Lignocellulosic Waste Research Articles

A Comparative Study of Various Substrate Combinations on Mass Multiplication of Trichoderma lexii (T-94a)

The high cost of raw materials has long hindered the large-scale commercialization of Trichoderma sp. conidiophore formulations. This study addresses the need for affordable, nutrient-rich alternatives by exploring the use of lignocellulosic residues, comprising lignin, cellulose, and hemicellulose, as a carbon source for cultivating Trichoderma. These fungi possess unique attributes, such as filamentous growth and prolific spore production, which make them valuable for composting lignocellulosic waste. Using different substrates with a combination of straws effectively helps in the decomposition of straw and enhances the mass multiplication of Trichoderma lexii (T-94a). Different substrates such as broken rice, grounded maize, gram flour, sorghum & broken wheat were used in combination with paddy straws. A combination of Maize + straw induced an early response in the mycelial growth of Trichoderma lexii (T-94a). After 5 and 10 days of inoculation, physical parameters such as growth and sporulation characteristics of T. lexii (T-94a) show highly uniform growth and profuse sporulation on maize and straw combination as compared to broken rice & straw, sorghum, and straw combinations. This finding has promising implications for improving agricultural practices and waste management. Further research can fine-tune the optimal substrate ratios to enhance the efficiency of biocontrol agents and waste decomposition. Scaling up the application of these substrate combinations in real-world farming scenarios and assessing their long-term environmental impact will be essential for realizing the full potential of these sustainable agricultural practices.

Agro-wastes bioconvertion by an Amazonian isolate of Ganoderma sp. and a commercial strain of Ganoderma lingzhi

Agro-industrial wastes discarded in nature may cause environmental damage; however, they have potential for application in mushroom cultivation, making it possible to bioconvert these wastes into materials of higher added value with the possibility of application in different industrial segments. The aim of this work was to compare the biotransformation potential of Amazon lignocellulosic wastes by Ganoderma sp. (isolated in the Amazon) and G. lingzhi (a commercial strain). The mushrooms were grown in açaí (Euterpe sp.), guaruba-cedro (Vochysia maxima), and three different batches of marupá (Simarouba amara) wastes. Initial substrates (IS) and spent mushroom substrates (SMS) were subjected to physico-chemical analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), and crystallinity index (CrI). A trend to decrease moisture, ash, lipids, carbon, and cellulose levels was observed in SMS. It is highlighted that after the growth of G. lingzhi and Ganoderma sp., there was a reduction in lignin by 29% and 48%, respectively, while there was an average increase in nitrogen content of 44% and 142% in SMS, respectively. SEM analysis showed visible loosening of lignocellulose fibers; XRD showed a characteristic peak of amorphous cellulose; and the CrI highlighted the coexistence of ordered and disordered regions. Thus, the mushrooms have shown potential in the bioconversion of Amazon wastes, notably for Ganoderma sp., which has demonstrated high potential for delignification and fortification of waste playing potential for application in the cellulose and animal feed industries.

Impact of antibiotics on methane produced from cellulose

Enhancing production of methane from cellulose is of utmost importance to improve the fermentation efficiency of lignocellulosic biomass. Antibiotics have demonstrated their ability to stimulate anaerobic digestion (AD) by influencing micro-organism activity. However, there has been limited research on the specific effect of antibiotics on cellulose AD. In this study, we investigated the impact of three antibiotics—tetracycline (TC), cephalexin (CLX), and azithromycin (AZM)—on cellulose AD when inoculated with waste sewage sludge. The results revealed that the presence of AZM and TC led to significantly higher methane yields, with increases of 51.94% and 34.96%, respectively, during a 20-day AD period. In contrast, the presence of CLX resulted in a 23.95% lower methane yield compared to the control. Furthermore, detailed analyses indicated that AZM had a positive influence on cellulose AD at all stages, including methanogenesis, acidogenesis/acetogenesis, and hydrolysis. On the other hand, TC primarily promoted AD during the methanogenesis stage. These findings collectively offer valuable guidance for efficiently transforming the energy potential of lignocellulosic wastes.

