Search Results (318)

In this work, biochars were produced by pyrolysis of exhausted olive pomace and evaluated as low-cost adsorbents for the removal of methylene blue (MB) from aqueous solutions. The biochar obtained at 400 °C for 1 h, which exhibited the best adsorption performance, was characterized by FTIR, N₂ adsorption–desorption isotherms, SEM-EDX, and proximate analysis, revealing a mesoporous structure with a relatively low specific surface area but enriched in surface functional groups, likely due to the partial degradation of lignocellulosic components. Adsorption experiments were conducted to optimize operational parameters such as solid particle size (2–3 mm), agitation speed (75 rpm), and bioadsorbent dosage (1 g per 0.05 L of MB solution), which allowed for dye removal efficiencies close to 100%. Kinetic studies showed that MB adsorption followed a pseudo-second-order model, while equilibrium data at 30 °C were best described by the Langmuir isotherm (R² = 0.999; SE = 4.25%), suggesting monolayer coverage and strong adsorbate–adsorbent affinity. Desorption trials using water, ethanol, and their mixtures resulted in low MB recovery, whereas the addition of 10% acetic acid significantly improved desorption performance. Under optimal conditions, up to 52% of the retained dye was recovered. Full article

Developing a more efficient, cleaner, and energy-saving pretreatment process is the primary goal for lignocellulosic biofuels production. This study demonstrated the feasibility of circulating high-concentration acetone–butanol–ethanol (ABE) obtained via in situ product recovery (ISPR) as a pretreatment liquor. Taking ABE solvent separated from pervaporation (PV) and gas stripping (GS) as examples, results indicated that under dilute alkaline (1% NaOH) catalysis, the highly recalcitrant lignocellulosic matrices can be efficiently depolymerized, thereby improving fermentable sugars recovery in saccharification stage and ABE yield in subsequent fermentation stage. Results also revealed delignification of 91.5% (stream from PV) and 94.3% (stream from GS), with total monosaccharides recovery rates of 56.5% and 57.1%, respectively, can be realized when using corn stover as feedstock. Coupled with ABE fermentation, mass balance indicated a maximal 106.6 g of ABE (65.8 g butanol) can be produced from 1 kg of dry corn stover by circulating the GS condensate in pretreatment (the optimized pretreatment conditions were 1% w/v alkali and 160 °C for 1 h). Additionally, technical lignin with low molecular weight and narrow distribution was isolated, which enabled further side-stream valorisation. Therefore, integrating ISPR product circulation with lignocellulosic biobutanol shows strong potential for application under the concept of biorefinery. Full article

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

The rise in multidrug-resistant bacterial strains and persistent infections such as Lyme disease caused by Borrelia burgdorferi highlights the need for novel antimicrobial agents. The present study explores the antioxidant, antibacterial, and cytotoxic properties of extracts from submerged mycelial biomass of Fomitopsis pinicola, cultivated in synthetic and lignocellulosic media. Four extracts were obtained using hot water and 80% ethanol. The provided analysis of extracts confirmed the presence of various bioactive compounds, including flavonoids, alkaloids, and polyphenols. All extracts showed dose-dependent antioxidant activity (IC₅₀: 1.9–6.7 mg/mL). Antibacterial tests revealed that Klebsiella pneumoniae was most sensitive, with the L2 extract producing the largest inhibition zone (15.33 ± 0.47 mm), while the strongest bactericidal effect was observed against Acinetobacter baumannii (MBC as low as 0.5 mg/mL for L1). Notably, all extracts significantly reduced the viability of stationary-phase B. burgdorferi cells, with L2 reducing viability to 42 ± 2% at 5 mg/mL, and decreased biofilm mass, especially with S2. Cytotoxicity assays showed minimal effects on NIH 3T3 cells, with slight toxicity in HEK 293 cells for S2 and L1. These results suggest that F. pinicola extracts, particularly ethanolic L2 and S2, may offer promising natural antimicrobial and antioxidant agents for managing resistant infections. Full article

