Fermentable Sugars Research Articles

ИССЛЕДОВАНИЕ ЭФФЕКТИВНОСТИ ВЛИЯНИЯ РАСТВОРОВ ЛИМОННОЙ КИСЛОТЫ НА СТЕПЕНЬ ИЗВЛЕЧЕНИЯ ПЕКТИНА ИЗ ФЕРМЕНТИРОВАННОГО СВЕКЛОВИЧНОГО ЖОМА

Pressed sugar beet pulp is a promising source of pectin. Currently, the growth of scientific and technological progress has made it promising to use such methods of controlled transformation of plant raw materials, in which the impact on the quality and yield of the target component is minimal, in contrast to the classic acid-alcohol method of producing pectin. Of greatest interest are biotechnological methods for extracting biologically active substances from plant materials, providing a higher yield while maintaining their properties. However, previous studies have established that during enzymatic hydrolysis-extraction of sugar beet pulp, about 50 % of pectin remains in the fermented sugar beet pulp. This necessitates research aimed at additional extraction of pectin from fermented beet pulp obtained as a result of enzymatic hydrolysis of pressed sugar beet pulp. The article resents the results of studies of the effectiveness of the influence of citric acid solutions on the degree of pectin extraction from fermented sugar beet pulp. Extraction of pectin from fermented sugar beet pulp was carried out under various conditions. When carrying out the extraction process, the extraction temperature was taken as constant factors – 55 ºC, the ratio (wt./vol.) fermented beet pulp: aqueous solution of citric acid equal to 1 : 10 and the intensity of mixing of the system, characterized by a stirrer rotation speed, equal to 0.33 s -1 . The concentration of an aqueous solution of citric acid and the extraction time were taken as variable factors, and the degree of pectin extraction was taken as a response function. Based on the results of mathematical processing of experimental data, an equation was obtained that adequately describes the effect of the concentration of an aqueous solution of citric acid and extraction time on the degree of pectin extraction. As a result of the studies, it was established that the optimal modes for extracting pectin from fermented beet pulp, ensuring a degree of pectin extraction of 10.81 %, are a concentration of an aqueous solution of citric acid of 0.33 % and an extraction time of 80 minutes. Key words: PECTIN-CONTAINING RAW MATERIALS, FERMENTED BEET PULP, PECTIN, CITRIC ACID, EXTRACTION DEGREE, EFFICIENCY

Tailoring whole slurry bioprocessing for sugary stovers to augment sugar production by integrating soluble and insoluble carbohydrates

Obtaining sufficient concentrations of fermentable sugars from the polysaccharides of lignocellulosic materials represents a long-term challenge in achieving sustainable biorefineries. This work aimed to enhance sugar titers by employing high sugar-containing stovers (HSS) and combining its intrinsic soluble sugars with the two insoluble carbohydrates, namely cellulose and hemicellulose. Whole-slurry hydrolysis (WSH) was performed under low-to-high solid conditions using non-detoxified pretreated slurry, which exhibited a decrease in cellulose hydrolysis efficiency (CHE) from 89.08% to 42.1% as the solid loadings increased from 7% to 20%. A further WSH with detoxified slurry showed a significant increase in CHE from 42.1% to 59.52% at 20% solid loading, indicating that inhibitors present in the pretreated slurry had negative effects on CHE. Lower CHE with non-detoxified slurry accompanied by higher losses of cellulase and β-glucosidase activities, particularly at higher solid loadings. Therefore, systematic modification of WSH was performed by incorporating 2% syringic acid during pretreatment and 0.4% polyethylene glycol during saccharification, reformulating enzyme cocktails, and implementing a fed-batch experiment. These modifications resulted in a notable improvement in sugar production under high-solid loading (20%) and non-detoxified conditions, reaching 142.87 g/L total sugars with a CHE of 90.7%. These findings have revealed the potential of integrating soluble sugars with holocellulose for obtaining high-titer fermentable sugars in lignocellulosic biorefineries.