Harnessing Artificial Neural Networks and large language models for bioprocess optimization: Predicting sugar output from Kraft waste-based lignocellulosic pretreatments

This study implements Artificial Neural Network (ANN) models as predictive tools for glucose responses from Kraft waste-based pretreatments. The developed steam- and microwave-assisted ANN models achieved R2 scores > 0.95 for the observed and predicted glucose responses. An in-depth sensitivity analysis revealed that the glucose responses for the steam and microwave models were highly susceptible to the stepwise variation in green liquor dregs concentration (>3.3-fold) and power intensity (>2.6-fold), respectively. Comparative assessment on the capability of the large language model, ChatGPT, to generate innovative and factually accurate insights based on the process data was carried out. The novel process insights deduced by ChatGPT concurred with the authors’ findings of this study, underscoring the unique critical role of integrating advanced artificial intelligence and domain-specific knowledge to accelerate progression in lignocellulosic waste pretreatment. As such, these synergies align with global sustainable developmental objectives that leverage 4IR technologies, propelling this research field forward.

Machine learning-based prediction of methane production from lignocellulosic wastes

The biochemical methane potential test is a standard method to determine the biodegradability of lignocellulosic wastes (LWs) during anaerobic digestion (AD) with disadvantages of long experiment duration and high operating expense. This paper developed a machine learning model to predict the cumulative methane yield (CMY) using the data of 157 LWs regarding physicochemical characteristics, digestion condition and methane yield, with the coefficient of determination equal to 0.869. Model interpretability analyses underscored lignin content, organic loading, and nitrogen content as pivotal attributes for CMY prediction. For the feedstocks with a cellulose content exceeding about 50%, the CMY in the early AD stage would be relatively lower than those with low cellulose content, but prolonging digestion time could promote methane production. Besides, lignin content in feedstock surpassing 15% would significantly inhibit methane production. This work contributes to valuable guidance for feedstock selection and operation optimization for AD plants.

The Implementation of Waste Biomass Substrates as Feedstock for The Production of Bio-Electricity Through Microbial Fuel Cells (MFCS): A Short Review

Lignocellulosic biomass plays a pivotal role in sustainable energy production, with a focus on indirect biomass fuel cells (IDBFC) and direct biomass fuel cells (DBFC). IDBFCs require the initial conversion of biomass into simpler forms like sugars, biogas, syngas, or biocharfor subsequent electricity generation. In contrast, DBFCs offer a more direct approach, generating electricity from biomass without intermediate steps. Lignocellulosic biomass, composed of cellulose, lignin, and hemicellulose, has diverse applications, from bioethanolto direct electricity generation. However, the complex composition of lignocellulosic compounds, including carbon, hydrogen, oxygen, phosphorus, nitrogen, and sulfur, poses challenges for efficient enzymatic hydrolysis, a crucial factor in achieving high power density inMicrobial Fuel Cells (MFCs). MFCs use microorganisms to convert substrates into electricity, influenced by factors like substrate degradation rate, circuit resistance, electron transfer rates, proton mass transfer, electrode materials, and operational conditions. The selection of proper electrode materials is vital for optimising MFC performance. At the heart of MFC performance are electricigens, microorganisms facilitating electron transfer from biomass to the anode through direct or indirect mechanisms. Direct electron transfer (DET), relying on physical contact between microorganism membranes and the anode, is preferred for its efficiency and eco-friendliness. The paper also explores the importance of nutrient supplements (macro and micro) in enhancing bio-methane production and process stability in agro-industrial biogas mono-digestion plants. Nutrient balance significantly affects microbial generation time, degradation rates, and gas production in anaerobic digestion processes. In conclusion, understanding the intricate interplay between lignocellulosic biomass energy fuel cells, electricigens, and their performance factors is crucial for advancing sustainable energy production. MFCs show promise in utilising sludge and various waste biomasses, positioning them as practical, reliable, and versatile power sources in the evolving landscape of renewable energy technologies.
 Keywords: Lignocellulosic waste, bioenergy, microbial fuel cells (MFCs), electricigens

