Source Of Lignocellulosic Biomass Research Articles

Chemical approaches for the biomass valorisation: a comprehensive review of pretreatment strategies.

The most abundant natural renewable resource in the world, lignocellulosic biomass (LCB), has the potential to be exploited as a substitute green feedstock for the synthesis of various chemicals, materials, and biofuels. The annual global production of 13 billion tonnes of LCB offers an opportunity to cater to the increasing energy and materials requirement of process industries and also restricts the discharge of greenhouse gases. Although LCB is enriched with valuable ingredients such as cellulose, lignin, and hemicellulose, its recalcitrant nature limits its efficient utilisation. These components of LCB are strongly interlinked with each other, which resists their isolation and conversion valorisation into useful products. To disrupt the complicated structure of LCB and to isolate the lignocellulosic components in pure form, pretreatment is a crucial process in the bio-refinery, ensuring the economic feasibility of downstream processes. This review provides an outline of the structure, composition, and various sources of LCB; and the necessity of the pretreatment. Moreover, this article provides an in-depth analysis of the underlying mechanisms, advantages, and limitations of various pretreatment methods, such as physical, chemical, biological, and physicochemical. Further, the impact of chemical pretreatment techniques on the physicochemical characteristics of the material that is extracted from the biomass is also covered in detail through the rigorous evaluation of performance metrics, including substrate digestibility, sugar yield, inhibitor production, and energy requirements. This review provides a balanced and comprehensive overview of the state-of-the-art pretreatment strategies and their impact on biomass valorisation that will be useful to the scientists, engineers, and policy makers interested in biomass conversion technologies.

PINEPEAT from Pinus roxburghii (Chir Pine) foliage

Pinus roxburghii commonly known as Chir Pine is a coniferous tree native to the Himalayas. Pine needles shed from pine trees decay very slowly, form a carpet on the forest floor and are a major cause of frequent forest fires. The abundantly available unutilized pine needles are rich source of lignocellulosic biomass, goes waste, and its management through sustainable utilization has been a challenge.In the present study, pine needles were fibrillated by using laboratory disc refiner without any chemical treatment under different refiner passes from 0.10 to 0.40 mm to prepare pinepeat. The biomasses under different refiner passes were characterized for pH (6.2–6.5), freeness (481–821 ml), water absorbency (350–580 %), drainage time (9.10–16.99 sec), carbon (45.08 %), nitrogen (0.93 %), hydrogen (6.49 %), sulfur (0.13 %) content and C/N ratio (50.86 %). Anatomical characteristics of pine needle and pinepeat were also examined. The study reported significant change in morphology of pine needles after refining treatment wherein tissues turned into flattened, fibrillated and separated in short groups, increasing the surface area of the fragmented biomass. Application of processed pinepeat as amendments in nursery substrates was further assessed. The significantly higher growth parameters in pinepeat in comparison to conventional growing media suggests pinepeat as an additional environmentally sustainable choice for nursery operations in near future. The utility of pinepeat in this way is imperative for environment waste management and would turn into an alternative, renewable, and reliable growing media as amendments in nursery substrates.

Delignification of Different Lignocellulosic Biomass Using Hydrogen Peroxide and Acetic Acid (HPAC)

Lignocellulosic biomass will soon become the key source of feedstock for bioenergy to combat the impact of global warming and the depletion of fossil fuel resources. Lignin separation costs have been a key obstacle to bioenergy generation from lignocellulosic biomass. Pulp and paper, biofuel, and biomaterials sectors depend on wood delignification. This study examines delignification trends and advances, including standard and new methods. The study begins by explaining how delignification improves wood processability and value. It describes lignin's chemical structure and properties, highlighting its role in wood's mechanical and chemical qualities. Lignin from diverse lignocellulosic biomass sources is delignified using hydrogen peroxide and acetic acid in this study. A 1:1 hydrogen peroxide-acetic acid volume ratio was used after particle reduction. Experimental results show 96%, 89%, and 80% lignin removal efficiency for Ako, Mahogany, and mixed sawdust, respectively. A 30-minute reaction at 80°C yielded these results. The hydrogen peroxide-acetic acid mixture dignifies well and may be used in lignocellulosic biomass processing. This study also provides insights into optimizing delignification procedures and suggests approaches to improve the industrial use of lignocellulosic biomass. This study reveals that HPAC dignifies wood well. Understanding HPAC's role in the delignification of wood products could lead to developing an HPAC-based pretreatment technique that lowers the cost of biofuel generation from lignocellulosic biomass.