Comprehensive understanding of co-producing fermentable sugar, furfural, and xylo-oligosaccharides through the pretreatment with CTAB-based deep eutectic solvent containing Brønsted and Lewis acid

The deep eutectic solvents (DESs) with additional functionalities synthesized using the cationic surfactant cetyltrimethylammonium bromide (CTAB) have gained attention due to their remarkable enzymatic enhancement capability. By combining CTAB, lactic acid, and FeCl3, a DES containing both Brønsted and Lewis acids was synthesized and the pretreatment parameters were optimized using response surface methodology. The results demonstrated the selective and efficient delignification (83.2 %) and xylan removal (76.3 %) from canola straw by CTAB:LA:Fe3+, resulting in an increased saccharification efficiency of 81.8 %. Besides, abundant furfural (3.36 g/L) and xylo-oligosaccharides (3.41 g/L) were co-produced during pretreatment, providing comprehensive insights into the efficient co-production of fermentable sugars, furfural, and xylo-oligosaccharides. A thorough analysis of mass balance and energy flow was conducted to evaluate the entire process. Then, molecular dynamics (MD) simulations and quantum chemical calculations were performed on lignocellulosic biomass models and elucidate the interactions between the biomass and CTAB:LA:Fe3+ at the molecular level through the independent gradient model (IGM), thus explaining the high removal efficiency of hemicellulose and lignin. Furthermore, the physicochemical properties of the DESs were investigated, and molecular-level insights into the mechanism of CTAB:LA:Fe3+ pretreatment of lignocellulosic biomass were proposed in conjunction with biomass characterization such as FT-IR and CLSM, as well as MD simulations.

Enzymatic hydrolysis of fermentable sugars prepared from bamboo by pretreatment with hot water and green liquor

Enzymatic hydrolysis of fermentable sugars prepared from bamboo by pretreatment with hot water and green liquor

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.

Potential of barley straw pretreated with a lignin inhibitor as an adjunct during beer production

SummaryBarley straw is an agricultural residue of low added value used for alcohol production through chemical pretreatments. However, chemical pretreatments are expensive and generate residues, preventing the possible application of this product in the food. This study aims to use piperonylic acid as a lignin inhibitor applied in a barley field to obtain a pretreated straw more accessible to structural carbohydrates, releasing fermentable sugars and partially replacing malt in beer. Straws showed structural and chemical changes with SEM, FTIR and compositional analysis. These changes enabled the fermentable sugars release when inserted in wort with 2.5% of barley straw, using cellulase isolated or a xylanase and cellulase mixture in 1:2 proportion, maintaining a final enzyme concentration of 16 U mL−1. Barley straw pretreated with lignin inhibitor can be used as a brewing adjunct, increasing the release of fermentable sugars and bioactive compounds.

Sugarcane: A Climate Resilient Devine Crop

Worldwide increasing demands of food, fodder, fuel and other bio-chemicals for erratically increasing population, urbanization and industrialization. Only sugarcane (Saccharum spp.) has great potential as a major feedstock for sugar, biofuel and allied related production. Sugarcane is the lead driver for production of sugar and sweeteners globally. It is considered among the best options and replace the fossil fuels for production of biofuels today due to an exceptional biomass production capacity, high carbohydrate (sugar + fiber) content, and a favourable energy input/output ratio. The conversion of sugarcane biomass into fermentable sugars for second-generation ethanol production is a promising alternative to meet future demands of biofuel production in the world. Biofuels have gained much importance due to the depleting fossil fuel resources and the over-accumulation of CO2 and other greenhouse gases in the environment. Biofuel and paper production from sugarcane can be achieve the targets to replace fossil fuels to scavenge carbon dioxide released into the atmosphere and to attain environmental and economic sustainability. Fermentable sugars (40-60%) of molasses which is diluted with distilled water and by fermentation process (Saccharomyces cerevisae) produce rum (wine). Application of sugarcane by-products, such as press mud, vinasse and bagasse, to improves chemical, physical, and biological properties of soil and enhanced the crop quality and yield. For transfer the live micro-organism from agar slant of laboratory to rhizosphere then sugar press mud play key role in formulating microbial inoculant as suitable carrier. Food yeast Torulopsis utilis, is prepared from molasses used as baker’s and brewer’s yeast in bakery industry. Sugarcane improves the economy of rural population by providing lead source of fodder for livestock management as a sugarcane tops and by-products of sugarcane (molasses treated with urea, mineral mixture treated sugarcane top hays etc.). Scientific interventions have not only helped to improve the cane crop but industrial procedures have also been upgraded resulting in improved production of biofuel, paper, wine etc and other sugarcane by-products used to improve the economy of rural and urban population. However, building a bridge between science and industry requires investments in research, development and transfer of new technologies to the industry as well as specialized personnel to deal with new technological challenges.