Gasification of Coffee Parchment as Potential Method for Coffee Agro-Industry Waste Utilization

Coffee parchment is a lignocellulosic waste material which has a potential to transform into synthesis gas. This research aims to study the feasibility of coffee parchment conversion under downdraft gasification with ‘auto-heating’ supply method. The temperature profile in each zone of the reactor was investigated as the effect of different equivalence ratio (ER) as well as the producer gas characteristics such as ignition time, flame duration, colour and temperature, carbon conversion and producer gas composition. Initially, coffee parchment collected from dehulling process was sun-dried three to four days. The gasification was ignited by firing ca. 300 g of wood charcoal inside the reactor before the coffee parchment loaded, then the reactor was tighly closed. Once the combustible gas was produced, the gasification time was measured. The result shows that the highest operational temperature inside the reactor was 715.66 °C within the combustion zone. The biomass conversion tends to increase by the increasing of ER, but the producer gas might dilute by more carbon dioxide production, and nitrogen input into the producer gas which indicated by the flame duration, colour, and temperature. Introducing an ER of 0.3 into the gasification reactor has provided adequate amount of oxygen to convert the coffee parchment into producer gas. This investigation suggests that coffee parchment is feasible to be converted into syngas. However, providing an advance process integrated to cleaning system would be required in the future to obtain a fuel grade syngas.

Modified Lignocellulosic Waste for the Amelioration of Water Quality: Adsorptive Removal of Congo Red and Nitrate Using Modified Poplar Sawdust

Since the synthetic dye Congo red and nitrate are notorious contributors to water pollution due to their persistent and potentially toxic nature, it is necessary to develop new efficient methods to remove them from water bodies. Native lignocellulosic materials as biosorbents are mostly inferior, i.e., the adsorption capacities of native materials are lower. Therefore, attempts have been made to improve the adsorption capacities of such materials by physical and/or chemical methods, including the production of biochar. In this study, adsorptive removal was investigated using a novel biosorbent (mPWS) obtained by modifying poplar (waste) sawdust through quaternisation. The characterisation of mPWS included SEM/EDX, FTIR, and MIP analysis. The adsorption of CR and nitrate onto mPWS was studied in a batch system, as a function of contact time (1–240 min), biosorbent concentration (1–8 g·dm−3), and initial adsorbate concentration (25–200 mg·dm−3). In all experiments, a high removal of both adsorbates, from 60 to over 90%, was achieved. Langmuir and Freundlich adsorption isotherm models were used in order to describe equilibrium adsorption data, while pseudo-first-order and pseudo-second-order kinetic models, and the intraparticle diffusion model, were used to describe possible adsorption mechanisms. The Langmuir model fit the adsorption data of CR well, while the nitrate adsorption process was better interpreted with the Freundlich isotherm model. The kinetics data for both CR and nitrate agreed with the pseudo-second-order kinetics model, while analysis using the intraparticle diffusion model indicated two rate-limiting steps during the adsorption process. Based on the results, it can be concluded that the tested novel biosorbent can be effectively used for the removal of CR and nitrate from water (with its adsorption capacities being 70.3 mg·g−1 and 43.6 mg·g−1, respectively).

