunoregulatory effect was obtained pretreated by SE. This study was able to provide the effective information on the application of steam explosion technology to promote the further development and utilization of PCP in the pharmaceutical and functional food fields.

High Concentration of Fermentable Sugars Prepared from Steam Exploded Lignocellulose in Periodic Peristalsis Integrated Fed-Batch Enzymatic Hydrolysis.

High concentrations of fermentable sugars are a demand for economical bioethanol production. A single process strategy cannot comprehensively solve the limiting factors in high-solid enzymatic hydrolysis. The multiple intensification strategies in this study achieved the goal of preparing high-concentration fermentable sugars of corn stalk with high solid loading and low enzyme loading. First, steam explosion pretreatment enhanced the hydrophilicity of substrates and enzymatic accessibility. Second, periodic peristalsis was used to improve the mass transfer efficiency and short the liquefaction time. Additionally, fed-batch feeding and enzyme reduced the enzyme loading. Ultimately, the intensification strategies above showed that the highest fermentable sugar content was 313.8g/L with a solids loading as much as 50% (w/w) and enzyme loading as low as 12.5 FPU/g DM. Thus, these multiple intensification strategies were promising in the high-solid enzymatic hydrolysis of steam-exploded lignocellulose.

Evaluation of the Hydrolysis Efficiency of Bacterial Cellulose Gel Film after the Liquid Hot Water and Steam Explosion Pretreatments.

The influence of bacterial cellulose gel film pretreatment methods on the efficiency of enzymatic hydrolysis was investigated. An increase in the efficiency of enzymatic hydrolysis due to liquid hot water pretreatment or steam explosion was shown. The glucose yield of 88% was obtained from raw, non-purified, bacterial cellulose treated at 130 °C. The results confirm the potential of bacterial cellulose gel film as a source for liquid biofuel production.

Steam‐exploded camellia (Camellia oleifera Abel.) seed protein improves the stability of camellia seed oil emulsions

SummaryWe aimed here to investigate the ability of steam‐exploded camellia seed protein (SECSP) in stabilising steam‐exploded camellia seed oil‐in‐water emulsion in comparison with soy protein isolate (SPI). Emulsions with different SECSP and SPI contents (0.5, 1, 1.5 and 2 g 100 mL−1) were formulated and the effect of protein concentration on emulsion droplet size, zeta (ζ)‐potential, physical stability and bioaccessibility was examined. The stability of emulsion increased with increasing protein concentration. SECSP emulsion was characterised by smaller droplet sizes, higher surface charge and better stability than SPI emulsion. Furthermore, SECSP emulsion exhibited good digestive stability. SECSP emulsion showed creaming only at protein concentrations above 0.5 g 100 mL−1 after 28 days of storage, while SPI emulsion showed stratification and flocculation during the same storage period. Hence, steam explosion pretreatment physical modification of camellia seed protein (CSP) provides a novel approach of utilising proteins for emulsions stabilisation, and digestive stability improvement under gastrointestinal conditions.

Bioethanol Production from Steam-Exploded Barley Straw by Co-Fermentation with Escherichia coli SL100

Second-generation bioethanol is considered a suitable option for replacing fossil fuels. Agricultural residues are being studied as feedstocks for sugar generation, which are in turn converted into ethanol. Among them, barley straw (BS) is a promising raw material, due to its high abundance, lignocellulosic composition and lack of other practical applications. Under these assumptions, the central aim of this study is to suggest an efficient bioethanol production scheme from BS at different levels of integration in co-fermentation with Escherichia coli SL100, including separate hydrolysis and co-fermentation (SHCF), simultaneous saccharification and co-fermentation (SSCF), and presaccharification and simultaneous saccharification and co-fermentation (PSSCF), using the water-insoluble solid (WIS) and slurry fractions obtained after steam explosion (SE) pretreatment. The best results in terms of ethanol yield were achieved following the SHCF process, using the WIS and the slurry as substrates, with yields of 89.1% and 78.8% of the theoretical maximum, respectively. Considering all of the above points, the following scheme is proposed for the conversion of BS into ethanol: SE pretreatment (160 °C, 30 min) of BS previously soaked overnight in 2.88% w/v phosphoric acid solution, filtration of the slurry, followed by enzymatic hydrolysis and co-fermentation of the two fractions obtained separately, with previous detoxification of the prehydrolysate with ammonium hydroxide (5 N). Under these conditions, 19.43 g of bioethanol was produced from 100 g of BS.

Xylo-oligosaccharides, fermentable sugars, and bioenergy production from sugarcane straw using steam explosion pretreatment at pilot-scale

This study investigated the production of xylo-oligosaccharides (XOS) from sugarcane straw (SCS) using steam explosion (SE) pretreatment at pilot-scale, as well as co-production of fermentable sugars and lignin-rich residues for bioethanol and bioenergy, respectively. SE conditions 200 °C; 15 bar; 10 min led to 1) soluble XOS yields of up to 35 % (w/w) of initial xylan with ∼50 % of the recovered XOS corresponding to xylobiose and xylotriose, considered the most valuable sugars for prebiotic applications; 2) fermentable glucose yields from the enzymatic hydrolysis of SE-pretreated SCS of up to ∼78 %; 3) increase in the energy content of saccharified SCS residues (16 %) compared to the untreated material. From an integrated biorefinery perspective, it demonstrated the potential use of SCS for the production of value-added XOS ingredients as well as liquid and solid biofuel products.