Biomass

AlCl₃·6H₂O was used as a catalyst in the esterification reaction of levulinic acid with 1-hexanol for producing hexyl levulinate, a compound that finds applications in several industrial sectors and represents an excellent candidate to be used in diesel fuel blends. A kinetic and thermodynamic study of the esterification reaction was performed, considering four different temperatures (338, 348, 358, and 368 K), an acid: alcohol: catalyst 1:1:0.01 molar ratio, and a reaction time of 72 h. An optimization study was then carried out, evaluating the effect of alcohol and catalyst amounts, and, in the best reaction conditions (acid:alcohol:catalyst 1:2:0.1), a very high levulinic acid conversion (92.5%) was achieved. By using AlCl₃·6H₂O, alongside the high reaction yield, the product purification was also simplified, being such a catalyst able to trap most of the water in a different phase than hexyl levulinate, and, furthermore, it was found to be completely recoverable and reusable for several reaction cycles, without losing its catalytic effectiveness. The use of AlCl₃·6H₂O, therefore, represents a promising effective green route for obtaining hexyl levulinate. Full article

The influence of microaeration, pH, and substrate during dark fermentation of sour cabbage, gelatin, and wheat straw was investigated, and the results of dark fermentation of these three substrates and their mixtures are presented in this research. The fermentation of cabbage, gelatin, and wheat straw was investigated under varying pH and aeration conditions. We investigated concentrations of volatile suspended solids (VSS) of 20 g VSS/L of a substrate at a stable pH of 6.0 and a not aligned pH value. Sour cabbage resulted in the highest volume of hydrogen for 450 mL/g VSS with a pH of 6.0. The mixing of substrates caused lower hydrogen production than sour cabbage or wheat straw alone. Full article

This study evaluated the feasibility of producing solid recovered fuel (SRF) from rejected waste from waste picker cooperatives (WPC). Three scenarios using different SRF and petroleum coke proportions in cement kilns were assessed. The samples of rejected waste from WPC were obtained in the city of Florianópolis, Brazil, and their physical and chemical characteristics were determined. Furthermore, the avoided atmospheric emissions by replacing conventional cement fuel with SRF and the costs to implement a SRF facility were estimated. According to the results, 60.29% of the waste from WPC could be used for energy recovery. Out of the materials eligible to produce SRF, 75.26% are made up of plastic packaging and paper. Concerning atmospheric emissions, replacing petroleum coke with SRF for direct feeding into the clinker kiln contributed to a reduction of 4.83%, 14.73%, and 13.37% in the atmospheric emissions for Scenario 1, Scenario 2, and Scenario 3, respectively. Furthermore, considering two hypothetical SRF industrial plants with capacities of 522 and 720 t/day, each ton of SRF produced would cost about USD 6.00, representing a decrease of 35 times in the costs when compared to petroleum coke. Therefore, SRF from the rejected fraction of WPC could be an alternative waste-to-energy approach. Full article

Brewers’ spent grain (BSG) is an important waste produced by beer companies and has a high potential to be transformed into commercial by-products. The present paper reports a forecasting technology study with the aid of bibliographic review and patent analysis tools aiming to investigate the maturity of certain technologies, considering the use of BSG on a closed-loop biorefinery and circular bioeconomy concept integrated into a brewery. To evaluate the possibilities of production of high-added-value products in Brazil, we present an overview of BSG’s scientific, technological, and marketing products and applications. The comparison between the numbers of articles versus patents shows that the solutions proposed by research articles are not being transformed into maturated viable technologies. The results suggest that there is a gap between the scientific research in the institutions and their applications in the industry, which lead to the destination of BSG for more economically attractive investments when compared with research in Brazil. Ultimately, from the carried-out analysis, it is possible to propose a brewing process connected to the biorefinery system, showing its possibility in the newly arising brewery industries. Full article

Canada is a leading global agricultural exporter, and roughly half of Canada’s farmland is in Saskatchewan. New agrivoltaics research shows increased biomass for a wide range of crops. This study looks at the potential increase in crop yield and livestock in Saskatchewan through agrivoltaics along with its financial implications. Then, the legislation that could influence the adoption of agrivoltaics in Saskatchewan is reviewed. Specifically, experimental results from agrivoltaic wheat production are analyzed for different adoption scenarios. The impact of converting the province’s pasture grass areas to agrivoltaics and using sheep to harvest them is also examined. The results indicate that approximately 0.4 million more tons of wheat, 2.9 to 3.5 million more tons of forage and 3.9 to 4.6 million additional sheep can be grazed using agrivoltaics in Saskatchewan. Only these two agrivoltaics applications, i.e., wheat farmland and pastureland, result in potential additional billions of dollars in annual provincial agricultural revenue. The Municipalities Act and the Planning and Development Act were found to have the most impact on agrivoltaics in the province as official community plans and zoning bylaws can impede diffusion. Agrivoltaics can be integrated into legislation to avoid delays in the adoption of the technology so that the province reaps all of the benefits. Full article

