Biofuels Bioproducts & Biorefining-Biofpr最新文献

This study investigated the potential of integrating Parachlorella kessleri biomass with corn stover and tree bark residues as a method for producing bioethanol. The aim was to reduce greenhouse gas emissions, promote environmental sustainability while improving as well food security. The saccharification process involved biomass decrystallization and posthydrolysis, demonstrating the potential use of residual biomass from forests and agriculture. Posthydrolysis resulted in an increase in total reducing sugars in both bark and corn stover. An optimal balance was established to maximize the release of fermentable sugars while minimizing the presence of inhibitors, identifying key factors such as posthydrolysis time for bark and corn stover, the lack of a need for microalgae decrystallization, biomass and microalgae concentration, and the ideal integration point of microalgae in lignocellulosic bioethanol production. Bioethanol production was performed through fermentation assays using Saccharomyces cerevisiae yeast. Despite the higher lignin content of bark, combining it with microalgae provided a higher ethanol yield (33%) than combining microalgae with corn stover (29%). This study is the first to investigate integrating lignocellulosic feedstock and algae biomass in a single bioethanol production system to improve the feasibility of producing advanced renewable biofuels in biorefineries.

In response to climate change, many countries, including Mexico, have committed to reducing their greenhouse gas (GHG) emissions through agreements such as that reached at the Conference of the Parties in Paris in 2015. As a result, Mexico enacted its General Law on Climate Change, which aims to achieve a 50% reduction in emissions by 2050 in comparison with 2000 levels. This represents a significant challenge, especially considering that Mexico has a population of 124 million people and an annual final energy consumption exceeding 5000 PJ, of which 74% comes from hydrocarbons and emits 1.4% of the world's CO₂. This study presents a prospective analysis that estimates the potential impact of biofuels on the entire national energy system using Low Emissions Analysis Platform (LEAP) software. The analysis is structured around three key aspects: the potential applications of biofuels in national demand sectors (agriculture, industry, transport, and residential); the available bioenergy resources, which determine their utilization limits; and the conversion technologies, described in terms of their technical specifications. The results highlight the significant potential of biofuels to reduce national emissions. In a scenario in which renewable energy fully meets the country's energy demand by 2050, biofuels could prevent 26.51% of emissions in comparison with a business-as-usual scenario and cover 22.72% of total national energy demand.

Microbial exopolysaccharides (EPSs) have attracted increasing attention due to their versatile applications across diverse areas. However, large-scale production of EPSs remains challenging due to the high production costs, primarily driven by the use of synthetic carbon sources. This study demonstrates the potential of quinoa stalk hydrolysates as a sustainable alternative for EPS production using a halotolerant bacterial strain that was isolated from a hypersaline environment and termed SU4M. The bacterial isolate was identified through 16S rRNA and gyrB sequencing as a Bacillus swezeyi strain, and was then cultivated in quinoa stalk hydrolysates. The hydrolysates were produced by acid-catalyzed hydrothermal pretreatment using either sulfuric acid or phosphoric acid, followed by enzymatic saccharification. Fermentation experiments conducted in both shake flasks and bioreactors demonstrated that B. swezeyi SU4M utilized glucose from the hydrolysates efficiently, resulting in significantly higher biomass (5.1 ± 0.1 g L⁻¹) and EPS production (1.2 ± <0.1 g L⁻¹) compared to synthetic media (4.3 ± 0.1 g L⁻¹ and 1.1 ± <0.1 g L⁻¹). The kinetic analysis revealed distinct substrate consumption rates and growth patterns, with hydrolysates enhancing EPS yields under single-pulse fed-batch conditions. Advanced characterization techniques, including compositional analysis, Fourier transform infrared (FTIR) spectroscopy, ¹H and ¹H-¹³C heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR), high-performance size-exclusion chromatography (HPSEC), and thermogravimetric analysis (TGA), confirmed that the EPSs derived from hydrolysates were heteropolysaccharides with close structural similarities to those obtained from synthetic media. These findings underscore the potential of quinoa stalk hydrolysates as a biobased alternative to synthetic media as a substrate for EPS production.

