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The hydrothermal pretreatment process stands out as a pivotal step in breaking down the hemicellulosic fraction of lignocellulosic biomasses, such as sugarcane bagasse and eucalyptus sawdust. This pretreatment step is crucial for preparing these materials for subsequent processes, particularly in food applications. This technique aims to disintegrate plant wall components like cellulose, hemicellulose, and lignin, and facilitating access in later phases such as enzymatic hydrolysis, and ultimately making fermentable sugars available. In this study, sugarcane bagasse and eucalyptus sawdust biomass underwent hydrothermal pretreatment at specific conditions, yielding two key components: dry biomass and hemicellulose liquor. The primary focus was to assess the impact of hydrothermal pretreatment followed by enzymatic hydrolysis, using the Celic Ctec III enzyme cocktail, to obtain fermentable sugars. These sugars were then transformed into membranes via strain Gluconacetobacter xylinus bacterial biosynthesis. Notably, the addition of a nitrogen source significantly boosted production to 14.76 g/ in hydrolyzed sugarcane bagasse, underscoring its vital role in bacterial metabolism. Conversely, in hydrolyzed eucalyptus, nitrogen source inclusion unexpectedly decreased yield, highlighting the intricate interactions in fermentation media and the pivotal influence of nitrogen supplementation. Characterization of membranes obtained in synthetic and hydrolyzed media through techniques such as FEG-SEM, FTIR, and TGA, followed by mass balance assessment, gauged their viability on an industrial scale. This comprehensive study aimed not only to understand the effects of pretreatment and enzymatic hydrolysis but to also evaluate the applicability and sustainability of the process on a large scale, providing crucial insights into its feasibility and efficiency in practical food-related scenarios, utilizing nanocellulose bacterial (BNC) as a key component.

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With the increasing emphasis on sustainability and eco-friendliness, a novel biodegradable packaging materials has received unprecedented attention. Nanocellulose, owing to its high crystallinity, degradability, minimal toxicity, and outstanding biocompatibility, has gained considerable interest in the field of sustainable packaging. This review provided a comprehensive perspective about the recent advances and future development of cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs). We first introduced the utilization of agricultural waste for nanocellulose production, such as straw, bagasse, fruit byproducts, and shells. Next, we discussed the preparation process of nanocellulose from various agricultural wastes and expounded the advantages and shortcomings of different methods. Subsequently, this review offered an in-depth investigation on the application of nanocellulose in food packaging, especially the function and packaged form of nanocellulose on food preservation. Finally, the safety evaluation of nanocellulose in food packaging is conducted to enlighten and promote the perfection of relevant regulatory documents. In short, this review provided valuable insights for potential research on the biobased materials utilized in future food packaging.

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Second generation biorefineries play an important role in the production of renewable energy and fuels, utilizing forest and agro-industrial residues and by-products as raw materials. The integration of novel bioproducts, such as: xylitol, ß-carotene, xylooligosaccharides, and biopigments into the biorefinery's portfolio can offer economic benefits in the valorization of lignocellulosic materials, particularly cellulosic and hemicellulosic fractions. Fungal biopigments, known for their additional antioxidant and antimicrobial properties, are appealing to consumers and can have applications in various industrial sectors, including food and pharmaceuticals. The use of lignocellulosic materials as carbon and nutrient sources for the growth medium helps to reduce production costs, increasing the competitiveness of fungal biopigments in the market. In addition, the implementation of biopigment production in biorefineries allows the utilization of underutilized fractions, such as hemicellulose, for value-added bioproducts. This study deals with the potential of fungal biopigments production in second generation biorefineries in order to diversify the produced biomolecules together with energy generation. A comprehensive and critical review of the recent literature on this topic has been conducted, covering the major possible raw materials, general aspects of second generation biorefineries, the fungal biopigments and their potential for incorporation into biorefineries.

