Alternative Source Of Biomass Research Articles

Effects of season, depth and pre-cultivation fertilizing on Ulva growth dynamics offshore the Eastern Mediterranean Sea

Offshore macroalgae production could provide an alternative source of biomass for food, materials and energy. However, the offshore environment in general, specifically the Eastern Mediterranean Sea (EMS) offshore, is a high energy and low nutrients environment, thus challenging for macroalgae farming. In this study, we experimentally investigated the impact of season, depth, and pre-cultivation fertilization duration on the growth rates and chemical composition of offshore Ulva biomass, and developed a predictive model tailored to offshore conditions, capable of estimating both biomass growth rate and nitrogen content. Specifically, we measured Ulva biomass growth rate and internal nitrogen in the nitrogen-poor EMS a few kilometers offshore the Israeli coast at various depths and on-shore pre-cultivation fertilization schedules. Based on these data, we constructed a predictive cultivation model of Ulva offshore growth, which allows for the optimization of fertilization requirements for offshore cultivation. This study provides new insights on the effects of seasonality, depth, and pre-cultivation fertilization duration on growth rates and chemical composition of offshore Ulva sp. biomass production.

Non-Catalytic and Catalytic Conversion of Fruit Waste to Synthetic Liquid Fuel via Pyrolysis

Plum stone stands out as an alternative biomass source in terms of obtaining fuel and chemicals with or without catalysts under different conditions. Under variable heating rates (10, 50, and 100 °C min−1) and pyrolysis temperatures (400, 450, 500, 550, and 600 °C), plum stone was pyrolyzed at a constant rate in a constant sweep gas flow (100 cm3 min−1) in a tubular fixed-bed reactor. According to the results, an oil yield reaching a maximum of 45% was obtained at a heating rate of 100 °C min−1 and pyrolysis temperature of 550 °C in the non-catalytic procedure. The catalytic pyrolysis was carried out with two selected commercial catalysts, namely ZSM-5 and PURMOL-CTX and clinoptilolite (natural zeolite, NZ) under optimum conditions with a catalyst ratio of 10% of the raw material. With the addition of catalyst, the quantity and quality of bio-oil increased, including calorific capacity, the removal of oxygenated groups, and hydrocarbon distribution. In the presence of catalysts, an increase was observed in terms of desirable products such as phenol, alkene, and alkane, and a decrease in terms of undesirable products such as acids. Considering and evaluating all the results, the use of zeolite materials as catalysts in pyrolysis is a recommended option for obtaining enhanced chemicals and fuels.

Life Cycle Assessment of PLA Products: A Systematic Literature Review

The rising concerns about environmental harm and pollution create a setting for the search for better materials to produce more sustainable products. Plastic plays a crucial role in modern life and most of the commonly used are of fossil origin. Polylactic Acid (PLA) has been appointed as a more sustainable alternative, due to its origins in biodegradable raw materials. This paper aims to review scientific research, where Life Cycle Assessment (LCA) is performed on this material, in order to further understand the environmental impacts and to assess whether it is a more viable option when compared to the most commonly used plastics. A systematic literature review of 81 LCA studies focused on the LCA of PLA products was conducted. An assessment of key aspects, including the system boundaries, raw materials origin, and quantitative analysis of five environmental impact categories was performed. In this comparative analysis, in addition to presenting the results for PLA products, they are also compared with other fossil-based plastics. This leads to the conclusion that PLA has higher environmental impacts on Marine Eutrophication, Freshwater Eutrophication, and Human Toxicity, which are mainly related to the agricultural phase of growing the raw materials for PLA production. For Climate Change, Polystyrene (PS) presents the higher Greenhouse Gas (GHG) emissions, and for the Ozone Layer Depletion category, Polyethylene terephthalate (PET) presents the higher impact. PLA is a solution to replace fossil plastics. However, the use of alternative biomass sources without competition with the feed and food sector could be a key option for biobased materials production, with lower environmental and socioeconomic impacts. This will be a pathway to reduce environmental impacts in categories such as climate change, marine eutrophication, and freshwater eutrophication.