Enzymatic hydrolysis of cellulose banana stem (alkaline microwave-assisted pre-treatment)

The banana stem waste holds immense promise as a readily available and abundant source of lignocellulosic biomass, making it a compelling alternative for biofuel and biochemical applications. Therefore, this study focuses on investigating the impact of both time and substrate loading on the enzymatic hydrolysis of banana stem cellulose that has undergone alkaline microwave-assisted pre-treatment. The pre-treatment method involves subjecting the biomass to 5% KOH for 30 min, followed by microwave exposure at 300 W for 5 min, a process aimed at enhancing the accessibility of cellulose. Enzymatic hydrolysis experiments were carried out utilizing cellulase enzymes derived from Aspergillus niger, with variations in hydrolysis times (ranging from 5 to 45 h) and enzyme-to-substrate ratios (ranging from 1:1 to 1:10). The results of this investigation revealed a substantial improvement in hydrolysis efficiency, owing to the synergistic effects of alkaline microwave-assisted pre-treatment, signifying enhanced cellulose accessibility. Notably, the highest concentration of reducing sugars (1.3 mg mL−1) was achieved at a substrate-to-enzyme ratio of 1:1 and a hydrolysis duration of 45 h. These findings provide valuable insights into the conversion of lignocellulosic biomass, emphasizing the potential of integrated pre-treatment strategies for sustainable biorefinery applications. This research contributes to advancing our understanding of lignocellulosic biomass utilization, offering a promising avenue for biofuel and biochemical production from banana stem waste.

Efficient conversion of an underutilized low-lignin lignocellulosic biomass to cellulose nanocrystals and nanofibers via mild chemical-mechanical protocols

The production of high-quality nanocellulose (NC) from an underutilized low-lignin lignocellulosic biomass source, Phalaris aquatica L., was investigated via three conversion protocols. Initially, a conventional chemical protocol (Scenario I) was optimized using statistically designed experiments, and cellulose nanocrystals (CNCs) that exhibited an adequate crystallinity index (CI) were produced under mild conditions: short processing times, reduced temperatures and decreased use of chemicals and solvents. Hydrolysis temperature was found to contribute significantly to the variation of CI. Furthermore, two additional scenarios based on a planetary ball mill were comparatively applied, namely a combined chemical-mechanical (Scenario II) and an alternative (Scenario III) protocol, in which the ball milling step followed or replaced the acid hydrolysis step, respectively. In Scenarios II and III the NC structure was modified to cellulose nanofibrils (CNFs) and microfibrillated cellulose (MFC), respectively. Accordingly, the three different NC grades (CNCs, CNFs and MFC) were correlated with the three conversion protocols.

A detailed sensitivity analysis identifies the key factors influencing the enzymatic saccharification of lignocellulosic biomass