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The analysis of the secretome allows us to identify the proteins, especially carbohydrate-active enzymes (CAZymes), secreted by different microorganisms cultivated under different conditions. The CAZymes are divided into five classes containing different protein families. Thermothelomyces thermophilus is a thermophilic ascomycete, a source of many glycoside hydrolases and oxidative enzymes that aid in the breakdown of lignocellulosic materials. The secretome analysis of T. thermophilus LMBC 162 cultivated with submerged fermentation using tamarind seeds as a carbon source revealed 79 proteins distributed between the five diverse classes of CAZymes: 5.55% auxiliary activity (AAs); 2.58% carbohydrate esterases (CEs); 20.58% polysaccharide lyases (PLs); and 71.29% glycoside hydrolases (GHs). In the identified GH families, 54.97% are cellulolytic, 16.27% are hemicellulolytic, and 0.05 are classified as other. Furthermore, 48.74% of CAZymes have carbohydrate-binding modules (CBMs). Observing the relative abundance, it is possible to state that only thirteen proteins comprise 92.19% of the identified proteins secreted and are probably the main proteins responsible for the efficient degradation of the bulk of the biomass: cellulose, hemicellulose, and pectin.

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Lactic acid bacteria (LAB) coexist with Clostridium spp. in hydrogen production processes from complex substrates; however, the role of LAB is still unclear. This study analyzed the fermentation products in a wide range of initial pH (pHi, 5.5-6.9) and total solids (TS%, 8-22%) to determine the activity of these two microbial groups over time (from 24 to 120 h). Agave bagasse served as the feedstock for hydrogen production via consolidated bioprocess (CBP), while the inoculum source was the indigenous mature microbiota. In the early stage of the CBP, hydrogen production from lactic acid occurred only at pHi ≥ 6.0 (ρ = 0.0004) with no effect of TS%; lactic acid accumulated below this pHi value. In this stage, lactic acid production positively correlated with a first cluster of LAB represented by Paucilactobacillus (r = 0.64) and Bacillus (r = 0.81). After 72 h, hydrogen production positively correlated with a second group of LAB led by Enterococcus (r = 0.71) together with the hydrogen producer Clostridium sensu stricto 1 (r = 0.8) and the acetogen Syntrophococcus (r = 0.52) with the influence of TS% (ρ < 0.0001). A further experiment showed that buffering the pH to 6.5 increased and lengthened the lactic acid production, doubling the hydrogen production from 20 to 41 mL H2/gTSadded. This study confirmed the prevalence of distinct groups of LAB over time, whose microbial activity promoted different routes of hydrogen production.

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This research involved conducting continuous adsorption experiments to assess fluoride elimination from drinking water achieved by utilizing biocomposites created from the peels of oranges and apples, which were impregnated with zirconium (Zr), to form BOP-Zr and BAP-Zr, respectively. The findings from the experimental data indicate that BOP-Zr and BAP-Zr are effective biosorbents with a solid ability to remove fluoride selectively. Additionally, these biosorbents were found to be stable, as they do not release Zr into the treated water. Notably, these environmentally friendly biosorbents are derived from renewable sources and enhance the value of waste materials. The study employed various empirical models, including Bohart-Adamas, Thomas, Yoon-Nelson, BDST, Clark, Yan, and Woolborska, to elucidate the mechanisms and crucial parameters involved in fluoride adsorption within packed bed columns. The Yan model demonstrated the highest correlation among these models, indicating a chemical adsorption process with kinetics following a pseudo-second-order pattern. BOP-Zr and BAP-Zr exhibited a maximum adsorption capacity of 59.3 and 47.5 mg/g, respectively, under a flow rate of 4 mL/min and an inlet fluoride concentration of 25 mg/L. The analysis of mass transfer coefficients revealed that the primary step governing the adsorption procedure was diffusion through pores. Consequently, the study conclusively establishes that BOP-Zr and BAP-Zr biocomposites, originating from lignocellulosic biomass remains, present a practical and competitive choice for eliminating fluoride from water. These materials surpass waste materials in performance and rival more expensive options in efficiency and performance.