Immobilization performance of graphene oxide-based engineered biochar derived from peanut shell towards cationic and anionic dyes

Water pollution due to variety of organic contaminants is a serious global threat due to its adverse effects on aquatic life, terrestrial organisms and environment. In this sense, sustainable wastewater treatment using materials derived from lignocellulosic wastes has received considerable scientific attention because they are abundant, low-cost and functional-group rich. In this work, a facile approach has been demonstrated to design peanut shell biochar-graphene oxide (PBC@GO)-based binary composite. Herein, PBC@GO composite was fabricated and assessed as an adsorptive platform for cationic and anionic dyes viz. Crystal Violet (CV) and Bromophenol Blue (BPB), respectively, as model pollutants. The test materials were characterized by means of SEM, FTIR, XRD and TGA. The influence of pH, time, dosage and concentration of model pollutants was ascertained for optimal performance in batch mode. Results showed that PBC@GO efficiently removed CV (97 %) and BPB (87 %), whilst kinetic data accorded well with pseudo-second-order model with R2 values of 0.97 and 0.99 for CV and BPB, respectively. Moreover, equilibrium data was fitted to the Langmuir and Freundlich models to understand sorption mechanism for CV and BPB dyes. Comparative study showed synergistic effects of PBC and GO in terms of better removal efficiency due to the availability of multi-interaction sites in PBC@GO composite as compared to the precursors. Apart from superior pollutant's uptake ability, high % recoveries obtained by using spiked real water samples as well as long term stability of the prepared composite when subjected to five successive cycle of use without any substantial loss of its ability towards scavenging dyes were crucial for improving sustainability of water treatment systems.

Rice Straw Waste-Based Biogas Production via Microbial Digestion: A Review.

The development of sustainable and renewable energy production is in high demand, and bioenergy production via microbial digestion of organic wastes is in prime focus. Biogas produced from the microbial digestion of organic waste is the most promising among existing biofuel options. In this context, biogas production from lignocellulosic biomass is one of the most viable and promising technologies for sustainable biofuel production. In the present review, an assessment and feasibility advancement have been presented towards the sustainable production of biogas from rice straw waste. Rice straw (RS) is abundantly available, contains a high composition of cellulose, and is found under the category of lignocellulosic waste, but it may cause severe environmental issues if not treated. Whereas, due to its high cellulose and inorganic content, lower cost, and huge availability, this waste can be effectively valorized into biogas production at a lower cost on a commercial scale. Therefore, the present review provides existing insight in this area by focusing on the operational parameter's improvement and advancement in the research for the expansion of mass-scale production at a lower cost. Thus, the presented review analyzed the processing parameters status, associated challenges, and positive endnote solutions for more sustainable viability for biogas production.

Harnessing lignocellulosic biomass for butanol production through clostridia for sustainable waste management: recent advances and perspectives

The escalating waste generation rates, driven by population growth, urbanization, and consumption patterns, have made waste management a critical global concern with significant environmental, social, and economic repercussions. Among the various waste sources, lignocellulosic biomass represents a significant proportion of agricultural, agro-industrial, and municipal wastes. Biofuels are gaining attention as a promising substitute to fossil fuels, and butanol is one such biofuel that has been identified as a potential candidate due to its compatibility with existing fuel infrastructure, lower volatility, and higher energy density. Sustainable management of lignocellulosic biomass waste and its utilization in fermentation are viable alternatives to produce butanol via the promising microbial catalyst clostridia. This review provides an overview of lignocellulosic biomass waste management, focusing on recent advances in strain development for butanol production from renewable biomass with an emphasis on future perspectives.

Development of a composite based on polylactic acid and lignocellulosic waste: new packaging for meat food storage