Corn stover is the most abundant form of crop residue that can serve as a source of lignocellulosic biomass in biorefinery approaches, for instance for the production of bioethanol. In such biorefinery processes, the constituent polysaccharide biopolymers are typically broken down into simple monomeric sugars by enzymatic saccharification, for further downstream fermentation into bioethanol. However, the recalcitrance of this material to enzymatic saccharification invokes the need for innovative pre-treatment methods to increase sugar conversion yield. Here, we focus on experimental glucose conversion time-courses for corn stover lignocellulose that has been pre-treated with different acid-catalysed processes and intensities. We identify the key parameters that determine enzymatic saccharification dynamics by performing a Sobol's sensitivity analysis on the comparison between the simulation results from our complex stochastic biophysical model, and the experimental data that we accurately reproduce. We find that the parameters relating to cellulose crystallinity and those associated with the cellobiohydrolase activity are predominantly driving the enzymatic saccharification dynamics. We confirm our computational results using mathematical calculations for a purely cellulosic substrate. On the one hand, having identified that only five parameters drastically influence the saccharification dynamics allows us to reduce the dimensionality of the parameter space (from nineteen to five parameters), which we expect will significantly speed up our fitting algorithm for comparison of experimental and simulated saccharification time-courses. On the other hand, these parameters directly highlight key targets for experimental endeavours in the optimisation of pre-treatment and saccharification conditions. Finally, this systematic and two-fold theoretical study, based on both mathematical and computational approaches, provides experimentalists with key insights that will support them in rationalising their complex experimental results.

Optimisation study of Ulmus pumila woody biomass fractionation by steam explosion for bioproducts production

Ulmus pumila represents a promising lignocellulosic biomass source for biofuels and bioproducts production since it can grow in low rainfall and extreme temperature zones. A first step in the conversion process is biomass fractionation to enhance the performance of the hydrolysis and subsequent biological conversion steps. The aim of this work is to optimise the main variables (temperature, residence time and the addition or not of sulphuric acid) of steam explosion to pretreat Ulmus pumila biomass. The optimal conditions to maximise both glucose and xylose recovery were 204.8 °C and 30 mg H2SO4/g biomass, obtained through a multilevel factorial design of experiments. Additionally, enzymatic hydrolysis using high solid loads (15% and 20% (w/w)) and different enzyme doses was studied. As a result, steam explosion at optimal conditions followed by enzymatic hydrolysis with 20% solid loading and 60 mg protein/g cellulose of enzyme allow the recovery of 70% of the potential sugars.

A systematic review of lignocellulosic biomass for remediation of environmental pollutants

Lignocellulosic wastes are the most promising feedstock, as they are the most inexpensive and abundantly renewable natural resource. The abundance of cellulose, lignin, and hemicellulose in feedstocks has been shown to be effective in eliminating persistent contaminants. Environmental issues, including the accumulation of agricultural waste, waste water treatment, and air pollution, could be resolved by producing value-added products like activated carbon from these wastes. Several biomass wastes were used to produce activated carbon using a two-step processing method that involved oxygen-free carbonisation and activation. This study examines the methods for making biochar from different lignocellulosic biomass sources. Furthermore, biochar modification significantly modifies surface area and pore volume. To determine the fundamental characteristics of biochar and to evaluate its potential for use in a variety of environmental applications, physical and chemical characterizations are required. Various widely used modern analytical techniques, such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), nuclear magnetic resonance spectroscopy (NMR), Brunauer-Emmett-Teller (BET), and Raman spectroscopy, have been reviewed in this work. The potential mechanisms through which lignocellulosic biochars may absorb pollutants are outlined. In general, this review highlights the significance and potential of activated carbon formed from waste products for environmental remediation, demonstrating that biomass-originated activated carbon could have a significant impact on increasing economic viability and efficiently protecting the environment.

An Overview of Lignocellulose and Its Biotechnological Importance in High-Value Product Production

Lignocellulose consists of cellulose, hemicellulose, and lignin and is a sustainable feedstock for a biorefinery to generate marketable biomaterials like biofuels and platform chemicals. Enormous tons of lignocellulose are obtained from agricultural waste, but a few tons are utilized due to a lack of awareness of the biotechnological importance of lignocellulose. Underutilizing lignocellulose could also be linked to the incomplete use of cellulose and hemicellulose in biotransformation into new products. Utilizing lignocellulose in producing value-added products alleviates agricultural waste disposal management challenges. It also reduces the emission of toxic substances into the environment, which promotes a sustainable development goal and contributes to circular economy development and economic growth. This review broadly focused on lignocellulose in the production of high-value products. The aspects that were discussed included: (i) sources of lignocellulosic biomass; (ii) conversion of lignocellulosic biomass into value-added products; and (iii) various bio-based products obtained from lignocellulose. Additionally, several challenges in upcycling lignocellulose and alleviation strategies were discussed. This review also suggested prospects using lignocellulose to replace polystyrene packaging with lignin-based packaging products, the production of crafts and interior decorations using lignin, nanolignin in producing environmental biosensors and biomimetic sensors, and processing cellulose and hemicellulose with the addition of nutritional supplements to meet dietary requirements in animal feeding.