Management of invasive shrubs to mitigate wildfire through fuel pellet production in central Chile

The use of pellets as a replacement for firewood has been promoted in Chile to mitigate atmospheric pollution. However, their high demand has generated stock shortages, which has motivated the search for alternative sources of feedstock. Furthermore, invasive shrubs are a highly available biomass source for bioenergy production in central-southern Chile and may be a significant factor contributing to the spread and increasing virulence observed in wildfires across the region. This study aimed to determine the change in wildfire indicators related to the removal of invasive shrubs in selected zones in the Biobío region and to assess the physicochemical properties of the extracted biomass to develop a pellet formulation to produce a material conforming to ISO standards. The biomass management of Teline monspessulana, Ulex europaeus, and Rubus ulmifolius was evaluated using a fire simulation tool in three areas with contrasting physio-climatic conditions. Our simulation results demonstrated the effectiveness of shrub management on three critical wildfire indicators. Namely, significant decreases were observed in fireline intensity (kW/m) 58–75%, flame length (m) 0–40%, and heat per unit area (kW/m2) 86%. Furthermore, a biomass quality index (BQI) was developed based on the physicochemical parameters of the three shrubs assessed. Based on this BQI, T. monspessulana was selected as the most promising shrub biomass and was consequently used in a pilot shrub-pinewood blending to produce pellets. A blending of 20:80%m/m exhibited properties close to the ISO standard. Our results show that the management of invasive shrubs has the potential to minimize the virulence of wildfires, while the physicochemical characteristics and availability of one of the shrubs analyzed (T. monspessulana) make it a viable alternative biomass source for pellet production in the region.

Bioeconomy Adaptation to Climate Change: A Case Study of Food Waste in Slovakia

Abstract Climate change, periods of droughts or, conversely, increased rainfall significantly affect agronomic patterns and biomass production. In addition, if agriculture and food industry compete with other industries for land and biomass, the priority is given to agro-food use and ensuring food security. This is the main reason why food waste is a promising alternative source of biomass for the industrial segment of the bioeconomy. Moreover, the reuse of food waste leads to circular and sustainable value chains. The aim of this paper is to explore the situation of food waste utilization in Slovakia. We assess the current level of food waste produced by households and its potential as a biomass source. However, to convert food waste into a valid industrial input, it has to be collected separately. The study shows the practice of food waste collection in two Slovak cities, where food waste is used to produce soil substrate and bioelectricity, respectively.

Posidonia oceanica Balls (Egagropili) from Kefalonia Island Evaluated as Alternative Biomass Source for Green Energy

Research attempts on biomass use constitute a response to the growing demand for sustainable and low-cost energy from renewable sources. Hence, the sustainable use of Posidonia oceanica (PO) waste as a material for biomass to produce green energy is being considered in many countries in the Mediterranean region. PO meadows are considered as the main type of sea flora in the Greek coasts. PO can extract biomass from nearby ecosystems of the coastal zone, either directly through the transportation of disposed non-living leaves or indirectly via benthic organisms. The aim of this study is to investigate the use of PO waste derived from Kefalonia Island (Greece) as a biomass source. PO samples were collected around the island, and they were mineralogically and microstructurally analyzed. In addition, physicochemical, chemical, and thermogenic tests were performed in order to obtain the optimum and most completed characterization of the material. Based on the results, cellulose seems to be the main structural component of PO, which also seems to determine their behavior. PO presents microscopic similarities to other lignocellulosic materials which composition is made of carbonates, lignin, extractives, and minerals. Ash and moisture content constitute the two critical parameters that are responsible for the energy differences of each biomass. The outcome of this study shows the potential use of PO wastes as an interesting source for energy production.

Biomass Fuel Production through Cultivation of Microalgae Coccomyxa dispar and Scenedesmus parvus in Palm Oil Mill Effluent and Simultaneous Phycoremediation

Palm oil mill effluent (POME) is a potential alternative sources of biomass fuel upon phycoremediation treatment using microorganisms. In this study, Coccomyxa dispar and Scenedesmus parvus, as acidophilic microalgae, were used to investigate growth and the production of biomass fuel from the cultivation of POME, as well the effectiveness of removing contaminants from POME. Individual cultivation was conducted at 26 ± 3 °C for 14 days under three growth modes (mixotrophic, heterotrophic, and autotrophic). To elucidate the potential phycoremediation properties, the characteristics of treated POME were compared, such as optical density (OD), cell dry weight (CDW), calorific energy values (CEV), chemical oxygen demand (COD), biochemical oxygen demand (BOD), carbon, hydrogen, and nitrogen (CHN) elemental analysis, including oil and grease content. S. parvus exhibits an outstanding growth profile for all growth modes compared to C. dispar, with measurements of 228.8, 37.08, and 118.2 mg/L observed at day 14 of cultivation. The highest CEV is 32.30 MJ/kg, which was obtained from S. parvus in the mixotrophic mode. Maximum removal efficiency for COD and BOD was 81% and 19% in the mixotrophic growth mode with S. parvus. These results pinpoint that S. parvus has the potential to be utilized for biomass fuel production with high CEV and effective POME phycoremediation.