Dysbiosis and nutrition in steatotic liver disease: addressing the unrecognized small intestinal bacterial overgrowth (SIBO) challenge.

Steatotic liver disease (SLD) is characterized by hepatic fat accumulation, potentially causing major consequences such as liver decompensation. Currently, we lack medications for the treatment of SLD. Therapeutic recommendations for patients include a hypocaloric diet, weight loss, and physical activity. In particular, the Mediterranean diet is frequently recommended. However, this diet might exacerbate intestinal problems in a subset of patients with coexisting small intestinal bacterial overgrowth (SIBO). Previous studies have reported that SIBO is more predominant in patients with fatty liver than in healthy individuals. Both our research and the findings of others have highlighted a challenge related to nutritional therapy in patients with fatty liverwho also suffer from SIBO inasmuch as SIBO induces several phenomena (like bloating or abdominal pain) that can adversely affect patients' quality of life and might be exacerbated by the Mediterranean diet. This may lower their adherence to the intervention. As a solution, we suggest introducing additional diagnostics (e.g., breath test) in patients with SLD who complain of SIBO-like symptoms. The next step is to modify their diets temporarily starting with several weeks of "elimination and sanitation." This would involve restricting products rich in fermentable sugars and polyols, while simultaneously treating the bacterial overgrowth. In summary, while the hypocaloric Mediterranean diet is beneficial for patients with fatty liver, those with coexisting SIBO may experience exacerbated symptoms. It is vital to consider additional diagnostics and dietary modifications for this subset of patients to address both liver and intestinal health concurrently.

Simple one-step treatment for saccharification of mango peels using an optimized enzyme cocktail of Aspergillus niger ATCC 9642.

Developing efficient microbiological methods to convert polysaccharide-rich materials into fermentable sugars, particularly monosaccharides, is vital for advancing the bioeconomy and producing renewable chemicals and energysources. This study focused on optimizing the production conditions of an enzyme cocktail from Aspergillus niger ATCC 9642 using solid-state fermentation (SSF) and assessing its effectiveness in saccharifying mango peels through a simple, rapid, and efficient one-step process. A rotatable central composite design was employed to determine optimal conditions of moisture, time, and pH for enzyme production in SSF medium. The optimized enzyme cocktail exhibited cellulase activity (CMCase) at 6.28 U/g, filter paper activity (FPase) at 3.29 U/g, and pectinase activity at 117.02 U/g. These optimal activities were achieved with an SSF duration of 81 h, pH of 4.66, and a moisture content of 59%. The optimized enzyme cocktail effectively saccharified the mango peels without the need for chemical agents. The maximum saccharification yield reached approximately 81%, indicating efficient conversion of mango peels into sugars. The enzyme cocktail displayed consistent thermal stability within the tested temperature range of 30-60°C. Notably, the highest sugar release occurred within 36 h, with glucose, arabinose, galactose, and xylose being the primary monosaccharides released during saccharification. This study highlights the potential application of Aspergillus niger ATCC 9642 and SSF for enzymatic production, offering a simple and high-performance process for monosaccharide production. The optimized enzyme cocktail obtained through solid-state fermentation demonstrated efficient saccharification of mango peels, suggesting its suitability for industrial-scale applications.