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One of the activities most representative of the agricultural sector in Colombia is the production of biodegradable fique fiber. The efficiency of the defiberization process of the fique leaves is very low since a mere 4% of the total weight of the leaf (cabuya) is used and marketed. The remaining 96%, composed of fique juice and bagasse, is considered to be waste and discarded, impacting the environment. The aim of this work was to study fique bagasse as a source of cellulose nanoparticles (CNCs). CNCs were obtained by acid hydrolysis and added at 10% to films made from cassava thermoplastic starch (TPS) by the casting method. Structural changes in the CNCs, TPS, and their mixtures were characterized by FTIR-ATR and their morphology and particle size by SEM and TEM microscopy, respectively. Thermal properties were analyzed using DSC and TGA, along with their effect on mechanical properties. Changes in the FTIR spectra indicated that the chemical method adequately removed hemicellulose and lignin from the fiber surface of fique bagasse. The CNCs showed a diameter and length of 7.5 ± 3.9 and 52.7 ± 18.1 nm, respectively, and TPS 10% CNC obtained an increase in mechanical strength of 116%. The obtainment of CNCs from lignocellulosic materials can thus be viewed as a favorable option for the subsequent reinforcement of a polymeric matrix.

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This review presents the advances in polymeric materials achieved by extrusion and injection molding from lignocellulosic agroindustrial biomass. Biomass, which is derived from agricultural and industrial waste, is a renewable and abundant feedstock that contains mainly cellulose, hemicellulose, and lignin. To improve the properties and functions of polymeric materials, cellulose is subjected to a variety of modifications. The most common modifications are surface modification, grafting, chemical procedures, and molecule chemical grafting. Injection molding and extrusion technologies are crucial in shaping and manufacturing polymer composites, with precise control over the process and material selection. Furthermore, injection molding involves four phases: plasticization, injection, cooling, and ejection, with a focus on energy efficiency. Fundamental aspects of an injection molding machine, such as the motor, hopper, heating units, nozzle, and clamping unit, are discussed. Extrusion technology, commonly used as a preliminary step to injection molding, presents challenges regarding fiber reinforcement and stress accumulation, while lignin-based polymeric materials are challenging due to their hydrophobicity. The diverse applications of these biodegradable materials include automotive industries, construction, food packaging, and various consumer goods. Polymeric materials are positioned to offer even bigger contributions to sustainable and eco-friendly solutions in the future, as research and development continues.

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This research aimed at evaluating optimal conditions to obtain value-added metabolites, such as bio-CH4, by co-digesting swine manure and food waste diluted in domestic sewage. The assays were carried out in batches using the statistical methods of Rotational Central Composite Design (RCCD) and Surface Response to evaluate the ranges of food waste (1.30-9.70 gTS.L-1), pH (6.16-7.84) and granular Upflow Anaerobic Sludge Blanket sludge as inoculum (2.32-5.68 gTS.L-1), besides about 250 mL of swine manure in 500 mL Duran flasks. According to the RCCD matrix, bio-CH4 yields among 600.6 ± 60.1 and 2790.0 ± 112.0 mL CH4 gTS.L-1 were observed, besides the maximum CH4 production rate between 0.4 ± 0.5 and 49.7 ± 2.0 mL CH4 h-1 and λ between ≤0.0 and 299.3 ± 4.5 h. In the validation assay, the optimal conditions of 9.98 gTS.L-1 of food waste, pH adjusted to 8.0 and 2.20 gTS.L-1 of inoculum were considered, and the bio-CH4 yield obtained (5640.79 ± 242.98 mL CH4 gTS.L-1 or also 5201.83 ± 224.07 mL CH4 gTVS.L-1) was 11.3 times higher than in assays before optimization (499.3 ± 16.0 mL CH4 gTS.L-1) with 5 gTS.L-1 of food waste, 3 gTS.L-1 of inoculum and pH 7.0. Besides, the results observed about the energetic balance of the control and validation assays highlight the importance of process optimization, as this condition was the only one with energy supply higher than the energy required for its operation, exceeding max consumption sevenfold. Based on the most dominant microorganisms (Methanosaeta, 31.06%) and the metabolic inference of the validation assay, it could be inferred that the acetoclastic methanogenesis was the predominant pathway to CH4 production.