A review of nanocellulose modification and compatibility barrier for various applications

Nanocellulose is increasingly important due to its abundance and sustainability sources, outstanding physicochemical properties, low density, high specific surface area, and easily modified surface chemistry. Nanocellulose is obtained from various sources, such as plants, algae, and bacteria, with plant-derived nanocellulose being the most common. Their presence significantly benefits many applications, especially in developing advanced materials for high end-use. Despite these benefits, the intrinsic hydrophilic behavior complicates dispersion in hydrophobic polymer matrices due to aggregation issues that result in deterioration properties. Nanocellulose modification and surface tuning are identified as fundamental approaches for improving the compatibility of the interfacial interaction between nanocellulose and polymer matrix to impart new functionalities to novel advanced materials. This article offers insight into nanocellulose by highlighting various lignocellulosic biomass sources and their chemical constituents. Three categories of nanocellulose are discussed in this review, including cellulose nanocrystals, cellulose nanofibrils, and bacterial nanocellulose. This article also featured several methods for promoting surface modification of nanocellulose to overcome the compatibility barrier between nanocellulose and polymer matrix to achieve a balanced hydrophilic-hydrophobic behavior. A few recent and emerging applications of nanocellulose-based composites are also presented in this review.

Isolation of nanocellulose from Dodonaea viscosa plant: structural and thermal properties

Abstract In this research work, cellulose was isolated from Dodonaea viscosa plant by means of various chemical processes followed by the preparation of nanocellulose through sulfuric acid hydrolysis. These chemical processes begin with the removal of non-cellulosic material such as lignin, pectin, crude wax, and hemicellulose followed by alkaline treatment and chlorine-free bleaching methods. Fourier transform infrared (FTIR) spectroscopy showed the successful isolation of cellulosic material after removing hemicellulose, lignin, and other extractives. Thermogravimetric analysis (TGA) elucidated the thermal degradation profile of the cellulose-based materials obtained after various chemical procedures at each step. Additionally, nanocellulose was prepared from cellulosic material using acid hydrolysis, and its structural and thermal properties were discussed. Nanocellulose extraction from the lignocellulosic biomass sources and its further utilization has been the subject of intensive research as the global community needs the use of green chemistry principles in recent life. Nanocellulosic material due to its unique characteristics and properties is of great importance and has many applications in various industries, including materials science and engineering.

Optimization of hydrothermal-assisted alkali process for enhanced xylan recovery from banana fiber biomass

Banana fiber is a rich lignocellulosic biomass source that has not been widely explored. The hemicellulose components (15 - 20 %) of banana fiber can be a feedstock for producing high-value commodity chemicals. Hemicellulose is extracted by physical, chemical, and biological methods, in which combining hydrothermal treatment with alkaline mode of extraction provides an enhanced recovery percentage. Thus, the present study aimed to optimize the hydrothermal-assisted alkaline method of xylan extraction from the banana fiber biomass. Initially, xylan was extracted with a conventional-based alkali method. A maximum of about 43 and 35 % was recovered from pretreated and raw banana fiber at 12% NaOH concentration when incubated at 55 °C for 24 h. To improve the xylan yield, the hydrothermal assisted alkali method experimented in which 67.1% and 58.3 % of xylan were recovered when treated at 121 °C for 1 h at 12% NaOH. To further enhance the xylan recovery, a two-step alkali process by combining conventional and hydrothermal-assisted alkali methods resulted in the highest xylan (81%) recovery from pretreated banana fiber when incubated with 12 % alkali for 8 h followed by steam treatment. On the other hand, a maximum of 73 % of xylan was recovered when steam treated after incubation for 24 h from raw banana fiber. Thus, the alkali incubation followed by steam treatment significantly showed the highest xylan recovery from the banana fiber biomass. The extracted xylan might be utilized as a source for various xylan-based products, including furfural, xylooligosaccharides, xylose, and xylitol, all of which have significant roles in the pharmaceutical and food industries.