The transition to sustainable energy sources has intensified interest in lignocellulosic biomass (LCB) as a feedstock for second-generation biofuels. However, the inherent structural recalcitrance of LCB requires the utilization of an effective pretreatment to enhance enzymatic hydrolysis and subsequent fermentation yields. This manuscript presents a novel, single-step, and optimized nitrogen explosive decompression system (NED 3.0) designed to address the critical limitations of earlier NED versions by enabling the in situ removal of inhibitory compounds from biomass slurry and fermentation inefficiency at elevated temperatures, thereby reducing or eliminating the need for post-treatment detoxification. Aspen wood (Populus tremula) was pretreated by NED 3.0 at 200 °C, followed by enzymatic hydrolysis and fermentation. The analytical results confirmed substantial reductions in common fermentation inhibitors, such as acetic acid (up to 2.18 g/100 g dry biomass) and furfural (0.18 g/100 g dry biomass), during early filtrate recovery. Hydrolysate analysis revealed a glucose yield of 26.41 g/100 g dry biomass, corresponding to a hydrolysis efficiency of 41.3%. Fermentation yielded up to 8.05 g ethanol/100 g dry biomass and achieved a fermentation efficiency of 59.8%. Inhibitor concentrations in both hydrolysate and fermentation broth remained within tolerable limits, allowing for effective glucose release and sustained fermentation performance. Compared with earlier NED configurations, the optimized system improved sugar recovery and ethanol production. These findings confirm the operational advantages of NED 3.0, including reduced inhibitory stress, simplified process integration, and chemical-free operation, underscoring its potential for scalability in line with the EU Green Deal for bioethanol production from woody biomass. Full article

Sawdust is an abundant source of lignocellulosic biomass, presenting a sustainable alternative to fossil fuels for producing aromatics, fuels, and chemicals. Lignin, a crucial component, can be depolymerized into valuable aromatics or used for polymer synthesis due to its multiple hydroxyl groups. This study focuses on extracting lignin from Chlorophora excelsa sawdust via organosolv technology. The characterization of sawdust revealed 41.15% cellulose, 28.63% hemicellulose, and 26.13% lignin. The extraction process involved treating sawdust at varying temperatures (100–200 °C) with an ethanol–water solution and sulfuric acid. The optimal yield of 49.81% lignin occurred at 160 °C, confirming the chemical properties and composition of the extracted lignin. Full article

The projected depletion of fossil resources has initiated research on new and sustainable fuels which can be utilized in combination with conventional fuels. Lignocellulosic biomass, and more specifically lignin, can be depolymerized towards phenolic and aromatic bio-oils which can be converted downstream into bunker fuel blending components. Within this study, solvolysis under critical ethanol conditions and mild catalytic hydrotreatment were applied to heavy fractions of lignin pyrolysis bio-oils with the aim of recovering bio-oils with improved properties, such as a lower viscosity, that would allow their use as bunker fuel blending components. The mild reaction conditions, i.e., low temperature (250 °C), short reaction time (1 h) and low hydrogen pressure (30–50 bar), led to up 65 wt.% recovery of upgraded bio-oil, which exhibited a high carbon content (63–73 wt.%), similar to that of the parent bio-oil (68.9 wt.%), but a lower oxygen content and viscosity, which decreased from ~298,000 cP in the parent lignin pyrolysis oil to 526 cP in the hydrotreated oil, with a 10%Ni/Beta catalyst in methanol, and which was also sulfur-free. These properties permit the potential utilization of the oils as blending components in conventional bunker fuels. Full article

Reprocessing lignocellulosic waste to obtain new products for industrial purposes is a vital part of circular economy. This paper reports the cellulase production by newly isolated Bacillus methylotrophicus cultured on lignocellulosic agro-industrial by-products, out of which brewer’s spent grain (BSG) was selected as most beneficial. Plackett–Burman design was used for screening medium components, while Box–Behnken design was further applied to model the impact of the three most influential variables. The maximum approximated cellulase activity was 0.469 U/mL (1 U = 1 µmol of reducing sugars/1 min), at 48.6 g/L substrate, 5.3 g/L ammonium sulfate, pH 6.1. The partially purified cellulase was characterized, which demonstrated broad range of optimal pH (6.5–9.4), temperature (50–60 °C), and sensitivity to metals. Changes in lignin and pentosans content was demonstrated as a result of BSG hydrolysis with a cell-free cellulase preparation. The produced enzyme was used for hydrolysis of various chemically pretreated (NaOH and H₂SO₄) cellulosic substrates, where for reused alkali-pretreated BSG (after microbial enzyme production) the saccharification efficiency was at a level of 25%. The cellulolytic potential of the bacterial strain, along with its resistance to ethanol, present a beneficial combination, potentially applicable to aid saccharification of lignocellulosic by-products for biofuel production. Full article

