Search Results (79)

In accordance with growing environmental pressures and the demand for sustainable industrial practices, membrane technologies have emerged as key enablers for increasing efficiency, reducing emissions, and supporting circular processes across multiple sectors. This review focuses on the integration among microalgae-based systems, offering innovative and sustainable solutions for biomass production, carbon capture, and industrial wastewater treatment. In cultivation, membrane photobioreactors (MPBRs) have demonstrated biomass productivity up to nine times greater than that of conventional systems and significant reductions in water (above 75%) and energy (approximately 0.75 kWh/m³) footprints. For carbon capture, hollow fiber membranes and hybrid configurations increase CO₂ transfer rates by up to 300%, achieving utilization efficiencies above 85%. Coupling membrane systems with industrial effluents has enabled nutrient removal efficiencies of up to 97% for nitrogen and 93% for phosphorus, contributing to environmental remediation and resource recovery. This review also highlights recent innovations, such as self-forming dynamic membranes, magnetically induced vibration systems, antifouling surface modifications, and advanced control strategies that optimize process performance and energy use. These advancements position membrane-based microalgae systems as promising platforms for carbon-neutral biorefineries and sustainable industrial operations, particularly in the oil and gas, mining, and environmental technology sectors, which are aligned with global climate goals and the UN Sustainable Development Goals (SDGs). Full article

The effective use of biowaste resources becomes crucial for the development of bioprocessing alternatives to current oil- and chemical-based value chains. Targeting the development of multi-product biorefinery approaches benefits the viability and profitability of these process schemes. Certain oleaginous microorganisms, such as oleaginous red yeast, can co-produce industrially relevant bio-based products. This work aims to explore the use of industrial and urban waste as cost-effective feedstock for producing microbial oil and carotenoids using Rhodosporidium toruloides. The soluble fraction, resulting from homogenization, crushing, and centrifugation of discarded vegetable waste, was used as substrate under a pulse-feeding strategy with a concentrated enzymatic hydrolysate from municipal forestry residue obtained after steam explosion pretreatment (190 °C, 10 min, and 40 mg H₂SO₄/g residue). Additionally, the initial nutrient content was investigated to enhance process productivity values. The promising results of these cultivation strategies yield a final cell concentration of 36.4–55.5 g/L dry cell weight (DCW), with an intracellular lipid content of up to 42–45% (w/w) and 665–736 µg/g DCW of carotenoids. These results demonstrate the potential for optimizing the use of waste resources to provide effective alternative uses to current biowaste management practices, also contributing to the market of industrially relevant products with lower environmental impacts. Full article

Oilseed cakes, by-products of oil extraction, represent an underutilized resource with significant potential for sustainable food and pharmaceutical applications. This comprehensive review examines the valorization strategies for oilseed cakes, focusing on their rich protein (up to 56%) and fiber (up to 66%) content. We analyze both conventional and innovative extraction methods, highlighting the advantages of ultrasound-assisted (96.64% phenolic compound yield), enzymatic (82–83% protein recovery), and subcritical water extraction techniques in improving efficiency while reducing environmental impact. This review demonstrates diverse applications of oilseed cake components from gluten-free bakery products and plant-based meat alternatives to advanced nanoencapsulation systems for bioactive compounds. Each major oilseed type (soybean, rapeseed, sunflower and flaxseed) exhibits unique nutritional and functional properties that can be optimized through appropriate processing. Despite technological advances, challenges remain in scaling extraction methods and balancing yield with functionality. This paper identifies key research directions, including the development of integrated biorefinery approaches and the further exploration of health-promoting peptides and fibers. By addressing these challenges, oilseed cakes can play a crucial role in sustainable food systems and the circular economy, transforming agricultural by-products into high-value ingredients while reducing waste. Full article

Polyurethane (PU) is widely used due to its attractive properties, but the shift to a low-carbon economy necessitates alternative, renewable feedstocks for its production. This review examines the synthesis, properties, and sustainability of bio-based PU materials, focusing on renewable resources such as lignin, vegetable oils, and polysaccharides. It discusses recent advances in bio-based polyols, their incorporation into PU formulations, and the use of bio-fillers like chitin and nanocellulose to improve mechanical, thermal, and biocompatibility properties. Despite promising material performance, challenges related to large-scale production, economic feasibility, and recycling technologies are highlighted. The paper also reviews life cycle assessment (LCA) studies, revealing the complex and context-dependent environmental benefits of bio-based PU materials. These studies indicate that while bio-based PU materials generally reduce greenhouse gas emissions and non-renewable energy use, their environmental performance varies depending on feedstock and formulation. The paper identifies key areas for future research, including improving biorefinery processes, optimizing crosslinker performance, and advancing recycling methods to unlock the full environmental and economic potential of bio-based PU in commercial applications. Full article