In the event of an abrupt sunlight reduction scenario, there is a time window that occurs between when food stores would likely run out for many countries (~6 months or less) and ~1 year when resilient foods are scaled up. A promising temporary resilient food is leaf protein concentrate (LPC). Although it is possible to extract LPC from tree biomass (e.g., leaves and needles), neither the yields nor the toxicity of the protein concentrates for humans from the most common tree species has been widely investigated. To help fill this knowledge gap, this study uses high-resolution mass spectrometry and an open-source toolchain for non-targeted screening of toxins on five common North American coniferous species: Western Cedar, Douglas Fir, Ponderosa Pine, Western Hemlock, and Lodgepole Pine. The yields for LPC extraction from the conifers ranged from 1% to 7.5%. The toxicity screenings confirm that these trees may contain toxins that can be consumed in small amounts, and additional studies including measuring the quantity of each toxin are needed. The results indicate that LPC is a promising candidate to be used as resilient food, but future work is needed before LPCs from conifers can be used as a wide-scale human food. Full article

African countries have been severely affected by food insecurity such that 54% of the population (73 million people) are acutely food insecure, in crisis or worse. Recent work has found technical potential for feeding humanity during global catastrophes using leaves as stop-gap alternative foods. To determine the potential for adopting agricultural residue (especially crop leaves) as food in food-insecure areas, this study provides a new methodology to quantify the calories available from agricultural residue as alternative foods at the community scale. A case study is performed on thirteen communities in Nigeria to compare national level values to those available in rural communities. Two residue utilization cases were considered, including a pessimistic and an optimistic case for human-edible calories gained. Here, we show that between 3.0 and 13.8 million Gcal are available in Nigeria per year from harvesting agricultural residue as alternative food. This is enough to feed between 3.9 and 18.1 million people per year, covering from 10 to 48% of Nigeria’s current estimated total food deficit. Full article

In recent decades, biomasses from different industrial segments have created new interesting perspectives, including sustainable development. Moreover, reusing waste, such as biomass, also impacts the economy, i.e., the circular economy. The main biomasses and their applications are evident in the energy, food, chemistry, fine chemical, and pharmaceutical sectors. Several questions should be asked regarding the trending topic of the circular economy, including biomass availability and seasonality, energy demand (processes), and the real environmental impact. Thus, this review focuses on biomass collected from non-conventional (unusual technology at the industrial scale) food-processing residues, particularly from 2016 to 2023, to produce biomaterials and/or bioproducts for the food sector. Full article

The expansion of bio-based value chains is prioritized through various European Union (EU) policy initiatives. Due to the growing awareness of the importance of a sustainable bioeconomy in Europe, the need to increase the availability and quality of statistics is increasing. There are several essential aspects lacking, including (i) comprehensive databases and statistics for bio-based sectors; (ii) transparent methodology for bio-based data collection; and (iii) integrated value chain data and indicators that illustrate the flows of different bio-based commodities. The aim of this paper is to develop a bio-based material flow monitor to measure the physical contribution of industries to the bioeconomy. The material flow monitor describes physical material flows (including biomass) to, from, and within the economy. It is recorded in the form of supply and use tables. To measure the bioeconomy, the BioSAM database, along with disaggregated commodities and activities, are used. Data regarding waste generation/treatment and CO₂ emissions/sequestrations are added to assess the impact on climate change. The results indicate that the bioeconomy in the EU is underreported due to a lack of data, leading to an insufficient understanding of its contribution to the economy. It can also be concluded that the data from the BioSAM tables are the most complete and have the highest disaggregation level for commodities and sectors, allowing one to measure the significance of the bioeconomy. Full article

