Search Results (69)

The sugarcane industry plays a crucial economic role worldwide, with sucrose and ethanol as its main products. However, its processing generates large volumes of by-products—such as bagasse, molasses, vinasse, and straw—that contain valuable components for biotechnological valorization. This review integrates approximately 100 original research articles published in JCR-indexed journals between 2015 and 2025, of which over 50% focus specifically on sugarcane-derived agroindustrial residues. The biotechnological approaches discussed include submerged fermentation, solid-state fermentation, enzymatic biocatalysis, and anaerobic digestion, highlighting their potential for the production of biofuels, enzymes, and high-value bioproducts. In addition to identifying current advances, this review addresses key technical challenges such as (i) the need for efficient pretreatment to release fermentable sugars from lignocellulosic biomass; (ii) the compositional variability of by-products like vinasse and molasses; (iii) the generation of metabolic inhibitors—such as furfural and hydroxymethylfurfural—during thermochemical processes; and (iv) the high costs related to inputs like hydrolytic enzymes. Special attention is given to detoxification strategies for inhibitory compounds and to the integration of multifunctional processes to improve overall system efficiency. The final section outlines emerging trends (2024–2025) such as the use of CRISPR-engineered microbial consortia, advanced pretreatments, and immobilization systems to enhance the productivity and sustainability of bioprocesses. In conclusion, the valorization of sugarcane by-products through biotechnology not only contributes to waste reduction but also supports circular economy principles and the development of sustainable production models. Full article

Biomass liquefaction is a promising thermochemical route to convert lignocellulosic residues into bio-oil. This study evaluates the liquefaction behavior of 13 biomasses with varying particle sizes (0.3–2.0 mm) and moisture contents (5–11%) under mild solvolysis conditions. High-performance liquid chromatography (HPLC-RID) and thermogravimetric analysis (TGA) were used to characterize bio-oil composition and biomass properties, respectively. Maximum conversion (72%) was achieved for Miscanthus, while Ulva lactuca reached only 23% due to its low carbohydrate content. Hemicellulose-rich feedstocks showed higher yields, whereas high lignin content generally reduced conversion. Furfural was the main compound identified in the aqueous phase (up to 51 g/L), reflecting extensive pentose degradation. Laboratory and industrial-scale liquefaction of cork and eucalyptus revealed scale-dependent differences. Industrial cork bio-oil showed increased xylose (0.70 g/L) and furfural (0.40 g/L), while industrial eucalyptus exhibited elevated levels of acetic (0.46 g/L) and formic acids (0.71 g/L), indicating enhanced deacetylation and demethoxylation reactions. These findings offer valuable insights for optimizing feedstock selection and process conditions in biomass liquefaction. The valorization of lignocellulosic residues into bio-oil contributes to the development of scalable, low-carbon technologies aligned with circular economy principles and bio-based industrial strategies. Full article

In this study, a response surface methodology (RSM) using a central composite design (CCD) was implemented to investigate the influence of process variables on ethyl levulinate (EL) production from the ethanolysis of waste corn cob samples, using sulphuric acid as a catalyst. The effects of four independent variables, namely, the temperature (A), the corn cob content (B), corn cob/H₂SO₄ mass ratio (C) and the reaction time (D) on the yields of EL (Y₁), diethyl ether (DEE) (Y₂) and solid residue (Y₃) were explored. Using multiple regression analysis, the experimental results were fitted to quadratic polynomial models. The predicted yields based on the fitted models were well within the experimental uncertainties. Optimum conditions for maximising the EL yield were found to be 176 °C, 14.6 wt. %, 21:1 and 6.75 h for A to D, respectively. A moderate-to-high EL yield (29.2%) from corn cob was achieved in optimised conditions, a result comparable to those obtained from model C₆ carbohydrate compounds. Side products were also produced, including diethyl ether, furfural, levulinic acid, 5-hydroxymethyl furfural, ethyl acetate, ethyl formate and water. Total unknown losses of only 5.69% were reported after material balancing. The results suggest that lignocellulosic waste such as corn cob can be used as a potential feedstock for the production of ethyl levulinate by direct acid-catalysed ethanolysis, but that the treatment of side products will need to be considered. Full article