Biobased propylene glycol production in a sugarcane biorefinery through lactic acid, glycerol, or sorbitol: A techno-economic and environmental evaluation of intermediates and downstream processing methods

Propylene glycol (PG) is a versatile chemical which can be produced by direct fermentation of sugars or through intermediates like lactic acid (LA), glycerol and sorbitol. Few studies have examined producing PG from different intermediates in terms of economic feasibility. In this study, seven process scenarios were assessed in a biorefinery annexed to an existing sugar mill. Aspen simulations were developed for each scenario as the basis for mass and energy balances, techno-economic, and environmental evaluations. Scenario 1 (LA intermediate) had the lowest minimum selling price (MSP) of 1991 US$t−1 and greenhouse gas (GHG) emissions of 1.24 kgCO2/kgPG which was the best intermediate investigated. Scenario 2a-2d (glycerol intermediate) was used to offer insights on the economic benefits of different design changes to the process. Scenario 2a investigates the use of reactive distillation as opposed to normal distillation in the other scenarios. Scenario 2c and 2d offer insights on the purchasing of green hydrogen as an alternative to producing onsite and effect of increased hydrogen ratios respectively. The MSP for the scenarios ranged from 2121–2863 US$.t−1 and GHG emissions of 0.8–2.2 kgCO2/kgPG. Scenario 3 (sorbitol intermediate) had the poorest performance with an MSP of 2751 US$t−1 and GHG emissions of 2.22 kgCO2/kgPG. Scenario 4 (combined first and second-generation feed) had an MSP of 2065 US$t−1 and 1.04 kgCO2/kgPG for GHG.

Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activities

BackgroundThe polysaccharides in lignocellulosic biomass hold potential for production of biofuels and biochemicals. However, achieving efficient conversion of this resource into fermentable sugars faces challenges, especially when operating at industrially relevant high solid loadings. While it is clear that combining classical hydrolytic enzymes and lytic polysaccharide monooxygenases (LPMOs) is necessary to achieve high saccharification yields, exactly how these enzymes synergize at high solid loadings remains unclear.ResultsAn LPMO-poor cellulase cocktail, Celluclast 1.5 L, was spiked with one or both of two fungal LPMOs from Thermothielavioides terrestris and Thermoascus aurantiacus, TtAA9E and TaAA9A, respectively, to assess their impact on cellulose saccharification efficiency at high dry matter loading, using Avicel and steam-exploded wheat straw as substrates. The results demonstrate that LPMOs can mitigate the reduction in saccharification efficiency associated with high dry matter contents. The positive effect of LPMO inclusion depends on the type of feedstock and the type of LPMO and increases with the increasing dry matter content and reaction time. Furthermore, our results show that chelating free copper, which may leak out of the active site of inactivated LPMOs during saccharification, with EDTA prevents side reactions with in situ generated H2O2 and the reductant (ascorbic acid).ConclusionsThis study shows that sustaining LPMO activity is vital for efficient cellulose solubilization at high substrate loadings. LPMO cleavage of cellulose at high dry matter loadings results in new chain ends and thus increased water accessibility leading to decrystallization of the substrate, all factors making the substrate more accessible to cellulase action. Additionally, this work highlights the importance of preventing LPMO inactivation and its potential detrimental impact on all enzymes in the reaction.

Bioethanol Production from Characterized Pre-treated Sugarcane Trash and Jatropha Agrowastes