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Endophytic fungi constitute a major part of the still unexplored fungal diversity and have gained interest as new biological sources of natural active compounds, including enzymes. Endophytic fungi were isolated from soybean leaves and initially screened on agar plates for the production of CMCase (carboxymethylcellulase), xylanase, amylase and protease. The highest Enzymatic Indexes (IE) were verified for xylanase (2.14 and 1.31) with the fungi M6-A6P5F2 and M12-A5P3F1.2 and CMCase (1.92 and 1.62) with the fungi M13-A9P2F1 and M12-A5P3F1.2, respectively. The production of xylanase and CMCase by the selected fungi was evaluated in submerged cultivation using beechwood xylan and carboxymethylcellulose (CMC), as well as sugarcane straw and bagasse in different ratios as carbon sources. Both types of lignocellulosic biomass proved to be good inducers of enzymatic activity. The best xylanase producer among the isolates was identified as Colletotrichum boninense. With this fungus, the highest xylanase activity was obtained with a sugarcane straw-bagasse mixture in a 50:50 ratio (383.63 U mL-1), a result superior to that obtained with the use of beechwood xylan (296.65 U mL-1). Regardingthe kinetic behavior of the crude xylanase, there was found optimal pH of 5.0 and optimal temperatures of 50°C and 60°C. At 40°C and 50°C, xylanase retained 87% and 76% of its initial catalytic activity, respectively. These results bring new perspectives on bioprospecting endophytic fungi for the production of enzymes, mainly xylanase, as well as the exploitation of agro-industrial by-products, such as sugarcane straw and bagasse.

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Xylooligosaccharides (XOS) are nondigestible compounds of great interest for food and pharmaceutical industries due to their beneficial prebiotic, antibacterial, antioxidant, and antitumor properties. The market size of XOS is increasing significantly, which makes its production from lignocellulosic biomass an interesting approach to the valorization of the hemicellulose fraction of biomass, which is currently underused. This review comprehensively discusses XOS production from lignocellulosic biomass, aiming at its application in integrated biorefineries. A bibliometric analysis is carried out highlighting the main players in the field. XOS production yields after different biomass pretreatment methods are critically discussed using Microsoft PowerBI® (2.92.706.0) software, which involves screening important trends for decision-making. Enzymatic hydrolysis and the major XOS purification strategies are also explored. Finally, the integration of XOS production into biorefineries, with special attention to economic and environmental aspects, is assessed, providing important information for the implementation of biorefineries containing XOS in their portfolio.

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Basidiomycetes are renowned as highly effective decomposers of plant materials, due to their extensive array of oxidative enzymes, which enable them to efficiently break down complex lignocellulosic biomass structures. Among the oxidative machinery of industrially relevant basidiomycetes, the role of lytic polysaccharide monooxygenases (LPMO) in lignocellulosic biomass deconstruction is highlighted. So far, only a limited number of basidiomycetes LPMOs have been identified and heterologously expressed. These LPMOs have presented activity on cellulose and hemicellulose, as well as participation in the deconstruction of lignin. Expanding on this, the current review proposes both enzymatic and non-enzymatic mechanisms of LPMOs for biomass conversion, considering the significance of the Carbohydrate-Binding Modules and other C-terminal regions domains associated with their structure, which is involved in the deconstruction of lignocellulosic biomass.

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Pullulan is an exopolysaccharide produced by Aureobasidium pullulans, with interesting characteristics which lead to its application in industries such as pharmaceuticals, cosmetics, food, and others. To reduce production costs for industrial applications, cheaper raw materials such as lignocellulosic biomass can be utilized as a carbon and nutrient source for the microbial process. In this study, a comprehensive and critical review was conducted, encompassing the pullulan production process and the key influential variables. The main properties of the biopolymer were presented, and different applications were discussed. Subsequently, the utilization of lignocellulosics for pullulan production within the framework of a biorefinery concept was explored, considering the main published works that deal with materials such as sugarcane bagasse, rice husk, corn straw, and corn cob. Next, the main challenges and future prospects in this research area were highlighted, indicating the key strategies to favor the industrial production of pullulan from lignocellulosic biomasses.