Solid Fe catalysts supported on SiO₂ with Lewis and Brönsted acidity were synthesized using sol–gel methodology. FTIR spectroscopy, XRD, Raman spectroscopy, BET isotherms, and SEM characterized the materials. Subsequently, they were used to dehydrate xylose to obtain furfural. It was observed that increasing the metal loading from 0.5% to 1.5% by mass increases the selectivity of furfural up to 40.09%. In addition, the calcination temperature influenced the conversion because materials calcined at 450 °C presented higher xylose conversion than those calcined at 750 °C. Finally, the employed catalysts were active and effective in obtaining furfural from hydrolysates via hydrothermal treatments of a coffee crop’s residual biomass, producing an average of 9.11 mg/g of furfural per gram of biomass. Full article

The lactic acid (LA) production from corn stover using Lewis acid catalysts was optimized. Initially, an equimolar mixture of Al(III)/Sn(II) was used as a catalytic system at 190 °C with 5 wt% biomass. Increasing the catalyst concentration led to higher LA production, showing the optimal results at 16 mM. A low catalyst concentration mainly produced furfural and HMF, dehydration products from the corn stover sugars. Higher catalyst concentration increased LA yield but also produced the degradation of the glucose dehydration products into levulinic and formic acids, reducing LA selectivity. Al(III) was essential for LA formation, while Sn(II) was less effective due to its lower solubility, shown by the presence of Sn(II) in the solid residue after treatments. A total of 16 mM Al(III) yielded the highest LA levels at 190 °C, 7.4 g/L, and 20.7% yield. Increasing the temperature to 210 °C accelerated the LA production while also achieving the lowest energy consumption, which was 0.47 kWh/g LA at the highest LA production point. However, longer treatments at this temperature caused LA degradation. AlCl₃ has been identified as an ideal catalyst for biomass conversion to LA, being inexpensive and low in toxicity. Full article

This study investigates the hydrothermal gasification (HTG) of apricot tree resin, focusing on the yield and chemical composition of the resulting gas and aqueous phases. K₂CO₃ and KOH were used as catalysts within a temperature range of 300–600 °C, with a constant reaction time of 60 min. The results show that temperature and catalyst choice significantly influence gas yield, liquid composition, and solid residue formation. Higher temperatures increased the gas yield while decreasing aqueous and solid residues. The catalytic effect of K₂CO₃ and KOH enhanced the gaseous product conversion, with KOH achieving the highest gas yield and lowest residue formation at 600 °C. Among the liquid-phase compounds, carboxylic acids and 5-methyl furfural were the most abundant, reaching peak concentrations at 300 °C in the presence of K₂CO₃. The addition of alkali catalysts reduced key acidic intermediates such as glycolic, acetic, and formic acids. The inverse relationship between temperature and liquid/solid product formation underscores the importance of optimizing reaction conditions for efficient biomass conversion. These findings contribute to the growing field of biomass valorization by highlighting the potential of underutilized tree resins in sustainable biofuel production, advancing knowledge in renewable hydrogen production, and supporting the broader development of bio-based energy solutions. Full article

The use of tomato plant residues (i.e., stems, leaves, etc.) as a substrate for catalytic pyrolysis of biomass was investigated. A comprehensive study was conducted to investigate the impact of catalysts on the performance of different pyrolysis fractions (i.e., gas, biosolid, waxes, and bioliquid) as well as the distribution of products within the bioliquid. The catalysts employed in this study were derived from two distinct types of zirconia. The first type was synthesized by a conventional sol-gel method, while the second type was prepared with a modified method aimed at improving the presence of mesopores. This modification involved the incorporation of Pluronic 123. These materials were designated ZrO₂ and ZrO₂P25, respectively. Both types of zirconia were used as supports for tungstophosphoric acid (H₃PW₁₂O₄₀, TPA), a heteropolyacid with a Keggin structure, in the preparation of catalysts with strong acid sites. The results demonstrated that the bioliquid yield of the non-catalytic fast pyrolysis of tomato plant waste was approximately 23% and that the obtained bioliquid contained a wide variety of molecules, which were detected and quantified by GC-MS. In the presence of the catalysts, both the bioliquid yield and the distribution of bioliquid products were substantially modified. Furthermore, the possible sugar degradation pathways leading to the formation of the molecules present in the pyrolytic bioliquids were thoroughly examined. The results obtained from this study indicate that the physicochemical characteristics of the catalysts, specifically their pore size and acidity, have a significant impact on the selectivity of the catalytic processes towards valuable molecules, including anhydro-sugars and furanic derivatives such as furfural and furfuryl alcohol. Full article