Pursuing new packaging that contributes to the safety of meat products, that can also be from renewable sources and that has adequate mechanical properties is a challenge. Therefore, this study attempted to incorporate a layer of polylactic acid (PLA) containing nisin and oregano oil extract (OEO) into biocomposites of cassava bran (CB) and coffee husk (CH) to improve their mechanical properties and enhance their antimicrobial properties. A compression molding process is carried out, the operating conditions for the preparation of the biocomposite were pressure: 40 bar, temperature: 170°C, and time: 2.5 min. The composition of the biocomposite was 80, 18, and 2% of CB, CH, and glycerol respectively, with 30% moisture. The polylactic acid (PLA) layer was added by immersion and contained nisaplin and OEO. PLA layer was evaporated in forced convection oven. Once the active packaging was obtained, inhibition in vitro against Listeria monocytogenes was performed. The packing containing OEO and nisin that showed the highest inhibition on the pathogen was used for stability analysis in pork. In order to measure changes in pork meat quality, the biocomposite with and without coating and with commercial polystyrene packaging were compared. Raw meat muscle was kept at 4° C and was tested for color, pH, moisture, and texture profile analysis (TPA) for 0, 7, 14, and 21 days. The values of the flexural test of the biocomposite were: 11.08 MPa of maximum flexural strength (σF), 1.81% of maximum deformation (εF), and 842.22 MPa of elastic modulus (EM). According to the results of in vitro inhibition, the packaging can contribute to reduce the proliferation of gram-positive microorganisms, such as L. monocytogenes. During storage, the hardness and gumminess of the meat showed significant changes, mainly in the PLA-free biocomposite. Results on pork meat showed that packaging with antimicrobials and PLA can maintain color, texture, moisture, and pH similar to commercial packaging.

Enhancing biochar properties through doping: A comparative study of sugarcane bagasse and chicken feather

This comparative study explores the production and characterization of biochar derived from a combination of sugarcane bagasse (SB) and chicken feathers (CF), with a doping strategy for each biomass in the other. Two biochars, SB92CF-BC (92% SB and 8% CF) and CF92SB-BC (92% CF and 8% SB), were produced using a top-lit updraft reactor, resulting in a yield of 34% and 27%, respectively. Fourier transform infrared spectroscopy (FTIR) analysis revealed characteristic functional groups in both biochars, with minimal impact from the doping process. Scanning electron spectroscopy (SEM) analysis showed distinct morphological features, with SB92CF-BC exhibiting a smoother surface and CF92SB-BC displaying an irregular and rough morphology. Energy dispersive X-ray spectroscopy (EDS) analysis confirmed the presence of several elements in both biochars, with a higher nitrogen content in CF92SB-BC. Brunauer-Emmett-Teller (BET) analysis demonstrated significant specific surface areas for both biochars, exceeding those reported for unmodified SB and CF biochars. The findings suggest potential synergistic effects resulting from the doping strategy. The study expands knowledge on biochar production from diverse biomass sources and highlights the potential for utilizing lignocellulosic and non-lignocellulosic biomass waste materials for sustainable biochar production.

Comprehensive review on lignocellulosic biomass derived biochar production, characterization, utilization and applications

Biochar is an ample source of organic carbon prepared by the thermal breakdown of biomass. Lignocellulosic biomass is a promising precursor for biochar production, and has several applications in various industries. In addition, biochar can be applied for environmental revitalization by reducing the negative impacts through intrinsic mechanisms. In addition to its environmentally friendly nature, biochar has several recyclable and inexpensive benefits. Nourishing and detoxification of the environment can be undertaken using biochar by different investigators on account of its excellent contaminant removal capacity. Studies have shown that biochar can be improved by activation to remove toxic pollutants. In general, biochar is produced by closed-loop systems; however, decentralized methods have been proven to be more efficient for increasing resource efficiency in view of circular bio-economy and lignocellulosic waste management. In the last decade, several studies have been conducted to reveal the unexplored potential and to understand the knowledge gaps in different biochar-based applications. However, there is still a crucial need for research to acquire sufficient data regarding biochar modification and management, the utilization of lignocellulosic biomass, and achieving a sustainable paradigm. The present review has been articulated to provide a summary of information on different aspects of biochar, such as production, characterization, modification for improvisation, issues, and remediation have been addressed.