Lignin is one of the important components of lignocellulosic cell walls, which endows plant cell walls with rigidity and strength and protects them from microbial invasion. The presence of lignin is thought to hinder the conversion of biomass to bioenergy, so understanding enzyme-lignin interactions is very important in order to reduce the inhibition of lignin and improve the hydrolysis yields. Conversion of lignocellulosic raw materials into bioethanol is divided into pretreatment, enzymatic hydrolysis, and fermentation. In this paper, both pretreatment and enzymatic hydrolysis of lignocellulose are described in detail. Finally, the reasons why lignin hinders enzymatic hydrolysis efficiency, mainly from forming spatial barriers and interacting with cellulase, are discussed, and the influencing factors and mechanisms of action of cellulase hydrolysis are explored with a view to targeted regulation of lignin structure to improve lignocellulosic saccharification. Full article

Seaweed can be a desirable source of renewable energy or fuel after it has been processed by combustion, thermochemical conversion by gasification, pyrolysis, or hydrothermal liquefaction (HTL) or biochemical conversion routes like anaerobic digestion (AD). This work explores how well the measured properties of seaweed pellets match the specifications for the various fuel and energy conversion options listed. Blends of hay, wood chips, sawdust, and seaweed were pelletized. Eight pellet blends with dominant seaweed content and minimum acceptable mechanical strength and stability were produced and their physical and chemical properties were reported. The seaweed pellets had an energy content of around 14 MJ/kg, and each pellet could withstand almost 200 N of compression force. Their water content was around 5% or less and their ash content was around 20–34%. According to the results, a higher wood content increased the energy content of the pellets. Among those properties measured in this project, none of them contradicted the typical specifications of combustion, HTL, and AD. However, the low water content and low strength of some pellet types were unable to meet the specifications for certain types of gasification and pyrolysis. Full article

Apricots are one of the most important fruits in the Mediterranean region for both their nutritional and economic value. They are widely cultivated and consumed fresh or dried or are used in the food industry for the production of jams, juices, etc. In any case, the seeds they contain constitute waste. The kernels are very rich in bioactive compounds such as polyphenols, a fact that makes them very appealing in cosmetology. However, the extraction of the bioactive compounds of apricot kernels is poorly examined. In this study, the preparation of polyphenol-rich extracts from apricot kernel biomass is discussed. To this end, a common extraction procedure with water as a solvent was employed. To enhance the extraction yield, the use of a deep eutectic solvent (DES) was examined. In addition, the use of pulsed electric field (PEF) either as a standalone extraction method or as a complementary step was also examined. According to the results, it was evident that when PEF was applied before the extraction procedure, an increase of 88% in the total polyphenol content (TPC) was recorded. Likewise, the use of a glycerol:choline chloride (2:1, w/w) DES increased the TPC by ~70%. When the two approaches were combined, a 173% increase was recorded. According to the above, it can be concluded that apricot kernel biomass is a very good source of polyphenols, especially using the proposed extraction procedure. Full article

The pyrolysis of lignocellulosic biomass is a promising technology for obtaining renewable chemicals and fuels to replace fossil-based products. However, due to the complexity of the lignin, cellulose and hemicellulose molecules, a large variety of compounds are often formed, making commercial implementation difficult. The use of a catalyst during reactions has been recognized as one of the major improvements in pyrolysis, allowing the production of selected compounds. Moreover, the large number of available catalysts opens up a wide range of possibilities for controlling the reaction network. Zeolites, hierarchical zeolites, alkali and alkaline earth oxides, transition metals and carbonaceous materials, among others, have been investigated in the pyrolysis of a variety of biomasses. In addition, bifunctional catalysts play a role in pyrolysis, as well as the addition of plastics as hydrogen donors. This review aims to present and discuss in detail state-of-the-art catalytic pyrolysis, focusing on the relationships between the properties of the catalysts and the obtained products. A guideline for selecting catalysts for lignocellulosic biomass is also provided. Full article

The objective of this work was to develop an automated anaerobic biodigester capable of operating in a semi-continuous or batch system for biogas production. Low biodegradability biomass has little efficiency in the production of biogas by anaerobic digestion processes and an efficient alternative is the use of bioprocesses in semi-continuous system. Two experiments were carried out in the same proportions but in different processes, and all control and automation parameters were tested and evaluated. For testing, mixtures of organic waste, anaerobic sludge (inoculum) and raw sewage without any treatment from the sewage treatment plant, in mesophilic phase (37 °C), were used during the 60 days of experiment. The semi-continuous system showed the greatest reduction in organic matter, expressed by the removal of 80.7% Total Solids Volatile (TVS) and the greatest volume (68.5 L) and methane percentage (78.5%). Finally, with these and other results found, it is possible to conclude that the biodigester developed for semi-continuous system, with the automation and control system, was satisfactory for the reduction in organic matter and biogas production. In addition, all operating system worked properly and with the use of current, low-cost technologies, the application and development on a larger scale becomes viable in the future. Full article