Lignocellulosic waste biomass, a versatile natural resource derived from plants, has gained significant attention for its potential in the sustainable production of biobased chemicals. Furfural (FAL), xylo-oligosaccharides (XOSs), and reducing sugars are important platform chemicals, which can be obtained through the valorization of lignocellulosic solid biomass in a green and sustainable way. Waste yellow bamboo (YB) is one kind of abundant, inexpensive, and renewable lignocellulosic biomass resource. In order to improve the high-value utilization rate of raw YB, biochar-based solid acid catalyst (AT-Sn-YB) was utilized to assist the hydrothermal pretreatment for the valorization of YB in water. Under the optimal reaction conditions (200 °C, 60 min, and AT-Sn-YB dosage of 5.4 wt%), the FAL yield reached 60.8%, and 2.5 g/L of XOSs was obtained in the pretreatment system. It was observed that the surface structure of YB became rough and loose, exposing a significant number of pores. The accessibility increased from 101.8 mg/g to 352.6 mg/g after combined treatment. The surface area and hydrophobicity of lignin were 70.7 m²/g and 2.5 L/g, respectively, which were significantly lower than those of untreated YB (195.4 m²/g and 4.1 L/g, respectively). The YB solid residues obtained after treatment were subjected to enzymatic saccharification, achieving an enzymatic hydrolysis efficiency of 47.9%. Therefore, the hydrothermal pretreatment assisted by the AT-Sn-YB catalyst shows potential application value in FAL production and bamboo utilization, providing important references for other biomass materials. Full article

Pretreatment of lignocellulosic biomass remains the primary obstacle to the profitable use of this type of biomass in biorefineries. The challenge lies in the recalcitrance of the lignin-carbohydrate complex to pretreatment, especially the difficulty in removing the lignin to access the carbohydrates (cellulose and hemicellulose). This study had two objectives: (i) to investigate the effect of reactive extrusion on lignocellulosic biomass in terms of delignification percentage and the structural characteristics of the resulting extrudates, and (ii) to propose a novel pretreatment approach involving extrusion technology based on the results of the first objective. Two types of biomasses were used: agricultural residue (corn stover) and forest residue (black spruce chips). By optimizing the extrusion conditions via response surface analysis (RSA), the delignification percentages were significantly improved. For corn stover, the delignification yield increased from 2.3% to 27.4%, while increasing from 1% to 25.3% for black spruce chips. The highest percentages were achieved without the use of sodium hydroxide and for temperatures below 65 °C. Furthermore, the optimized extrudates exhibited important structural changes without any formation of p-cresol, furfural, and 5-hydroxymethylfurfural (HMF) (enzymes and microbial growth-inhibiting compounds). Acetic acid however was detected in corn stover extrudate. The structural changes included the disorganization of the most recalcitrant functional groups, reduction of particle sizes, increase of specific surface areas, and the appearance of microscopic roughness on the particles. Analyzing all the data led to propose a new promising approach to the pretreatment of lignocellulosic biomasses. This approach involves combining extrusion and biodelignification with white rot fungi to improve the enzymatic hydrolysis of carbohydrates. Full article