Home Trash Biomass Valorization by Catalytic Pyrolysis

With the increase in population, large amounts of food waste are produced worldwide every day. These leftovers can be used as a source of lignocellulosic waste, oils, and polysaccharides for renewable fuels. In a fixed bed reactor, low-temperature catalytic pyrolysis was investigated using biomass gathered from domestic garbage. Thermogravimetry, under N2 flow, was used to assess the pyrolysis behavior of tea and coffee grounds, white potato, sweet potato, banana peels, walnut, almonds, and hazelnut shells. A mixture of biomass was also evaluated by thermogravimetry. Waste inorganic materials (marble, limestone, dolomite, bauxite, and spent Fluid Catalytic Cracking (FCC) catalyst) were used as catalysts (16.7% wt.) in the pyrolysis studies at 400 °C in a fixed bed reactor. Yields of bio-oil in the 22–36% wt. range were attained. All of the catalysts promoted gasification and a decrease in the bio-oil carboxylic acids content. The marble dust catalyst increased the bio-oil volatility. The results show that it is possible to valorize lignocellulosic household waste by pyrolysis using inorganic waste materials as catalysts.

Enhanced integrative process of hydrothermal carbonization and anaerobic digestion with hydrochar addition from lignocellulosic waste

Enhanced integrative process of hydrothermal carbonization and anaerobic digestion with hydrochar addition from lignocellulosic waste

Nitrate Uptake by Cellulose-Based Anion Exchange Polymers Derived from Wheat Straw

Nitrate contamination of ground water is a serious problem due to the intensive agricultural activities needed to feed the world’s growing population. While effective, drinking water treatment using commercial ion exchange polymers is often too expensive to be employed. At the same time, lignocellulosic waste from crop production—an abundant source of the renewable polymer cellulose—is often burned to clear fields. This results in not only adverse health outcomes, but also wastes a valuable resource. In this study, wheat straw was pretreated to extract cellulose, then selectively oxidized with periodate, crosslinked with an alkyl diamine (1,7-diaminoheptane or 1,10-diaminodecane), and functionalized with a quaternary ammonium compound ((2-aminoethyl)trimethyl ammonium chloride) to generate a cellulose-based anion exchange polymer. This polymer lowered aqueous nitrate concentrations to health-based drinking water standards. Unlike commercial ion exchange polymers, its synthesis did not require the use of toxic epichlorohydrin or flammable solvents. The pretreatment conditions did not significantly affect nitrate uptake, but the crosslinker chain length did, with polymers crosslinked with 1,10-diaminodecane showing no nitrate uptake. Agricultural-waste-based anion exchange polymers could accelerate progress toward the sustainable development goals by providing low-cost materials for nitrate removal from water.

Isolation of xylose-utilizing yeasts from oil palm waste for xylitol and ethanol production

The energy crisis triggers the use of energy sources that are renewable, such as biomass made from lignocellulosic materials, to produce various chemical compounds for food ingredients and biofuel. The efficient conversion of lignocellulosic biomass into products with added value involves the activity of microorganisms, such as yeasts. For the conversion, microorganisms must be able to use various sugars in lignocellulosic biomass, including pentose sugars, especially xylose. This study aims to isolate xylose-utilizing yeasts and analyze their fermentation activity to produce xylitol and ethanol, as well as their ability to grow in liquid hydrolysate produced from pretreated lignocellulosic biomass. Nineteen yeast isolates could grow on solid and liquid media using solely xylose as a carbon source. All isolates can grow in a xylose medium with incubation at 30 °C, 37 °C, 42 °C, and 45 °C. Six isolates, namely SLI (1), SL3, SL6, SL7, R5, and OPT4B, were chosen based on their considerable growth and high xylose consumption rate in a medium with 50 g/L xylose with incubation at 30 °C for 48 h. Four isolates tested, namely SLI (1), SL6, SL7, and R5, can produce xylitol in media containing xylose carbon sources. The concentration of xylitol produced was determined using high-pressure liquid chromatography (HPLC), and the results ranged from 5.0 to 6.0 g/L. Five isolates tested, namely SLI (1), SL6, SL3, R5, and OPT4B, can produce ethanol. The ethanol content produced was determined using gas chromatography (GC), with concentrations ranging from 0.85 to 1.34 g/L. Three isolates, namely SL1(1), R5, and SL6, were able to produce xylitol and ethanol from xylose as carbon sources and were also able to grow on liquid hydrolyzate from pretreated oil palm trunk waste with the subcritical water method. The three isolates were further analyzed using the 18S rDNA sequence to identify the species and confirm their phylogenetic position. Identification based on DNA sequence analysis revealed that isolates SL1(1) and R5 were Pichia kudriavzevii, while isolate SL6 was Candida xylopsoci. The yeast strains isolated from this study could potentially be used for the bioconversion process of lignocellulosic biomass waste to produce value-added derivative products.Graphical