Soybean products play an important role in Argentina’s bioeconomy. Greenhouse gas (GHG) emissions from soybean byproducts have been widely assessed to meet sustainability requirements for soybean oil biodiesel, especially by decision makers in the private and public sectors, in response to growing EU and USA market demands. Previous studies have focused primarily on GHG emissions from soybean cultivation and biodiesel production but not on the main byproducts like soy oil and meal. Over the past 15 years, we have participated in these calculations, with methods certified by independent verification bodies. Using real field data, this study presents the total GHG emissions of Argentina’s main soybean products taking into account agriculture, biorefinery, and distribution stages and following EU Renewable Energy Directives I and II (EU RED I and II). The aim of the study was to assess the GHG emissions of Argentina’s soybean-producing chain through an integrated life cycle approach, applying mass and energy allocation methods. The results indicate that GHG emissions from soybean cultivation ranged from 186 to 266 kgCO₂eq per ton of dry soybean, and from 9 to 13 gCO₂eq per MJ of biodiesel. The highest emissions were associated with crop residues, agrochemical production, and fuel use. Over 50% of emissions in soybean farming were attributed to soil N₂O, mainly from crop residues, according to the Greenhouse Gases, Regulated Emissions, and Energy Use in Technologies (GREET) model. Emissions from soybean oil production were estimated at 149.72 kgCO₂eq per ton of oil, consistent with previous studies. For soybean meal production, emissions resulted in 73.57 kgCO₂eq per ton of meal, with 66.1% attributed to natural gas consumption. This study provides a comprehensive evaluation of GHG emissions across the soybean production chain. Its results can support decision making for emission reductions in key stages of the process.

Lignin protects plants from abiotic and biotic stress and plays an important role in plant growth and development. Like an adhesive, lignin is tightly bound to cellulose and hemicellulose and hinders the efficiency of the saccharification of the lignocellulosic biomass used for biofuel production. Sugarcane is an important bioenergy crop, cultivated globally for the production of sugar and bioethanol. Considering the Global Biofuels Alliance (GBA) target to accelerate the global uptake of sustainable biofuels through technology advancements, this review focuses on strategies to boost bioethanol production from sugarcane biomass by amending the lignin content. Bagasse and straw, the two major byproducts of sugarcane, are considered as the main economic sources of bioethanol generation from lignocellulosic biomass, consisting of cellulose, hemicellulose, and lignin. Lignin biosynthesis is accomplished through oxidative coupling of methoxylated dihydroxycinnamyl alcohols such as p-coumaryl, coniferyl, and sinapyl alcohol. These alcohols generate monolignols like p-hydroxyphenyl, guaiacyl, and syringyl, which are incorporated into the lignin polymer. The genes involved in lignin biosynthesis are potential targets for modifying lignin content for improved saccharification efficiency and bioethanol production. Gene editing approaches like RNA interference (RNAi), transcription activator-like effector nuclease (TALEN)-mediated targeted mutagenesis, and clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR–Cas9) have been employed frequently to suppress the expression of key rate-limiting genes involved in lignin biosynthesis. Alteration in lignin composition, by manipulating the syringyl-to-guaiacyl ratio through genome editing approaches, has also proved advantageous for enhancing bioethanol production without compromising agronomic performance.

Energy products derived from the anaerobic fermentation of agroindustrial byproducts can contribute to sustainable development by displacing fossil fuels and lowering greenhouse gas emissions. The byproducts generated in the beer industry (spent grains, spent yeast, and wastewater) could be a sustainable feedstock for anaerobic fermentation, producing biohydrogen and biomethane. This study presents a comparative bibliometric analysis of articles on biohydrogen and biomethane production from anaerobic fermentation of brewery byproducts published over a 10-year period. A systematic literature search identified 45 documents on biohydrogen and 78 documents on biomethane from brewery byproducts published between 2014 and 2023. The increasing number of documents published over that time can be attributed to the demand for suitable waste management options and the need to reduce greenhouse gas emissions. Analysis of the keywords listed by authors revealed that the main focus in biohydrogen production is the ‘biorefinery concept’. In contrast, ‘pretreatment’ and ‘microbial community’ are the key themes driving biomethane production and are important for future research. Biomethane production has been studied more often than biohydrogen production due to biomethane’s higher energy efficiency, denser energy sources, established infrastructure in many countries, and easier storage when compared with hydrogen. Finally, there is a lack of scientific studies of environmental assessment and technoeconomic analysis of biohydrogen and biomethane production from brewery byproducts.