As a typical phenolic residue and pollutant, 2,4-D wastewater has a complex composition and high salt content, which makes it difficult for a single wastewater treatment method to meet the discharge standard. To address this challenge, this study explores an integrated electrochemical treatment approach that specifically targets 2,4-D high-salt organic wastewater with the aim of achieving the resource utilization of the wastewater and optimizing the operating parameters of each treatment unit. The results show that under the best experimental conditions, the chemical oxygen demand (COD) is significantly reduced to 200 mg/L, and the COD removal efficiency is as high as 99.67%. In addition, the recovery efficiency of phenolic substances 2,4-dichlorophenol, glycolic acid, and sodium chloride in wastewater reached 99.70%, 99.99%, 96.89%, and 80%, respectively. Phenols are used as raw materials for 2,4-D production, glycolic acid is widely used as a cleaning agent in industry, and the purity of recycled sodium chloride is as high as 99.08%, which can be reused as industrial salt. According to the treatment cost estimate, the benefit of recycling can offset the cost of wastewater treatment and may generate a certain economic surplus. This method is of great significance for the treatment of furfural wastewater and the realization of zero discharge of wastewater, which not only contributes to environmental protection but also promotes the sustainable utilization of resources. Full article

The core of saline–alkali soil improvement lies in salt leaching by water and reducing alkalinity by improved materials such as acid material or desulphurized gypsum. This study conducted simulation experiments to clarify the impact of furfural residue combined with desulfurization gypsum on saline–alkali soil water–salt and infiltration characteristics in Ningxia. Based on a consistent leaching water volume of 4500 m³/hm² and a furfural residue application amount of 7.5 t/hm², the experiment established three desulfurization gypsum application amounts of 15 t/hm², 22.5 t/hm², and 30 t/hm², with a control group that received no improved materials. The effects of different application amounts of desulfurization gypsum on water and salt distributions, alkalinity, infiltration rate, cumulative infiltration volume, and wetting front of saline–alkali soil were elucidated, and the Philip infiltration model was employed to fit the variations in cumulative infiltration volume. The results indicated the following: (1) Compared to the control group, the application of furfural residue and desulfurization gypsum resulted in an average reduction of 36.7% in soil alkalinity. The enhanced hydraulic conductivity of saline–alkali soil promoted the infiltration of water into deeper soil layers. The desalination effect in the 0–60 cm soil layer was significant; however, excessive application of desulfurization gypsum could lead to the accumulation of salts in soil layers below 80 cm. (2) The downward movement depth of the wetting front, cumulative infiltration volume, and infiltration rate all demonstrated a power function relationship with the infiltration time, with a coefficient of determination (R²) greater than 0.97. Additionally, the infiltration rate exhibited a linear correlation with the square root of the reciprocal of infiltration time, achieving an R² exceeding 0.99. (3) The Philip infiltration model is suitable for describing the relationship between cumulative infiltration volume and infiltration time. Therefore, the application of 7.5 t/hm² of furfural residue and 22.5 t/hm² of desulfurization gypsum can effectively improve the saline–alkali soils in Ningxia. Full article

Utilizing coffee by-products in the fermentation process of coffee offers a sustainable strategy by repurposing agricultural waste and enhancing product quality. This study evaluates the effect of applying a starter culture, derived from coffee residues, on the dynamics of reducing and total sugars during coffee fermentation, as well as the composition of aromatic compounds, organic acids, and the sensory profile of coffee inoculated with yeast (Saccharomyces cerevisiae) and lactic acid bacteria (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus), in comparison to a spontaneously fermented sample. Volatile compounds were identified and quantified using dynamic headspace gas chromatography-mass spectrometry (HS/GC-MS), with predominant detection of 2-furancarboxaldehyde, 5-methyl; 2-furanmethanol; and furfural—compounds associated with caramel, nut, and sweet aromas from the roasting process. A reduction in sugars (glucose, fructose, and sucrose) occurred over the 36 h fermentation period. Lactic acid (2.79 g/L) was the predominant organic acid, followed by acetic acid (0.69 g/L). The application of the inoculum improved the sensory quality of the coffee, achieving a score of 86.6 in evaluations by Q-graders, compared to 84 for the control sample. Additionally, descriptors such as red apple, honey, and citrus were prominent, contributing to a uniform and balanced flavor profile. These findings indicate that controlled fermentation with starter cultures derived from coffee by-products enhances sustainability in coffee production. It achieves this by supporting a circular economy, reducing reliance on chemical additives, and improving product quality. This approach aligns with sustainable development goals by promoting environmental stewardship, economic viability, and social well-being within the coffee industry. Full article