Concerns about sustainable energy sources arise due to the non-renewable nature of petroleum. Escalating demand for fossil fuels and price inflation negatively impact the energy security and economy of a country. The generation and usage of biofuel could be suggested as a sustainable alternative to fossil fuels. Several studies have investigated the potential of using edible crops for biofuel production. However, the usage of algae as suitable feedstock is currently being promoted due to its ability to withstand adverse environmental conditions, capacity to generate more oil per area, and potential to mitigate energy crises and climate change with no detrimental impact on the environment and food supply. Furthermore, the biorefinery approach in algae-based biofuel production controls the economy of algal cultivation. Hence, this article critically reviews different cultivation systems of algae with critical parameters including harvesting methods, intended algae-based biofuels with relevant processing techniques, other applications of valorized algal biomass, merits and demerits, and limitations and challenges in algae-based biofuel production. Full article

Volatile fatty acids (VFAs) are inevitable intermediates of biogas production during the anaerobic digestion of organic matter. The excessive accumulation of VFAs leads to a pH drop and the strong inhibition of methanogenesis. On the other hand, VFAs are useful commodities with different applications, and their fermentative production may compete with traditional production methods based on oil derivatives. The fermentation methods have commonalities with the biorefinery concept. The present review considers the methods of VFA fermentative production together with competitive simultaneous biogas and hydrogen production. Methods of the enhanced production of volatile fatty acids are presented, showing the option of integrated processes of product removal and energy production from the obtained biogas. On the basis of the present review, the following conclusion can be drawn. Volatile fatty acids (formic, acetic, propionic, and butyric ones) are useful commodities with various applications. That is why their targeted production with their desired production rate may shift the aims of the anaerobic digestion toward volatile fatty acids instead of biogas release. On the other hand, VFA production combined with biogas release can make the overall process self-consistent, with energy production sufficient to maintain the target processes using biogas for heating the digestor. The maintenance of optimum VFA concentrations can be accomplished by simultaneous VFA removal from the fermentation broth, thus integrating the product recovery with the maintenance of optimum operation conditions in the digester. The substrate preparation and the operating conditions (organic loading rate and hydraulic retention time) are of crucial importance for the successful fermentation process. Full article

The potential of technical lignins as secondary raw materials is discussed. The characteristics of lignin pyrolysis, with particular emphasis on slow pyrolysis technologies, are briefly summarized. The slow pyrolysis process, which can be self-sustained by burning the coproduced gas, can primarily produce high-quality biochar in significant amounts, to be used as a fuel, as a reductant in metallurgy, and as an adsorbent and catalyst component. Together, significant amounts of bio-oil can be produced, rich in guaiacols, which are commercial and expensive chemicals produced today via petrochemical routes and used in pharmacology, food chemistry, polymer chemistry, etc. Such compounds, or bio-oil itself, can also be converted by hydrodeoxygenation into biofuels. A possible simplified flowsheet for a lignin slow pyrolysis process in the frame of a ligneocellulosics-based biorefinery is proposed. Full article

Challenges in investment decisions for new fuels remain due to uncertain scenarios regarding profitability. There is also a challenge to improve production efficiency and waste utilization, either for biomass or by-products. This study evaluates the economic potential of biomethane production within sugarcane biorefineries through the principles of the circular economy and economic feasibility. To obtain price data for CBios, Brent crude oil, and natural gas, stochastic models based on GBM and Monte Carlo simulations were applied to project prices and assess revenue potential over a 10-year horizon. Price data were incorporated to assess market correlations and revenue scenarios. Key findings reveal that biomethane’s price stability, driven by its strong correlation with oil markets, supports its viability as a renewable energy source, while CBio presents a weak correlation and limited price predictability with present challenges for long-term planning. Economic modeling indicates high investment returns, with IRR values surpassing 35% in conservative scenarios and payback periods from 2 to 6 years. These results highlight biomethane’s potential for energy efficiency, carbon emission reduction, and the creation of new revenue through waste use. We conclude that targeted investments in biomethane infrastructure, coupled with policy and market support, are essential for achieving global sustainability goals. Full article