Evaluation of Economic Possibilities of Production of Second-Generation Spirit Fuels for Internal Combustion Engines in Poland

With the rapid growth in industrial development, there is a particular need for new environmentally balanced energy source utilization. Ethanol produced from biomass, especially lignocellulosic waste products, represents an attractive, sustainable energy source for fuel production. Until now, in Poland, bioethanol has been produced from edible plants containing sugars susceptible to fermentation. Due to the growing technical and economical needs for alternative biomass source utilization, in the present work, an attempt has been made to identify the most cost-effective strategy to analyze ethyl alcohol production from different lignocellulose sources. The concept of an installation for the first and second stages of bioethanol production was proposed. All of the most relevant elements of the bioethanol production cost analysis were identified and characterized. Cost analyses of all important production process elements showed their relative effects on the production cost and potential for the competitive advantage of applied raw material. The study demonstrates the importance of renewable energy source utilization and the cost-effectiveness of bioethanol production. Furthermore, the proposed less energy- and labor-demanding process, primarily achieved via the implementation of technological medium recovery and recirculation, reduces the production cost and results in higher production efficiency, and therefore has a significant effect on the overall process economy.

Environmental productivity index GIS‐based model to estimate prickly pear biomass potential availability for biogas production

AbstractNowadays, climate change is the environmental issue facing the world. To reach the 2030 European Union goals, recently, biogas production through anaerobic digestion has developed significantly, by using alternative biomass sources due to the competition between food and no‐food products. In this regard, Opuntia ficus‐indica (OFI) has been suggested as a suitable new biomass for producing biomethane within the context of circular economy. In this study, a predictive methodology was applied by combining the Nobel model of environmental productivity index (EPI) and geographic information system (GIS), with the aim of estimating OFI biomass amount, as well as biogas and electricity potential production. The GIS analyses allowed the identification of the most suitable territorial areas for producing biogas from OFI, and an estimation of electricity production. The achieved results are highly valuable information for strategic planning of biogas sector development and could be relevant to the intervention priorities established by the EU.

Modern Technologies for Converting Microalgae Biomass into Various Kinds of Biofuel

Searching for alternative sources of biomass as a raw material for bioenergy is currently an urgent fundamental and applied scientific problem. Microalgae, due to the peculiarities of their physiology, high productivity, and the potential to consume carbon dioxide from the atmosphere, are one of the examples of such sources. The article presents the results of long-term research conducted at the Moscow State University’s Laboratory of Renewable Energy Sources on developing a technology for large-scale cultivation of microalgae, methods for increasing their productivity in terms of biomass and target products (lipids and carbohydrates), and obtaining various types of biofuels from biomass (biodiesel, bio-oil, synthesis gas, methane, etc.). The possibility of associated wastewater treatment, CO2 utilization, and obtaining of valuable by-products in the industrial cultivation of microalgae is shown.

Chemical and technological attributes of sugarcane as functions of organomineral fertilizer based on filter cake or sewage sludge as organic matter sources.

Sugarcane is one of the main alternative sources of biomass for the biofuel sector, and its large-scale production has considerable environmental impact. Organomineral fertilizers formulated with potential environmental contaminants, such as filter cake and sewage sludge, positively influence plant growth and development. The objective of the present study was to evaluate the chemical and physical characteristics of sugarcane fertilized with pelletized organomineral fertilizers based on filter cake or sewage sludge. Eight field treatments were applied, based on three organomineral fertilizer compositions (50%, 100%, and 150%) associated with two organic matter (OM) sources (filter cake or sewage sludge), in addition to a control with 100% mineral fertilizer application, and a no-fertilization control (0%). Sugarcane attributes were evaluated during two consecutive harvests. The weights of stalks per hectare (ton ha-1), sugarcane productivity (ton ha-1), quantity of sugar per hectare (TSH, ton ha-1), and physicochemical properties of sugarcane juice (pol [%], Brix [%], purity [%], and fiber [%]) were evaluated. There were no significant differences in the attributes between OM sources or organomineral fertilization treatments and the exclusive mineral fertilization. The organomineral fertilizer application rate recommended for maximum quantitative and qualitative sugarcane in the first sugarcane harvest was between 2 and 9% above the regular recommendation for mineral fertilizer, regardless of the OM source. In the second harvest, the sewage sludge source increased total sugar and sugarcane per hectare by 4.68 and 4.19%, respectively, compared to the sugarcane filter cake source. Sewage sludge and sugarcane filter cake are viable alternatives for organomineral composition and could improve economic returns and minimize negative environmental impacts in sugarcane cultivation systems.