Resource use is crucial for the sustainable growth of energy and green low-carbon applications since the improper handling of biomass waste would have a detrimental effect on the environment. This paper used nano-ZnO and ammonium persulfate ((NH₄)₂S₂O₈, APS) as a template agent and heteroatom dopant, respectively. Using a one-step carbonization process in an inert atmosphere, the biomass waste furfural residue (FR) was converted into porous carbon (PC), which was applied to the supercapacitor electrode. The impact of varying APS ratios and carbonization temperatures on the physicochemical properties and electrochemical properties of PC was studied. O, S, and N atoms were evenly distributed in the carbon skeleton, producing abundant heteroatomic functional groups. The sample with the largest specific surface area (SSA, 855.62 m² g⁻¹) was made at 900 °C without the addition of APS. With the increase in adding the ratio of APS, the SSA and pore volume of the sample were reduced, owing to the combination of APS and ZnO to form ZnS during the carbonization process, which inhibited the pore generation and activation effect of ZnO and damaged the pore structure of PC. At 0.5 A g⁻¹ current density, PC900-1 (FR: ZnO: APS ratio 1:1:1, prepared at 900 °C) exhibited the maximum specific capacitance of 153.03 F g⁻¹, whereas it had limited capacitance retention at high current density. PC900-0.1 displayed high specific capacitance (141.32 F g⁻¹ at 0.5 A g⁻¹), capacitance retention (80.7%), low equivalent series resistance (0.306 Ω), and charge transfer resistance (0.145 Ω) and showed good rate and energy characteristics depending on the synergistic effect of the double layer capacitance and pseudo-capacitance. In conclusion, the prepared FR-derived PC can meet the application of a supercapacitor energy storage field and realize the resource and functional utilization of biomass, which has a good application prospect. Full article

The industrial processes used to produce paper and cellulose generate many lignocellulosic residues. These residues are usually burned to produce heat to supply the energy demands of other processes, increasing greenhouse gas emissions and resulting in a high environmental impact. Instead of burning these lignocellulosic residues, they can be converted into saccharides, which are feedstock for high-value products and biofuels. Keggin heteropolyacids are efficient catalysts for obtaining saccharides from cellulose and hemicellulose and converting them into bioproducts or biofuel. Furfural, 5-hydroxymethylfurfural, levulinic acid, and alkyl levulinates are important platform molecules obtained from saccharides and raw materials in the biorefinery processes used to produce fine chemicals and biofuels. This review discusses the significant progress achieved in the development of the processes based on heteropolyacid-catalyzed reactions to convert biomass and their residues into furfural, 5-hydroxymethylfurfural, levulinic acid, and alkyl levulinates in homogeneous and heterogeneous reaction conditions. The different modifications that can be performed to a Keggin HPA structure, such as the replacement of the central atom (P or Si) with B or Al, the doping of the heteropolyanion with metal cations, and a proton exchange with metal or organic cations, as well as their impact on the catalytic activity of HPAs, are detailed and discussed herein. Full article

In this research, the biochar-based tin-loaded heterogeneous catalyst Sn-NUS-BH was used for the efficient catalytic conversion of corncob (CC) in a green biphasic system of cyclopentyl methyl ether–water (CPME-H₂O). By optimizing the system conditions (CPME to H₂O ratio, Sn-NUS-BH dosage, reaction time, and reaction temperature), the stubborn structure of corncobs was maximally disrupted. The chemical composition and structural characteristics (accessibility, lignin surface area, and hydrophobicity) of CC before and after treatment were assessed, demonstrating that the natural physical barriers of CC were disrupted and lignin was effectually eliminated. The accessibility was enhanced from 137.5 mg/g to 518.5 mg/g, the lignin surface area declined from 588.0 m²/g to 325.0 m²/g, and the hydrophobicity was changed from 4.7 L/g to 1.3 L/g. Through the treatment at 170 °C for 20 min, furfural (11.7 g/L) and xylooligosaccharides (4.5 g/L) were acquired in pretreatment liquor. The residual CC could be enzymatically saccharified into reducing sugars in a yield of 65.2%. The combination pretreatment with the tin-based biochar chemocatalyst Sn-NUS-BH combined with the green solvent system CPME-H₂O shows great promise in the valorization of biomass. Full article