The use of polyhydroxybutyrate (PHB) can help diminish fossil chemical dependency because it can partially replace petrochemical plastics due to its biodegradability and similar mechanical properties. However, its production costs are high compared with fossil-based plastics. Alternative carbon sources can be used in the fermentation media because they are renewable and low-cost. Vegetable oils are especially attractive due to their high carbon content, contributing to high production rates per gram of substrate. This work aimed to produce PHB from Cupriavidus necator LPB1421 using either corn or soybean oil as the sole carbon source. Urea was the best nitrogen source, enabling a DCW production of 4.35 g/L (corn oil) and 10.4 g/L (soybean oil). After media optimization, the DCW of corn oil reached 22.13 g/L, with 57.46% PHB accumulation (12.71 g PHB/L), whereas soybean oil led to a DCW of 19.83 g/L, with 54.91% PHB accumulation (10.89 g PHB/L). This media composition was employed in a kinetics assay, revealing similar fermentation parameters among both oils and a yield of 0.2118 g PHB/g for corn oil and 0.1815 g PHB/g for soybean oil. These results open the possibility of integrating PHB production with biofuel manufacturing in a bioethanol/biodiesel biorefinery concept. Full article

In recent years, the environmental evaluation of biorefineries has become critical for ensuring sustainable practices in bio-based production systems. This study focuses on the application of the Waste Reduction (WAR) Algorithm to assess the environmental impacts of an Extractive-based Creole-Antillean Avocado Biorefinery located in Northern Colombia, aimed at producing bio-oil, chlorophyll, and biopesticide from avocado pulp, peel, and seed, respectively. The environmental impacts were evaluated using the WAR algorithm, which quantifies the potential environmental impacts (PEI) of different process streams. The following four scenarios were developed: (1) considering only waste, (2) including waste and products, (3) including waste and energy sources, and (4) incorporating waste, products, and energy consumption. This study analyzed global impacts focusing on atmospheric and toxicological categories, with a detailed assessment of the most critical scenario. The results indicated that Scenario 4 had the highest PEI, particularly in the atmospheric and toxicological categories, driven by emissions of volatile organic compounds (VOCs), greenhouse gases (GHGs), and the presence of heavy metals. However, the avocado biorefinery process demonstrated a net reduction in overall environmental impacts, with negative PEI generation rates across all scenarios, suggesting that the biorefinery transforms high-impact substances into products with lower global impact potential. Energy consumption emerged as a significant contributor to environmental impacts, particularly in acidification potential (AP) and Atmospheric Toxicity Potential (ATP). Using natural gas as an energy source had a relatively lower environmental impact compared to coal and liquid fuels, emphasizing the need to optimize energy use in biorefinery design to improve environmental performance. Full article

The annual increase in the world’s population significantly contributes to recent climate change and variability. Therefore, researchers, engineers, and professionals in all fields must integrate sustainability criteria into their decision-making. These criteria aim to minimize the environmental, social, economic, and energy impacts of human activities and industrial processes, helping mitigate climate change. This research focuses on developing scalable technology for the comprehensive use of avocados, adhering to sustainability principles. This work presents the modeling, simulation, and the WEP (Water-Energy-Product) technical evaluation of the process for obtaining bio-oil, chlorophyll, and biopesticide from the Creole-Antillean avocado. For this, the extractive-based biorefinery data related to water, energy, and products are taken from the material balance based on experimental results and process simulation. Then, eight process parameters are calculated, and eleven technical indicators are determined. Later, the extreme technical limitations for every indicator are demarcated, and an evaluation of the performance of the indicators is carried out. Results showed that the process has a high execution in aspects such as fractional water cost (TCF) and energy cost (TCE), as well as solvent reuse during extraction processes (SRI) and production yield, noting that the mentioned indicators are above 80%. In contrast, the metrics related to water management (FWC) and specific energy (ESI) showed the lowest performance. These discoveries support the use of optimization techniques like mass process integration. The energy-related indicators reveal that the process presents both benefits and drawbacks. One of the drawbacks is the energy source due to the high demand for electrical energy in the process, compared to natural gas. The specific energy intensity indicator (ESI) showed an intermediate performance (74%), indicating that the process consumes high energy. This indicator enables us to highlight that we can find energy aspects that require further study; for this reason, it is suitable to say that there is potential to enhance the energy efficiency of the process by applying energy integration methods. Full article