Sustainable biohydrogen production from lignocellulosic biomass sources - metabolic pathways, production enhancement, and challenges.

Hydrogen production from biological processes has been hailed as a promising strategy for generating sustainable energy. Fermentative hydrogen production processes such as dark and photofermentation are considered more sustainable and economical than other biological methods such as biophotolysis. However, these methods have constraints such as low hydrogen yield and conversion efficiency, so practical implementations still need to be made. The present review provides an assessment and feasibility of producing biohydrogen through dark and photofermentation techniques utilizing various lignocellulosic biomass wastes as substrates. Furthermore, this review includes information about the strategies to increase the productivity rate of biohydrogen in an eco-friendly and sustainable manner, like integration of dark and photofermentation techniques, pretreatment of biomass, genetic modification of microorganisms, and application of nanoadditives.

Evaluation of biotechnological processing through solid-state fermentation of oilseed cakes on extracts bioactive potential

Oilseed cakes (OC) are natural sources of lignocellulosic biomass, produced every year in large amounts. In addition to their main applications as animal feed, plant or soil fertilizer, and compost, they present enormous potential for being used in biotechnological processes for the obtainment and extraction of valuable bioactive compounds. This work evaluated the effect of solid-state fermentation on the bioactive properties of extracts obtained from the bioprocessing of OC and evaluated the effect of solvents on the recovery of compounds with higher bioactive potential. A general decrease of EC50 values was observed for fermented extracts obtained using a mixture of water/methanol (1:1) as extraction solvent. A decrease in the minimum inhibitory concentration was observed for fermented water extracts compared to non-fermented. Additionally, growth inhibition of Listeria monocytogenes was observed when using aqueous methanolic fermented extracts. These extracts also exhibited a higher percentage of growth reduction against phytopathogenic fungi, and some extracts exhibited increased protection against genotoxic agents such as camptothecin and bisphenol A. It was demonstrated that bioprocessing of OC through SSF is an effective approach to obtaining valuable compounds with bioactive properties for use in the food, pharmaceutical or cosmetic industries.

Hydrogen-Transfer Reductive Catalytic Fractionation of Lignocellulose: High Monomeric Yield with Switchable Selectivity.

Lignin solubilization and in situ hydrogenolysis are crucial for reductive catalytic fractionation (RCF) of lignocellulose to aromatic monomers. In this study, we reported a typical hydrogen bond acceptor of choline chloride (ChCl) to tailor the hydrogen-donating environment of the Ru/C-catalyzed hydrogen-transfer RCF of lignocellulose. The ChCl-tailored hydrogen-transfer RCF of lignocellulose was conducted under mild temperature and low-pressure (<1 bar) conditions, which was applicable to other lignocellulosic biomass sources. We obtained an approximate theoretical yield of propylphenol monomer of 59.2 wt % and selectivity of 97.3 % using an optimal content of ChCl (10 wt %) in ethylene glycol at 190 °C for 8 h. When the content of ChCl in ethylene glycol was increased to 110 wt %, the selectivity of propylphenol switched toward propylenephenol (yield of 36.2 wt % and selectivity of 87.6 %). The findings in this work provide valuable information for transforming lignin from lignocellulose into value-added products.