Biodiesel from Microalgae: Advantages and Future Prospective

Biofuel is considered as a solution to substitute petroleum fuel and to reduce the carbon dioxide emissions contributing to global warming. The most known biofuels used are biodiesel, bioethanol, and biohydrogen extracted from biomass. For a long time, these biofuels were produced from edible crops that compete with the food of humans and animals. Therefore, research is focused worldwide on alternative biomass sources. Scientists are looking for innovative biofuel feedstocks such as agricultural wastes, algae, and jatropha. The first generation of biodiesel mainly depended on vegetable oils for conversion to methyl esters and glycerol. In Johannesburg, South Africa, the 2002 World Summit on Sustainable Development pledged to promote renewable energy sources. At the United Nations Climate Change Conference (COP21) in Paris in 2015, 174 countries pledged to work together to keep global warming well below 2 degrees Celsius by supporting more renewable energy investment. Algae are one of the very promising feedstocks for biofuel production.

Biogas production from Napier grass and cattle slurry using a green energy technology

The use of alternative biomass sources that are not competitive with food production is intended for sustainable management in biogas production through anaerobic digestion. This study investigates the Napier grass and cattle slurry-based biogas production application that could be applied more cost-effectively more sustainable production biogas. The laboratory-based biogas plant and a biogas plant in practice revealed that the results from the laboratory experiments were realistic and transferable into practice. The effect of feedstock screening on the biogas yield of Napier grass and cattle slurry was evaluated in batch digesters under mesophilic conditions. Moreover, highest methane content was reached 64.4%. The biogas from the co-digestion of Napier grass and cow farm slurry containing the higher calorific value was 25.69 MJ/m3, and the lower calorific value was 23.14 MJ/m3 . The results demonstrated that combining Napier grass with common cow farm slurry can accelerate the reaction, increase efficiency, and increase methane content. Therefore, the co-digestion of Napier grass and cow farm slurry was a promising method for increasing biogas production.

A production of bioethanol through the bioconversion of water hyacinth: A review

The demand for energy is increasing due to the rapid progress of industrial development while the amount of fossil fuels is decreasing day by day. Scientists are constantly looking for alternative sources of fossil fuels that will be sustainable but not harmful to the environment. Ethanol from biomass is an attractive, sustainable, and less toxic, less polluting fuel source in the modern era and the age of industrialization. The lignocellulose present in water hyacinth is a renewable source which is considered as a suitable alternative source of biomass for energy production. Cellulose aquatic plants are water hyacinth which have high carbohydrate, low lignin content and significantly lower reducing sugar infrastructure which is converted to fermentable sugar and later to ethanol. Ethanol production from water hyacinth involves two main types of conventional processes, firstly, lignin removal by pre-treatment of plant components, secondly, conversion of pre-treatment material to bioethanol through hydrolysis and fermentation process. This paper reviews all the conventional processes of making bioethanol from water hyacinth. The hydrolysis process mainly for acid and alkali and the fermentation process of yeast used for the production of bioethanol from water hyacinth have been discussed comparatively. Due to its low cost and easy availability, bioethanol from water hyacinth makes a strong promise in the 21st century.

Improving the physical, mechanical and energetic properties of Quercus spp. wood pellets by adding pine sawdust.