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In recent years, concerns about a good-quality diet have increased. Food supplements such as prebiotics have great nutritional and health benefits. Within the diverse range of prebiotics, xylooligosaccharides (XOs) show high potential, presenting exceptional properties for the prevention of systemic disorders. XOs can be found in different natural sources; however, their production is limited. Lignocellulosic biomasses present a high potential as a source of raw material for the production of XOs, making the agro-industrial by-products the perfect candidates for production on an industrial scale. However, these biomasses require the application of physicochemical pretreatments to obtain XOs. Different pretreatment methodologies are discussed in terms of increasing the production of XOs and limiting the coproduction of toxic compounds. The advance in new technologies for XOs production could decrease their real cost (USD 25-50/kg) on an industrial scale and would increase the volume of market transactions in the prebiotic sector (USD 4.5 billion). In this sense, new patents and innovations are being strategically developed to expand the use of XOs as daily prebiotics.

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A modification of the conventional batch organosolv process is proposed in a way where the solid biomass remains inside a basket, physically separated from the liquid phase, with the vapor promoting the fractionation of the biomass and the extracted compounds and fragments being washed down to the liquid phase. The modified organosolv process applied to sugarcane bagasse (SB-M) delivers a rich cellulosic solid phase that after enzymatic hydrolysis leads to a hydrolyzed with approximately 100 g L-1 of glucose. At the same enzymatic hydrolysis conditions, the conventional organosolv process (SB-C) delivers a hydrolyzed with 80 g L-1 of glucose, while the autohydrolysis process (SB-A) leads to 55 g L-1 of glucose. These different results are related to the cellulose content: SB-M (70%), SB-C (57%), e SB-A (44%), as well the reduced lignin content in the SB-M. The novelty of this study is the confirmation that it is possible to degrade lignin from sugarcane bagasse and simultaneously remove its fragments from the cellulose fibers in a batch reactor containing an internal basket. This study describes a simple and rapid protocol for the isolation of the main components of lignocellulosic biomass (cellulose, hemicellulose, and lignin), which may lead to the study of new catalysts for the chemical transformation of these components separately or simultaneously to the step of pretreatment.

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Lignocellulosic biomasses are used in several applications, such as energy production, materials, and biofuels. These applications result in increased consumption and waste generation of these materials. However, alternative uses are being developed to solve the problem of waste generated in the industry. Thus, research is carried out to ensure the use of these biomasses as enzymatic support. These surveys can be accompanied using the advanced bibliometric analysis tool that can help determine the biomasses used and other perspectives on the subject. With this, the present work aims to carry out an advanced bibliometric analysis approaching the main studies related to the use of lignocellulosic biomass as an enzymatic support. This study will be carried out by highlighting the main countries/regions that carry out productions, research areas that involve the theme, and future trends in these areas. It was observed that there is a cooperation between China, USA, and India, where China holds 28.07% of publications in this area, being the country with the greatest impact in the area. Finally, it is possible to define that the use of these new supports is a trend in the field of biotechnology.

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One of the critical steps of the biotechnological production of xylitol from lignocellulosic biomass is the deconstruction of the plant cell wall. This step is crucial to the bioprocess once the solubilization of xylose from hemicellulose is allowed, which can be easily converted to xylitol by pentose-assimilating yeasts in a microaerobic environment. However, lignocellulosic toxic compounds formed/released during plant cell wall pretreatment, such as aliphatic acids, furans, and phenolic compounds, inhibit xylitol production during fermentation, reducing the fermentative performance of yeasts and impairing the bioprocess productivity. Although the toxicity of lignocellulosic inhibitors is one of the biggest bottlenecks of the biotechnological production of xylitol, most of the studies focus on how much xylitol production is inhibited but not how and where cells are affected. Understanding this mechanism is important in order to develop strategies to overcome lignocellulosic inhibitor toxicity. In this mini-review, we addressed how these inhibitors affect both yeast physiology and metabolism and consequently xylose-to-xylitol bioconversion. In addition, this work also addresses about cellular adaptation, one of the most relevant strategies to overcome lignocellulosic inhibitors toxicity, once it allows the development of robust and tolerant strains, contributing to the improvement of the microbial performance against hemicellulosic hydrolysates toxicity. KEY POINTS: • Impact of lignocellulosic inhibitors on the xylitol production by yeasts • Physiological and metabolic alterations provoked by lignocellulosic inhibitors • Cell adaptation as an efficient strategy to improve yeast's robustness.