Ethanol production in Brazil started in the early 1930s due to laws created by the Brazilian government. However, ethanol production only increased significantly with the National Program of Ethanol implementation in 1975. This program was another action taken by the Brazilian government aiming to provide conditions for the development of the ethanol industry in the country. With the program, it was possible to achieve significant progress; however, it finished in the mid-1980s. Currently, ethanol is produced on a large scale by more than 300 sugarcane mills all over the country. In 2016, the Brazilian government provided another incentive for ethanol production by creating the RenovaBio Program, which aimed to reduce greenhouse gas emissions. Besides the environmental aspect, Brazil’s ethanol industry needs to develop to supply future biofuel demand. According to the forecast provided in this paper, and considering technical, economic, and environmental aspects regarding the Brazilian ethanol industry, the current and only feedstock used is likely to be insufficient. Thus, the ethanol produced from corn would be an attractive secondary feedstock to complement sugarcane ethanol as the primary feedstock. Full article

The production of polyhydroxyalkanoates (PHAs) by Bacillus megaterium using industrial residues, crude glycerol from biodiesel synthesis and rice hull hydrolysate (RHH), as low-cost carbon sources was investigated. The experiments were conducted by shaking flasks at 30 °C and 180 rpm up to 72 h. The extraction of PHA was carried out using sodium hypochlorite to make its recovery more environmentally friendly by avoiding organic solvents (chloroform). The yields of PHA varied depending on the extraction method. A total of 33.3% (w·w⁻¹) (mixing chloroform: sodium hypochlorite) and 52.5% (w·w⁻¹) (sodium hypochlorite only) were obtained using glycerol and glucose as a carbon source, respectively. Preliminary experiments using RHH as a carbon source Indicated a yield of PHA of 11% (w·w⁻¹) (chloroform). The PHA produced had thermal properties, such as transition temperature, similar to the commercial polyhydroxybutyrate (PHB). Full article

Vinasse management in biorefineries bears a burden for sugarcane industries. Despite its high potassium-related fertilizer potential, a series of negative environmental impacts is expected to occur in long-term soil applications of vinasse through fertirrigation. Conversely, a high biodegradable organic content characterizes vinasse as a potential substrate for bioresource and bioenergy recovery from numerous (bio)technological perspectives. This review presents the alternative approaches proposed for sugarcane vinasse management in Brazil, with special attention dedicated to the role of anaerobic digestion as the core conversion step. The suitability of applying phase separation, i.e., the separation of fermentation from methanogenesis in sequential reactors, is discussed in detail. Laboratory and full-scale experiences were considered to discuss the energetic potential of sugarcane vinasse through biogas generation. With a national installed capacity of up to 1603 MW, energy from vinasse could replace half of the coal-derived electricity in Brazil. Meanwhile, investing in vinasse fermentation to obtain soluble organic metabolites could provide more than 10 g L⁻¹ of (iso)butyrate. This is the first review addressing the potential use of sugarcane vinasse in anaerobic biorefineries that discusses applications far beyond conventional biogas production, and encourages the rational use of vinasse as a raw material for bioprocesses, either in short- or long-term scenarios. Full article

The proteomics analysis could contribute to better understand about metabolic pathways in anaerobic digestion community because it still as a “black-box” process. This study aimed to analyze the proteins of the anaerobic co-digestion performed in reactors containing residues from the first and second generation ethanol production. Metaproteomics analysis was carried out for three types of samples: anaerobic sludge without substrate (SI), semi-continuous stirred reactor (s-CSTR) with co-digestion of filter cake, vinasse, and deacetylation liquor (R-CoAD) and s-CSTR with co-digestion of these aforementioned residues adding Fe₃O₄ nanoparticles (R-NP). The R-CoAD reactor achieved 234 NmLCH₄ gVS⁻¹ and 65% of CH₄ in the biogas, while the R-NP reactor reached 2800 NmLCH₄ gVS⁻¹ and 80% of CH₄. The main proteins found were enolase, xylose isomerase, pyruvate phosphate dikinase, with different proportion in each sample, indicating some change in pathways. However, according to those identified proteins, the main metabolic routes involved in the co-digestion was the syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis, with the CH₄ production occurring preferentially via CO₂ reduction. These findings contributed to unravel the anaerobic co-digestion at a micromolecular level, and may select a more appropriate inoculum for biogas production according to that residue, reducing reaction time and increasing productivity. Full article