BackgroundBiomass usage for energy purposes has emerged in response to global energy demands and environmental problems. The large amounts of by-products generated during logging are rarely utilized. In addition, some species (e.g., Quercus spp.) are considered less valuable and are left in the cutting areas. Production of pellets from this alternative source of biomass may be possible for power generation. Although the pellets may be of lower quality than other types of wood pellets, because of their physical and technological properties, the addition of different raw materials may improve the characteristics of the oak pellets.MethodsSawdust from the oak species Quercus sideroxyla, Q. rugosa, Q. laeta and Q. conzattii was mixed with sawdust from the pine Pinus durangensis in different ratios of oak to pine (100:0, 80:20, 60:40, 40:60 and 20:80). Physical and mechanical properties of the pellets were determined, and calorific value tests were carried out. For each variable, Kolmogorov–Smirnov normality and Kruskal–Wallis tests were performed and Pearson’s correlation coefficients were determined (considering a significance level of p < 0.05).ResultsThe moisture content and fixed carbon content differed significantly (p < 0.05) between the groups of pellets (i.e., pellets made with different sawdust mixtures). The moisture content of all pellets was less than 10%. However, volatile matter and ash content did not differ significantly between groups (p ≥ 0.05). The ash content was less than 0.7% in all mixtures. The addition of P. durangensis sawdust to the mixtures improved the bulk density of the pellets by 18%. Significant differences (p < 0.05) in particle density were observed between species, mixtures and for the species × mixture interaction. The particle density was highest in the 80:20 and 60:40 mixtures, with values ranging from 1,245 to 1,349 kg m−3. Bulk density and particle density of the pellets were positively correlated with the amount of P. durangensis sawdust included. The mechanical hardness and impact resistance index (IRI) differed significantly (p < 0.05) between groups. The addition of pine sawdust decreased the mechanical hardness of the pellets, up to 24%. The IRI was highest (138) in the Q. sideroxyla pellets (100:0). The mechanical hardness and IRI of the pellets were negatively correlated with the amount of P. durangensis sawdust added. The bulk density of the pellets was negatively correlated with mechanical hardness and IRI. The calorific value of mixtures and the species × mixture interaction differed significantly between groups. Finally, the mean calorific value was highest (19.8 MJ kg−1) in the 20:80 mixture. The calorific value was positively related to the addition of P. durangensis sawdust.

Simultaneous fermentation of galacturonic acid and five-carbon sugars by engineered Saccharomyces cerevisiae

Pectin-rich biomass has garnered attention as an alternative biomass source. However, some monomers derived from pectin-rich biomass, namely d-galacturonic acid, l-arabinose, and d-xylose, are not fermentable by industrial microorganisms such as Saccharomyces cerevisiae. The purpose of this study is to develop a S. cerevisiae strain capable of fermenting the pectin monomers. Expressions of eight heterologous genes and deletion of two endogenous genes, all of which were successfully completed by Cas9-based in vivo assembly and integration strategy, allowed the consumption of pectin monomers as sole carbon sources. To facilitate the consumption of galacturonic acid, which had the most limitations, the use of a co-substrate was tested using various sugars. As a result, we found that arabinose and xylose allowed simultaneous consumption of galacturonic acid. Based on intracellular metabolite profiling, it was concluded that the five-carbon sugars partially resolve the metabolic bottleneck of galacturonic acid.

Valorization of Eucalyptus nitens bark by organosolv pretreatment for the production of advanced biofuels

The biofuels production from alternative and renewable raw materials is mandatory to achieve sustainable growth based on a bioeconomy. Eucalyptus bark is a waste generated during the chemical manufacturing of Eucalyptus pulp that can be used as an alternative source of biomass, suitable for the production of biofuels. In this work, Eucalyptus nitens bark (ENB) was fractionated by organosolv treatment for ethanol production. For that, a Doehlert experimental design was carried out to evaluate the dependent variables: temperature (170–200 °C), time (30–90 min) and ethanol-water percentage (50–80 %) on delignification of Eucalyptus bark. Organosolv process was suitable for the fractionation of E. nitens bark. After treatment, 74–93 % of glucan was recovered and 25–52 % of delignification was achieved. Delignified ENB was subjected to simultaneous saccharification and fermentation process for bioethanol production. The results showed that the variables temperature and time of organosolv process had significant influence on ethanol production. The organosolv pretreatment improved the ethanol yield from 32 to 99%. This work shows a suitable process for the valorization of Eucalyptus bark into bioethanol.

The potential of quantitative models to improve microalgae photosynthetic efficiency.