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This study is aimed at the analysis of the pyrolysis kinetics of Nanche stone BSC (Byrsonima crassifolia) as an agro-industrial waste using non-isothermal thermogravimetric experiments by determination of triplet kinetics; apparent activation energy, pre-exponential factor, and reaction model, as well as thermodynamic parameters to gather the required fundamental information for the design, construction, and operation of a pilot-scale reactor for the pyrolysis this lignocellulosic residue. Results indicate a biomass of low moisture and ash content and a high volatile matter content (≥70%), making BCS a potential candidate for obtaining various bioenergy products. Average apparent activation energies obtained from different methods (KAS, FWO and SK) were consistent in value (~123.8 kJ/mol). The pre-exponential factor from the Kissinger method ranged from 105 to 1014 min-1 for the highest pyrolytic activity stage, indicating a high-temperature reactive system. The thermodynamic parameters revealed a small difference between EA and ∆H (5.2 kJ/mol), which favors the pyrolysis reaction and indicates the feasibility of the energetic process. According to the analysis of the reaction models (master plot method), the pyrolytic degradation was dominated by a decreasing reaction order as a function of the degree of conversion. Moreover, BCS has a relatively high calorific value (14.9 MJ/kg) and a relatively low average apparent activation energy (122.7 kJ/mol) from the Starink method, which makes this biomass very suitable to be exploited for value-added energy production.

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ABSTRACTThis study evaluated the effectiveness of a semi-continuous flow-through subcritical water hydrolysis (SWH) pretreatment of brewer's spent grains (BSG) for subsequent application in the anaerobic digestion (AD) process. BSG pretreatment was conducted at 160 °C and 15 MPa with a flow rate of 10 mL water min-1 and 15 g water g-1 BSG. The results revealed that SWH attacked the hemicellulose structure, releasing arabinose (46.54 mg g-1) and xylose (39.90 mg g-1) sugars, and proteins (34.89 mg g-1). The start-up of anaerobic reactors using pretreated BSG (747.71 L CH4 kg-1 TVS) increased the methane yield compared with the reactor without pretreatment (53.21 L CH4 kg-1 TVS). For the process with pretreatment, the generation of electricity (134 kWh t-1 BSG) and heat (604 MJ t-1) are responsible for the mitigation of 43.90 kg CO2 eq t-1 BSG. The adoption of SWH as an eco-friendly pretreatment of biomass for AD could be a technological route to increase methane-rich biogas and bioenergy production, supporting the circular economy transition by reducing the carbon footprint of the beer industry.

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Lignocellulosic biomass (LCB) has remained a latent alternative resource to be the main substitute for oil and its derivatives in a biorefinery concept. However, its complex structure and the underdeveloped technologies for its large-scale processing keep it in a state of constant study trying to establish a consolidated process. In intensive processes, enzymes have been shown to be important molecules for the fractionation and conversion of LCB into biofuels and high-value-added molecules. However, operational challenges must be overcome before enzyme technology can be the main resource for obtaining second-generation sugars. The use of additives is shown to be a suitable strategy to improve the saccharification process. This review describes the mechanisms, roles, and effects of using additives, such as surfactants, biosurfactants, and non-catalytic proteins, separately and integrated into the enzymatic hydrolysis process of lignocellulosic biomass. In doing so, it provides a technical background in which operational biomass processing hurdles such as solids and enzymatic loadings, pretreatment burdens, and the unproductive adsorption phenomenon can be addressed.

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