Hydrogen‐Transfer Reductive Catalytic Fractionation of Lignocellulose: High Monomeric Yield with Switchable Selectivity

AbstractLignin solubilization and in situ hydrogenolysis are crucial for reductive catalytic fractionation (RCF) of lignocellulose to aromatic monomers. In this study, we reported a typical hydrogen bond acceptor of choline chloride (ChCl) to tailor the hydrogen‐donating environment of the Ru/C‐catalyzed hydrogen‐transfer RCF of lignocellulose. The ChCl‐tailored hydrogen‐transfer RCF of lignocellulose was conducted under mild temperature and low‐pressure (&lt;1 bar) conditions, which was applicable to other lignocellulosic biomass sources. We obtained an approximate theoretical yield of propylphenol monomer of 59.2 wt % and selectivity of 97.3 % using an optimal content of ChCl (10 wt %) in ethylene glycol at 190 °C for 8 h. When the content of ChCl in ethylene glycol was increased to 110 wt %, the selectivity of propylphenol switched toward propylenephenol (yield of 36.2 wt % and selectivity of 87.6 %). The findings in this work provide valuable information for transforming lignin from lignocellulose into value‐added products.

Mechanism of Zn2+ regulation of cellulase production in Trichoderma reesei Rut-C30

BackgroundTrichoderma reesei Rut-C30 is a hypercellulolytic mutant strain that degrades abundant sources of lignocellulosic plant biomass, yielding renewable biofuels. Although Zn2+ is an activator of enzymes in almost all organisms, its effects on cellulase activity in T. reesei have yet to be reported.ResultsAlthough high concentrations of Zn2+ severely suppressed the extension of T. reesei mycelia, the application of 1–4 mM Zn2+ enhanced cellulase and xylanase production in the high-yielding cellulase-producing Rut-C30 strain of T. reesei. Expression of the major cellulase, xylanase, and two essential transcription activator genes (xyr1 and ace3) increased in response to Zn2+ stimulation. Transcriptome analysis revealed that the mRNA levels of plc-e encoding phospholipase C, which is involved in the calcium signaling pathway, were enhanced by Zn2+ application. The disruption of plc-e abolished the cellulase-positive influence of Zn2+ in the early phase of induction, indicating that plc-e is involved in Zn2+-induced cellulase production. Furthermore, treatment with LaCl3 (a plasma membrane Ca2+ channel blocker) and deletion of crz1 (calcineurin-responsive zinc finger transcription factor 1) indicated that calcium signaling is partially involved in this process. Moreover, we identified the zinc-responsive transcription factor zafA, the transcriptional levels of which declined in response to Zn2+ stress. Deletion of zafA indicates that this factor plays a prominent role in mediating the Zn2+-induced excessive production of cellulase.ConclusionsFor the first time, we have demonstrated that Zn2+ is toxic to T. reesei, although promotes a marked increase in cellulase production. This positive influence of Zn2+ is facilitated by the plc-e gene and zafA transcription factor. These findings provide insights into the role of Zn2+ in T. reesei and the mechanisms underlying signal transduction in cellulase synthesis.

Challenges in Syngas Fermentation for Bioethanol Production: Syngas Composition

Energy challenges in developing countries are more significant if they continue to use fossil materials and have an impact on air quality. Lignocellulosic biomass can be an alternative to new renewable sources to replace fossil materials. Indonesia produces various sources of lignocellulosic biomass, which can be used in multiple energy sources such as bioethanol. The hybrid pathway is one of the routes for producing bioethanol. The first stage of the hybrid process is the conversion of biomass into CO, CO2, and H2 (syngas) gas through the gasification process. Then the syngas is converted into bioethanol through fermentation using microorganisms as biocatalysts. The bioethanol production line is the Wood-Ljungdahlii pathway. Factors that affect syngas are the type of biomass (chemical, physical, and morphological properties) and the gasification process (type of gasifier, temperature, gasification agent, and ratio equilibrium (ER)). This paper reviews the challenges in implementing syngas fermentation. In particular, variations in the composition of syngas as a substrate for fermentation.