Taxonomy, Ecology, and Cellulolytic Properties of the Genus Bacillus and Related Genera

Bacteria of the genus Bacillus and related genera (e.g., Paenibacillus, Alicyclobacillus or Brevibacillus) belong to the phylum Firmicutes. Taxonomically, it is a diverse group of bacteria that, to date, has not been well described phylogenetically. The group consists of aerobic and relatively anaerobic bacteria, capable of spore-forming. Bacillus spp. and related genera are widely distributed in the environment, with a particular role in soil. Their abundance in the agricultural environment depends mainly on fertilization, but can also depend on soil cultivated methods, meaning whether the plants are grown in monoculture or rotation systems. The highest abundance of the phylum Firmicutes is usually recorded in soil fertilized with manure. Due to the great abundance of cellulose in the environment, one of the most important physiological groups among these spore-forming bacteria are cellulolytic bacteria. Three key cellulases produced by Bacillus spp. and related genera are required for complete cellulose degradation and include endoglucanases, exoglucanases, and β-glucosidases. Due to probable independent evolution, cellulases are encoded by hundreds of genes, which results in a large structural diversity of these enzymes. The microbial degradation of cellulose depends on its type and environmental conditions such as pH, temperature, and various substances including metal ions. In addition, Bacillus spp. are among a few bacteria capable of producing multi-enzymatic protein complexes called cellulosomes. In conclusion, the taxonomy of Bacillus spp. and related bacteria needs to be reorganized based on, among other things, additional genetic markers. Also, the ecology of soil bacteria of the genus Bacillus requires additions, especially in the identification of physical and chemical parameters affecting the occurrence of the group of bacteria. Finally, it is worth adding that despite many spore-forming strains well-studied for cellulolytic activity, still few are used in industry, for instance for biodegradation or bioconversion of lignocellulosic waste into biogas or biofuel. Therefore, research aimed at optimizing the cellulolytic properties of spore-forming bacteria is needed for more efficient commercialization.

Exploring Hydrochars from Lignocellulosic Wastes as Secondary Carbon Fuels for Sustainable Steel Production.

This study investigates the suitability of different lignocellulosic sources, namely eucalyptus, apple bagasse, and out-of-use wood, for injection into blast furnaces (BFs). While wastes possess carbon potential, their high moisture renders them unsuitable for direct energy utilization. Additionally, the P and K impurities, particularly in apple bagasse, can pose operational and product quality challenges in BF. Thus, different thermochemical processes were performed to convert raw biomass into a more suitable carbon fuel. Low-temperature carbonization was selected for eucalyptus, yielding a biochar with properties closer to the low-rank coal. Hydrothermal carbonization was chosen for apple bagasse and out-of-use wood, resulting in hydrochars with enhanced fuel characteristics and fewer adverse inorganic species but still limiting the amount in binary PCI blends. Thermogravimetry evaluated the cause-effect relationships between coal and coal- and bio-based chars during co-pyrolysis, co-combustion and CO2-gasification. No synergistic effects for char formation were observed, while biochars benefited ignition and reactivity during combustion at the programmed temperature. From heat-flow data in combustion, the high calorific values of the chars were well predicted. The CO2-gasification profiles of in situ chars revealed that lignin-rich hydrochars exhibited higher reactivity and conversion than those with a higher carbohydrate content, making them more suitable for gasification applications.