Low production costs and a potential feedstock supply make lignocellulosic ethanol (bioethanol) an important source of advanced biofuels. The physical and chemical preparation of this kind of lignocellulosic feedstock led to a high ethanol yield. In order to increase the yield of fermentable sugars, pretreatment is an essential process step that alters the lignocellulosic structure and improves its accessibility for the expensive hydrolytic enzymes. In this context, the chemical composition of sugarcane trash (dry leaves, green leaves, and tops) and jatropha (shell and seed cake) was determined to be mainly cellulose, hemicellulose, and lignin. Hydrogen peroxide and sodium hydroxide were applied in an attempt to facilitate the solubilization of lignin and hemicelluloses in five agrowastes. The extraction of hydrogen peroxide was much better than that of sodium hydroxide. A comparative study was done using SEM, EDXA, and FTIR to evaluate the difference between the two methods. The pretreated wastes were subjected to saccharification by commercial cellulases (30 IU/g substrate). The obtained glucose was fortified with nutrients and fermented statically by Saccharomyces cerevisiae F-307 for bioethanol production. The results revealed the bioethanol yields were 325.4, 310.8, 282.9, 302.4 and 264.0 mg ethanol/g treated agrowastes from green leaves of sugarcane, jatropha deolied seed cake, tops sugarcane, dry leaves of sugarcane, and jatropha shell, respectively. This study emphasizes the value of lignocellulosic agricultural waste as a resource for the production of biofuels as well as the significance of the extraction process.

Efficient ethanol production from masson pine sawdust by various organosolv pretreatment and modified pre-hydrolysis simultaneous saccharification and fermentation

Pretreatment is a key step in lignocellulosic biorefinery. In this study, the combination of organosolv pretreatment and lignin repolymerization inhibitor was put forward to fractionate the lignocellulosic biomass, providing readily hydrolyzed substrate. Results showed that, acidic 1,4-butanediol pretreatment extensively removed lignin from softwood, reducing the physical blockage effect of lignin. Besides, lignin repolymerization inhibitors were employed to modify lignin, giving rise to lower unproductive binding effect of lignin. As a result, maximum 79.9 ± 0.3 % of original lignin in raw biomass could be removed, and 97.9 ± 0.5 % of glucan in pretreated solid could be converted into fermentable sugars after acidic butanediol pretreatment assisted by sodium 2-naphthol-7-sulphonate and enzymatic hydrolysis at 2 % glucan loading. Furthermore, a modified pre-hysrolysis simultaneous saccharification and fermentation process at 10 % glucan loading produced 45.6 ± 1.7 g/L ethanol, with ethanol yield of 18.7 ± 0.4 g/100 g raw biomass. Finally, the mass balance revealed that the lignocellulosic biorefinery based on acidic butanediol pretreatment assisted by sodium 2-naphthol-7-sulphonate could achieve full utilization of lignocellulosic components to co-produce ethanol, lignin materials and hemicellulose-derived mono-saccharides.

Modelling and dynamic simulation to produce fermentable sugars from lignocellulosic substrates through dilute acid hydrolysis

AbstractThis research paper presents a comprehensive investigation aimed at enhancing the 2G bioethanol production process through the implementation of a dynamic process simulator. The simulator, developed using the Julia programming language, enables the prediction of acid hydrolysis behaviour by manipulating critical variables, including liquid–solid ratio (LSR), acid concentration (CA), and processing time (t). Through meticulous simulations and subsequent experimental validation, optimal operating conditions were revealed, with an H2SO4 concentration of 2% v/v, a LSR of 4% v/w, and 60‐min processing time at 121.1°C. This configuration led to remarkable outcomes, including a xylose concentration of 47.45 g L−1 and an 87.4% hemicellulose removal percentage. Moreover, the simulator unveiled the adverse influence of low LSR values on xylose production and the generation of degradation products. The recalibration of kinetic parameters, guided by experimental data, further fine‐tuned the simulator's predictive accuracy. Overall, this study underscores the potential of the simulator in optimizing various raw materials and presents a promising avenue for advancing 2G bioethanol industry practices.

New trends in microbial lipid-based biorefinery for fermentative bioenergy production from lignocellulosic biomass