From trash to treasure: Sourcing high-value, sustainable cellulosic materials from living bioreactor waste streams

The appreciation of how conventional and fossil-based materials could be harmful to our planet is growing, especially when considering single-use and non-biodegradable plastics manufactured from fossil fuels. Accordingly, tackling climate change and plastic waste pollution entails a more responsible approach to sourcing raw materials and the adoption of less destructive end-of-life pathways. Livestock animals, in particular ruminants, process plant matter using a suite of mechanical, chemical and biological mechanisms through the act of digestion. The manure from these “living bioreactors” is ubiquitous and offers a largely untapped source of lignocellulosic biomass for the development of bio-based and biodegradable materials. In this review, we assess recent studies made into manure-based cellulose materials in terms of their material characteristics and implications for sustainability. Despite the surprisingly diverse body of research, it is apparent that progress towards the commercialisation of manure-derived cellulose materials is hindered by a lack of truly sustainable options and robust data to assess the performance against conventional materials alternatives. Nanocellulose, a natural biopolymer, has been successfully produced by living bioreactors and is presented as a candidate for future developments. Life cycle assessments from non-wood sources are however minimal, but there are some initial indications that manure-derived nanocellulose would offer environmental benefits over traditional wood-derived sources.

High-pressure microwave-assisted pretreatment of softwood, hardwood and non-wood biomass using different solvents in the production of cellulosic ethanol

BackgroundPretreatment is an indispensable stage of the preparation of lignocellulosic biomass with key significance for the effectiveness of hydrolysis and the efficiency of the production of cellulosic ethanol. A significant increase in the susceptibility of the raw material to further degradation can be attained as a result of effective delignification in high-pressure conditions. With this in mind, a method of high-pressure pretreatment using microwave radiation and various solvents (water, 40% w/v NaCS, 1% v/v H2SO4, 1% w/v NaOH or 60% v/v EtOH with an addition of 1% v/v H2SO4) was developed, enabling the acquisition of biomass with an increased susceptibility to the process of enzymatic hydrolysis. The medium obtained in this way can be used for the production of cellulosic ethanol via high-gravity technology (lignocellulosic media containing from 15 to 20% dry weight of biomass). For every type of biomass (pine chips, beech chips and wheat straw), a solvent was selected to be used during the pretreatment, guaranteeing the acquisition of a medium highly susceptible to the process of enzymatic hydrolysis.ResultsThe highest efficiency of the hydrolysis of biomass, amounting to 71.14 ± 0.97% (glucose concentration 109.26 ± 3.49 g/L) was achieved for wheat straw subjected to microwave-assisted pretreatment using 40% w/v NaCS. Fermentation of this medium produced ethanol concentration at the level of 53.84 ± 1.25 g/L. A slightly lower effectiveness of enzymatic hydrolysis (62.21 ± 0.62%) was achieved after high-pressure microwave-assisted pretreatment of beech chips using 1% w/v NaOH. The hydrolysate contained glucose in the concentration of 91.78 ± 1.91 g/L, and the acquired concentration of ethanol after fermentation amounted to 49.07 ± 2.06 g/L. In the case of pine chips, the most effective delignification was achieved using 60% v/v EtOH with the addition of 1% v/v H2SO4, but after enzymatic hydrolysis, the concentration of glucose in hydrolysate was lower than in the other raw materials and amounted to 39.15 ± 1.62 g/L (the concentration of ethanol after fermentation was ca. 19.67 ± 0.98 g/L). The presence of xylose and galactose was also determined in the obtained fermentation media. The highest initial concentration of these carbohydrates (21.39 ± 1.44 g/L) was observed in beech chips media after microwave-assisted pretreatment using NaOH. The use of wheat straw after pretreatment using EtOH with an addition of 1% v/v H2SO4 for the preparation of fermentation medium, results in the generation of the initial concentration of galactose and xylose at the level of 19.03 ± 0.38 g/L.ConclusionThe achieved results indicate a high effectiveness of the enzymatic hydrolysis of the biomass subjected to high-pressure microwave-assisted pretreatment. The final effect depends on the combined use of correctly selected solvents for the different sources of lignocellulosic biomass. On the basis of the achieved results, we can say that the presented method indicates a very high potential in the area of its use for the production of cellulosic ethanol involving high-gravity technology.