Cacao is a food of global interest. Currently, the industry primarily utilizes the seed, which represents between 21% and 23% of the total fruit weight. In 2023, global production reached 5.6 million tons of fermented dry cacao beans, while approximately 25.45 million tons corresponded to cacao residues. The objective of this review was to compile and analyze alternatives for the utilization of cacao by-products. The methodology involved technological surveillance conducted in specialized databases between 2015 and 2025. Metadata were analyzed using VOSviewer software version 1.6.20. Priority was given to the most recent publications in high-impact indexed journals. Additionally, 284 patent documents were identified, from which 15 were selected for in-depth analysis. The reviewed articles and patents revealed a wide range of industrial applications for cacao by-products. Technologies including ultrasonic and microwave-assisted extraction, phenolic microencapsulation, cellulose nanocrystal isolation and targeted microbial fermentations maximize the recovery of polyphenols and antioxidants, optimize the production of high-value bioproducts such as citric acid and ethanol, and yield biodegradable precursors for packaging and bioplastics. The valorization of lignocellulosic by-products reduces pollutant discharge and waste management costs, enhances economic viability across the cacao value chain, and broadens functional applications in the food industry. Moreover, these integrated processes underpin circular economy frameworks by converting residues into feedstocks, thereby promoting sustainable development in producer communities and mitigating environmental impact. Collectively, they constitute a robust platform for the comprehensive utilization of cacao residues, fully aligned with bioeconomy objectives and responsible resource stewardship. Full article

The presence of various inhibitory compounds in lignocellulosic hydrolysates poses a significant challenge for bioethanol production, requiring yeasts with exceptional multistress tolerance. This study introduces the novel application and demonstrates the robust performance of the nonconventional yeast Saccharomycodes ludwigii APRE2 for efficient bioethanol production directly from undetoxified sugarcane bagasse hydrolysate (SBH) at 37 °C. This approach critically eliminates the need for the costly detoxification pretreatments often required in industrial processes. Initial experiments confirmed S. ludwigii APRE2’s capability to ferment undetoxified SBH. To optimize fermentation efficiency, a central composite design (CCD) approach was implemented. This statistical method identified the following precise optimal parameters: sugar concentration (143.95 g/L), diammonium phosphate (4.99 g/L), pH (4.98), yeast extract (8.94 g/L), and magnesium sulfate (2.22 g/L). Under these optimized conditions, impressive results were achieved: a maximum ethanol concentration of 38.11 g/L, productivity of 1.59 g/L·h, and yield of 0.45 g/g. Notably, the ethanol productivity and theoretical yield achieved by S. ludwigii APRE2 using this inhibitor-rich, undetoxified SBH (containing acetic acid, formic acid, furfural, and 5-(hydroxymethyl)furfural) were superior to those previously reported for other ethanologenic yeasts under similar challenging conditions. This research establishes S. ludwigii APRE2 as a highly promising and industrially viable candidate for sustainable bioethanol production from lignocellulosic biomass, with its key novelty being its superior performance on undetoxified feedstocks, potentially reducing overall production costs. Full article

The development of yeast cell factories for efficient xylose utilization and xylitol production is crucial for advancing sustainable biotechnological processes. Xylose, a major component of lignocellulosic biomass, presents challenges for microbial conversion due to its complex metabolic pathways. This study presents the genomic perspective and xylitol production capability of a novel xylose utilizing yeast Cyberlindnera fabianii TBRC 4498. Genome sequencing and functional annotation revealed key metabolic networks and genes involved in the xylose metabolism pathway, providing insights into the strain’s performance. The Cy. fabianii TBRC 4498 had excellent growth and xylose assimilation at a broad range of xylose concentrations from 40 to 140 g/L, with the highest growth rate at 80 g/L of xylose. The highest xylitol production yield (83.19 g/L) was detected from 120 g/L of xylose at 30 °C for 72 h, equivalent to 0.65 g xylitol/g xylose and 1.16 g/L/h productivity. Remarkably, Cy. fabianii TBRC 4498 produced high-purity xylitol, achieving over 95% homogeneity without forming undesirable byproducts, such as acid or ethanol. These results demonstrated the potential of Cy. fabianii TBRC 4498 as a whole-cell biocatalyst for xylitol production using high xylose concentrations, offering a promising microbial cell factory for large-scale xylitol production from lignocellulosic sugar. Full article

Ethanol and xylitol are valuable bioproducts synthesized by non-conventional yeasts from lignocellulosic sugars. However, their biosynthesis requires distinct cultivation conditions. This study evaluated the production of ethanol and xylitol by Clavispora lusitaniae using saccharified sugarcane bagasse (SSCB) under three aeration conditions: microaerobic (C1), anaerobic (C2), and a combination of anaerobic followed by a microaerobic phase (C3). Ethanol production was maximum under anaerobic conditions (C2), followed by combined anaerobic–microaerobic conditions (C3). Meanwhile, xylitol production was most efficient under microaerobic conditions (C1). Notably, anaerobic conditions were ineffective for xylitol production. Enzyme activities of xylose reductase (XR) and xylitol dehydrogenase (XDH), key enzymes in xylose metabolism, were highest under microaerobic conditions with activities of 2.88 U/mg and 1.72 U/mg, respectively, after 48 h of culture. Gene expression analysis of XYL1 and XYL2 correlated with the corresponding enzyme activities (XR) and (XDH) with increased levels of 32.38 and 7.88 fold, respectively, compared to the control in C1. These findings suggest that C. lusitaniae co-produces ethanol efficiently under anaerobic conditions, while xylitol biosynthesis is optimized under microaerobic conditions when using xylose-rich saccharified lignocellulosic substrates. Full article