Microalgae are valued in the industrial, commercial, and scientific sectors for their bioactive and functional content, which includes lipids, carotenoids, proteins, and fatty acids. The residual biomass can be converted into biochar, which has significant commercial potential due to its high adsorption capacity and suitability as a support for heterogeneous catalysts, enabling the development of sustainable and cost-effective integrated biorefinery platforms. In this study, Spirulina maxima was cultivated in Zarrouk medium using bubble column photobioreactors. After cultivation, the biomass was harvested by filtration. Phycocyanin pigments were extracted using a sodium buffer solution. The residual biomass was pyrolyzed in a muffle furnace (10 °C min⁻¹, 310 °C, 60 min) to produce biochar. This biochar was impregnated with heteropolyacid molybdenum (HPA-Mo) and its catalytic potential was studied in the transesterification reactions of macaw palm oil. A 2² central composite factorial design was used to assess the effects of impregnation concentration (2–10 mM) and catalyst loading (20–40% w/w). Results showed that low impregnation concentration (2 mM) and biochar catalyst loadings above 40% (w/w oil) achieved effective conversion into ethyl esters, reaching 70%.

A comprehensive valorization of waste generated from the olive oil manufacturing industry and olive grove pruning was conducted. Anaerobic digestion of the sludge waste from the olive industry was performed in stirred tank reactors under mesophilic conditions to remove volatile solids and to generate biogas. The waste was also treated with an alkali to improve biogas production by reducing the lignin content. The required heating for the anaerobic reactors was supplied by energy valorization of waste biomass from olive prunings through an autothermal process. Good heat transfer in a conical combustor using spouted bed technology was demonstrated by measuring local heat transfer coefficients. Combustion of olive pruning waste in this reactor was highly efficient.

This paper presents a novel technology for converting glycerol, a byproduct of the biodiesel industry, into glycerol carbonate, a high-value bioproduct. The effect of calcination temperature on the synthesis of quaternary Cu-Ni-Mg-Al catalysts (MMO-Cu₁₅Ni₁₅-T_z) and their application in the transesterification reaction was investigated. Glycerol conversion remained largely unaffected by calcination temperature; however, selectivity toward glycerol carbonate was influenced. Physicochemical analyses showed increased crystallinity and spinel phase formation with higher calcination temperatures, resulting in lower oxide dispersion and decreased specific surface area. Nonetheless, the preservation of nanolayer morphology and increased pore diameter maintained high conversion rates at elevated temperatures. X-ray photoelectron spectroscopy (XPS) confirmed Cu²⁺ interactions with the MgAl matrix and the formation of a solid solution. Ultraviolet-visible diffuse reflectance (UV-visible DR) spectroscopy indicated the dominance of octahedrally coordinated Cu²⁺ and spinel phases at the highest temperature. The MMO-Cu₁₅Ni₁₅-T₄₅₀ catalyst exhibited the highest concentration of strong basic sites and the lowest concentration of very strong basic sites. Acid–base characterization suggested that very strong basic sites and abundant acid sites promote glycidol formation by glycerol carbonate decarboxylation. Calcination at 450 °C was identified as optimal, maximizing glycerol carbonate yield while minimizing byproduct formation. This work supports a biorefinery approach aligned with circular economy principles to reduce the environmental impact of biodiesel production through the use of cost-effective catalysts and efficient processes.

Accurate forecasting of solid waste quantities is essential for sustainable waste management planning, yet limited research exists in this area. This study develops a framework to forecast solid waste generation, disposal, and diversion quantities using three machine learning (ML) approaches: artificial neural networks (ANNs), support vector machines (SVMs), and multiple linear regression (MLR) models. The forecasting framework is based on 12 socioeconomic variables, the values of which were derived from publicly available data sources. Projections for 2023 to 2050 were developed considering data preprocessing, training, and testing, to create reliable datasets. Correlation analysis was used to rank predictor and response variables, and statistical tests were conducted to identify heteroscedasticity and linear relationships. A case study was conducted for Canada and four provinces: Alberta (AB), British Columbia (BC), Ontario (ON), and Quebec (QC). The results show that ML algorithms predict solid waste effectively, achieving coefficients of determination (R²) of 99.9% with ANNs and 98.6% with SVMs. The total waste generation for Canada, forecast through ANNs, SVMs, and MLRs, increased by 18.29%, 22.45%, and 22.61%, respectively, in the 28 years from 2023 to 2050. In 2050, the projected values of waste generation using the three methods were 43.67, 45.14, and 44.47 million tonnes, respectively, in Canada. ANN forecasts for 2050 project 7.75 million tonnes in AB, 5.36 in BC, 17.85 in ON, and 8.81 in QC. Waste generation is increasing with increasing population size. The method developed here can be used globally with appropriate data adjustments. The results can help in policy development and decision making.