Using oleaginous microbial lipid-based biorefinery from lignocellulosic biomass (LCB) to produce fermentative bioenergy (i.e., biodiesel) represents an innovative second-generation fuel production technology. These lipids are predominantly intracellular triglycerides that accumulate through the metabolism of sugars in fermentation following pretreatment and enzymatic hydrolysis of LCB. This review investigates the recent advances in the microbial lipid production from LCB, focusing on the factors influencing the lead microbial lipid producers, different pretreatment methods (i.e., physical, chemical, biological, and combined pretreatment), enzymatic hydrolysis approaches, novel bioprocessing strategies (i.e., microbes-specific and fermentation model specific), and engineering techniques of the oleaginous microbes (i.e., genetic and metabolic alterations). The study demonstrates that oleaginous yeasts can synthesize significantly higher quantities of lipids when incorporated into the system, known as separated hydrolysis and lipid production, following various combined pretreatment methods. Interestingly, CRISPR is found to be the most suitable way of engineering microbes genetically and metabolically for increased lipid synthesis. The study also explores economically viable strategies for fermentative lipid production, addressing associated challenges, and outlines future directions, including comprehensive techno-economic and life cycle assessments. This review offers invaluable insights into microbial lipid production from LCB, highlighting the potential for significant technological and environmental enhancements through ongoing research and development efforts.

Influence of Cellulose-Cellulase Enzyme Digestibility in the Production of Glucose from Lignocellulosic Biomass Waste

A comprehensive understanding of the factors and ability of cellulase enzyme to completely hydrolyze the structural lignocellulosic biomass has been a major research focus over the years. A comparative analysis of cellulose-cellulase digestibility of Kraft-pretreated sawdust from twenty different Nigeria wood wastes was carried out with increasing enzyme (Trichorderma viride) loading of 0.4 mg cm−3, 1.0 mg cm−3, 2.0 mg cm−3, and 4.0 mg cm−3 at constant substrate application of 10 mg cm−3 biomass concentration, temperature of 40°C and 2 h incubation period. This was carried out in order to establish the optimum cellulase-cellulose ratio for maximum biodegradation of the lignocellulosic biomass to produce glucose, a fermentable sugar. The influence of the cellulose-cellulase interaction from 0.4 mg cm−3 to 1.0 mg cm−3 enzyme treatment resulted in 144% increase in glucose yield from E. suaveolen and 121% from S. pustlatas. while 2.0 mg cm−3 cellulase concentration gave 674%, 641% and 617% increase from E.suaveolen, H. ciliate and A. germinans respectively. A general trend of increasing sugar formation was observed with an increasing enzyme loading due to enhanced cellulose accessibility by the cellulase enzyme leading to effective saccharification of the lignocellulosic materials for more sugar production. However, further increase of 4.0 mg cm−3 enzyme concentration failed to produce a commiserate amount of fermentable sugar.

Effect of Mashing-in pH on the Biochemical Composition and Staling Properties of the Sweet Wort

Mashing is a decisive brewing step, affecting wort quality. Critical mashing parameters include time, temperature, pH, mash density and oxygen uptake. While the pH-dependent biochemical changes during mashing have been researched, the oxidative processes remain unclear. This work explores the impact of pH conditions during mashing on the biochemical composition and oxidative properties of wort. In laboratory trials, mashing was conducted at different mashing-in pH (4.5, 5.0, 5.2, 5.4, 6.0). The sweet worts were analyzed for extract, fermentable sugars, limit dextrins, amino acids, soluble proteins, polyphenols, color, aldehydes, transition metals, reducing potential, and rate of radical formation. Differences were found in enzymatic activities (particularly proteolysis), color, aldehydes, transition metal ions, the rate of radical formation and the rate of oxygen consumption. Notably, when adjusting the pH at mashing-in, the obtained wort tends to gravitate toward the pH of the unadjusted wort, underscoring its buffering capacity. This was reflected by similar properties of the produced worts, indicating pH playing a lesser role during mashing compared to time/temperature. However, under extreme acidified conditions (pH 4.5 at mashing-in), the produced wort markedly deviates. An intriguing negative correlation between the reducing potential and the content of transition metal ions with the rate of radical formation is discussed.