Alkaline treatment is well suited for extracting high-molecular-weight hemicelluloses, specifically hardwoods xylans, which, due to their polymer structure and chemical characteristics, enable the production of films with desirable mechanical, barrier, and optical properties for packaging applications. Despite its relevance, the optimization of antisolvent addition has received little attention in the literature. This study explores the use of eucalyptus industrial residue as feedstock, utilizing a statistical design to determine the optimal extraction conditions for hemicelluloses while minimizing the lignin content in the recovered liquor. The process uses alkali loads that are compatible with those in conventional Kraft pulp mills. Optimal extraction conditions involve a temperature of 105 °C, 16.7% NaOH charge, and 45 min at maximum temperature. The resulting liquor was subjected to ethanol precipitation under varying pH conditions (initial pH, 9, 7, 5, and 2) and different ethanol-to-liquor ratios (1:1 to 4:1). The acidification was performed using hydrochloric, sulfuric, and acetic acids. Ethanol served as the main antisolvent, while isopropyl alcohol and dioxane were tested for comparison. Results show that 2.3 ± 0.2% of xylans (based on oven-dry biomass) could be extracted, minimizing lignin content in the liquor. This value corresponds to the extraction of 15.6% of the xylans present in the raw material. The highest xylan precipitation yield (78%) was obtained at pH 7, using hydrochloric acid for pH adjustment and an ethanol-to-liquor ratio of 1:1. These findings provide valuable insight into optimizing hemicellulose recovery through antisolvent precipitation, contributing to more efficient biomass valorization strategies within lignocellulosic biorefineries. Full article

Agricultural waste poses significant environmental, economic, and social challenges globally, with estimates indicating that 10–50% of agricultural products are discarded annually as waste. This review explores strategies for managing agricultural waste to mitigate its adverse impacts and promote sustainable development. Agricultural residues, such as those from sugarcane, rice, and wheat, contribute to pollution when improperly disposed of through burning or burying, contaminating soil, water, and air. However, these residues also represent untapped resources for bioenergy production, composting, mulching, and the creation of value-added products like biochar, bioplastics, single-cell protein and biobased building blocks. The paper highlights various solutions, including integrating agricultural waste into livestock feed formulations to reduce competition for human food crops, producing biofuels like ethanol and biodiesel from lignocellulosic materials, and adopting circular economy practices to upcycle waste into high-value products. Technologies such as anaerobic digestion for biogas production and gasification for synthesis gas offer renewable energy alternatives and ample feedstocks for gas fermentation while addressing waste management issues. Composting and vermicomposting enhance soil fertility, while mulching improves moisture retention and reduces erosion. Moreover, the review emphasizes the importance of policy frameworks, public-private partnerships, and farmer education in promoting effective waste management practices. By implementing these strategies, agricultural waste can be transformed into a resource, contributing to food security, environmental conservation, and economic growth. Full article

Lactate is a valuable compound used in food, chemical, and pharmaceutical industries. High-value, optically pure L- or D-lactate can be synthesized microbially via specific dehydrogenases. The non-conventional yeast Scheffersomyces stipitis, which is known for fermenting both hexoses and pentoses, is a promising host for biochemical production from lignocellulosic biomass but does not naturally produce lactate. In this study, we engineered S. stipitis to produce lactate by expressing two codon-optimized bacterial L-lactate dehydrogenase genes under the control of strong native promoters. The engineered strain produced 7.42 g/L (0.46 g/g yield) and 11.67 g/L (0.58 g/g yield) lactate from glucose and xylose, respectively. The highest titer, 19.27 g/L (0.52 g/g yield), was achieved from 50 g/L xylose after 74 h. Increasing the fermentation temperature from 28 °C to 32 °C improved yield by 30%, while a neutralizing agent further enhanced yield by 25% and prevented lactate degradation following carbon depletion. Although the wildtype strain produced a significant amount of ethanol on both glucose and xylose, the engineered strain produced ethanol as a side product exclusively on glucose and not on xylose. This phenomenon could be advantageous for biotechnological applications and may reflect shifts in gene expression depending on the carbon source or even on the presence of lactate. Full article