The massive increase in carbon dioxide concentration in the atmosphere driven by human activities is causing huge negative consequences and new sustainable sources of energy, food and materials are highly needed. Algae are unicellular photosynthetic microorganisms that can provide a highly strategic contribution to this challenge as alternative source of biomass to complement crops cultivation. Algae industrial cultures are commonly limited by light availability, and biomass accumulation is strongly dependent on their photon-to-biomass conversion efficiency. Investigation of algae photosynthetic metabolism is thus strategic for the generation of more efficient strains with higher productivity. Algae are cultivated at industrial scale in conditions highly different from the natural niches they adapted to and strains development efforts must fully consider the seminal influence on productivity of regulatory mechanism of photosynthesis as well as of cultivation parameters like cells concentration, light distribution in the culture, mixing, nutrients and carbon dioxide availability. In this review we will focus in particular on how mathematical models can account for the complex influence of all environmental parameters and can be exploited for development of improved algae strains.

Green biomass to biogas – A study on anaerobic digestion of residue grass

Sustainable management in the biogas production via anaerobic digestion process intents the use of alternative biomass sources that are not competitive with food production. The aim of this study is to investigate the application of the abundant-quantity residue in more sustainable production of heat and electricity along with the production of the digested substrate as a fertiliser. The study has been divided into several sequential steps. First, the grass samples have been collected at the following locations: uncultivated land, river embankment and highway verge. The greatest grass yield has been determined for the riverbank grass, with an average value of 19 t/ha of fresh mass and 2.6 t/ha of dry mass. Next, the chemical characterisation of the collected residue grass and the laboratory batch mono and co-digestion tests with maize silage and cattle slurry have been conducted. The results show that all grass samples have satisfying digestive parameters (C/N ratio between 16.6:1 to 22.8:1) with the low presence of impurities, which makes them suitable for biogas production. The following biochemical methane potential in mono-digestion of residue grass has been recorded: uncultivated land (0.275 Nm3/kgTS), riverbank (0.192 Nm3/kgTS) and highway verge (0.255 Nm3/kgTS). The control of the process has been improved in co-digestion tests, by avoiding acidification in the first days of the operation. The estimation of kinetic parameters in mathematical modelling has shown that the degradation of residue grass shows some different parameters compared to the previous study. The model results for the gas phase show some small deviations compared to the experimental data. Based on the life cycle analysis results it can be concluded that there are perspectives in the use of residual grass compared to maize silage in the production of heat and electricity, especially in the improvement of ecosystem quality.

Physical, mechanical and energy characterization of wood pellets obtained from three common tropical species

BackgroundThe need for energy sources with low greenhouse gas emissions and sustainable production encourages the search for alternative biomass sources. However, the use of biomass fuels faces the problem of storage, transport and lower energy densities. Low-density values can negatively affect energy density, leading to an increase in transportation and storage costs. Use of pellets as alternative biomass source is a way to reduce the volume of biomass by densification, which improves their energy quality. They are produced by diverse biomass resources and mainly from wood materials. In all cases, it is important to evaluate the fuel characteristics, to determine their suitability on the heating system and handling properties.MethodsThe present study determines and compares data from proximate analysis, calorific values, physical and mechanical properties of wood pellets produced from the common tropical species Acacia wrightii, Ebenopsis ebano and Havardia pallens. Data were obtained from pellets produced from each species chips collected from an experimental plantation and analyzed through ANOVA and Kruskal–Wallis test at 0.05 significance level.ResultsThe results of diameter, length and length/diameter ratio didn’t show statistical differences (p > 0.05) among species. Acacia wrightii showed the highest density (1.2 g/cm3). Values on weight retained and compression test showed statistical differences (p = 0.05) among species. Havardia pallens was more resistant to compression strength than A. wrightii and Ebenopsis ebano. Statistical differences (p < 0.01) were also observed for the volatile matter and calorific value. E. ebano has the lowest volatile matter (72%), highest calorific value (19.6 MJ/kg) as well as the fixed carbon (21%).DiscussionThe pellets of the species studied have a high energy density, which makes them suitable for both commercial and industrial heating applications.A pellet with low compression resistance tends to disintegrate easily, due to moisture adsorption. The percentages obtained for the resistance index were higher than 97.5%, showing that the pellets studied are high-quality biofuels. Proximate analysis values also indicate good combustion parameters. Pellets of Acacia wrightii and Ebenopsis ebano are the more favorable raw material sources for energy purposes because of their high density, calorific value, low ash content and they also met majority of the international quality parameters.