Temperature and photoperiods optimization for the cultivation of Chlorella vulgaris for growth and biomass production from cassava wastes

Microalgae biomass is widely being used as a third generation biofuel because they are the most promising renewable feedstock for biofuel production. Its use is greatly considered as it has high growth rate, photosynthetic efficient, not competing for arable land, efficient carbon dioxide fixation and potential to accumulate high amount of carbohydrate. Microalgae carbohydrates are contained in their cell wall mainly as cellulose and plastids as starch which are readily converted into fermentable sugars. The cultivation of Chlorella vulgaris on cassava wastes for growth and biomass production depends on factors such as temperature and photoperiods. Cassava waste mixtures were cultivated on Chlorella vulgaris stock culture at different concentration ratio at pH of 6.5 and salinity of 10mg/l, cultivation ratio of 160:40 for cassava peel water to cassava waste water CP:CW at 670nm absorbance for 7 days. Temperature variations of 200C, 300C and 350C were checked to determine the optimum temperature for the growth and biomass production of Chlorella vulgaris on the optimum cassava waste mixture concentration. Photoperiod variation of 12:12, 6:18 and 18:6 were checked to determine optimum photoperiod for the growth and biomass production of Chlorella vulgaris on the optimum cassava waste mixture concentration. From the results obtained in this optimization study, optimum growth and biomass was recorded at temperature of 30 ℃. Photoperiod of 12:12 was responsible for optimum growth while photoperiod of 18:6 light and dark conditions gave high biomass production. This study shows that optimized conditions are necessary high growth and biomass production of the microalgae on cassava waste.

An integrated pretreatment strategy for enhancing enzymatic hydrolysis efficiency of poplar: Hydrothermal treatment followed by a twin-screw extrusion

To reduce the dependence on chemical inputs during biomass pretreatment, an integrated process on the basis of hydrothermal pretreatment followed by twin-screw extrusion for poplar was proposed. A comparative study was conducted on the pore structure, crystallinity, relative surface lignin concentration, cellulose accessibility, and enzymatic hydrolysis efficiency of the pretreated materials. Results suggested that the relative surface lignin concentration of fibers pretreated by hydrothermal treatment (conducted at 170 ℃ for 90 min) coupled with extrusion (HE) treatment was decreased compared to the sole hydrothermal (H) process, which had a positive impact on the subsequent enzymatic hydrolysis. Additionally, the HE process resulted in an increase in pore size by 34.4%, pore volume by 447.5%, and specific surface area by 93.5%, which enhanced the penetration and interaction of water into the fibers and thus increased cellulose accessibility by 143.2%. SEM and TEM observations revealed that fibers were separated and finely fibrillated, large amounts of fragmentary structure and cracks appeared on the fiber. In addition, the cell wall structure was deformed and damaged, when pretreated by HE process. Overall, this work showed that hydrothermal treatment followed by twin-screw extrusion was an achievable strategy for high fermentable sugar production of hardwood.

Semi-continuous subcritical hydrolysis of orange waste biomasses for integrated production of fermentable sugars and platform chemicals

Results for the obtaining of fermentable sugars (FSs) and platform chemicals (PCs) from the subcritical hydrolysis of orange wastes (peel and bagasse) are presented. Unlike what is typically reported in similar studies involving lignocellulosic biomasses, the hydrolysis process was performed in a semi-continuous configuration, which allowed the examination of how temperature (180 to 220 °C) and pressure (15 to 25 MPa) influenced the compounds’ kinetic profile. Furthermore, studies have been found that evaluated these points for such biomasses. The best yields of hydrolyzed solution were obtained for biomasses pretreated by soxhlet with hydrolysis conducted at 180 °C and 15 MPa (orange peel, OP) and 200 °C and 20 MPa (orange bagasse, OB), yielding 5.31 and 4.26 g (100 g biomass)−1, respectively. Among the FSs, xylose was the monosaccharide predominantly obtained for both biomasses: 21.12 g L−1 for OP pretreated with SCO2 (hydrolysis at 180 °C and 15 MPa); and 24.45 g L−1 for untreated OB (hydrolysis at 220 °C and 25 MPa). Regarding the PCs, furfural was the main compound obtained for both biomasses: 10.86 g L−1 for untreated OP and 7.33 g L−1 for OB pretreated with SCO2, with both hydrolysis conducted at 220 °C and 25 MPa.