In the current environmental scenario, the proposal of alternatives for petroleum-based products has considerably increased, with the aim of looking for bioproducts with interesting properties such as biodegradability, sustainability and efficiency, among others. In this sense, the role of biolubricants is promising, offering a wide range of possibilities through different methods and operating conditions. Specifically, double transesterification could be a suitable process in a biorefinery context. The aim of this work was to produce a biolubricant through double transesterification with methanol and neopentyl glycol (NPG) under different reaction conditions by using homogeneous catalysis (sodium methoxide). Different catalyst concentrations, among other changes in reaction conditions (temperature ranging between 100 and 140 °C and NPG/FAME ratios between 0.5 and 2), were used, obtaining high conversion values (96%) and a final product with a high viscosity (20.7 cSt), which allows for its use as engine oil (SAE 5W). In conclusion, biodiesel and biolubricant production was feasible through homogeneous catalysis, proving the feasibility of this process at the laboratory scale. Further studies, including the use of different heterogeneous catalysts, as well as the implementation of this process at a semi-industrial scale, are recommended. Full article

Biorefineries are novel biotechnological routes designed to generate sustainable processes from renewable raw materials. The valorization of orange peel waste (OPW) provides high-value products based on their composition. The economic optimization of biorefineries through conceptual design and generation of superstructures based on the analysis of processing units is a topic of great interest. This work aimed to obtain the most profitable biorefinery through economic optimization strategies based on high-value-added products from OPW. Two stages were considered: The first stage consisted of the conceptual design of multiple OPW processing units (production of essential oil, mucic acid, phenolic compounds, biogas, among others). An OPW flow rate of 140 kg/h was selected as the base case. From the stand-alone units, a biorefinery superstructure (second stage) was designed. Finally, the units with the best mass and energy results were selected in order to maximize the net present value (NPV) and obtain an optimal biorefinery configuration. The results evidenced that the production of essential oil and biogas presented the best yields (2.61 mL and 0.028 m³ per kg OPW, respectively). This biorefinery configuration obtained an NPV of −7.7 mUSD from the base case. Through the evaluation of the different superstructure configurations, the combined production of essential oil, biogas, and mucic acid and a scale-up of over 22 times the base case generated the minimum processing scale. Under a Colombian context, the implementation of the biorefineries analyzed are promising since the minimum processing scale contemplated only 8.8% of the OPW production. Efforts to increase yields and decrease capital and operating expenses while keeping environmental impacts low should be pursued. Full article

In this entry, the possibility of the implementation of a biorefinery based on multiple raw materials (from agricultural wastes, vegetable oils, etc.) is covered, pointing out the available technology to interconnect different processes so that the atom economy of the process is as high as possible, reducing the environmental impact and improving the efficiency of the energy or products obtained. For this purpose, this model is based on previous works published in the literature. The role of biorefineries is becoming more and more important in the current environmental scenario, as there is a global concern about different environmental issues such as climate change due to GHG emissions, among others. In this sense, a biorefinery presents several advantages such as the use of natural raw materials or wastes, with high atom economy values (that is, all the products are valorized and not released to the environment). As a consequence, the concept of a biorefinery perfectly fits with the Sustainable Development Goals, contributing to the sustainable growth of different regions or countries, regardless of their stage of development. The aim of this entry is the proposal of a biorefinery based on multiple raw materials, using different technologies such as transesterification to produce both biodiesel and biolubricants, steam reforming to produce hydrogen from glycerol or biogas, hydrothermal carbonization of sewage sludge to produce hydrochar, etc. As a result, these technologies have potential for the possible implementation of this biorefinery at the industrial scale, with high conversion and efficiency for most processes included in this biorefinery. However, there are some challenges like the requirement of the further technological development of certain processes. In conclusion, the proposed biorefinery offers a wide range of possibilities to enhance the production of energy and materials (hydrogen, biodiesel, biolubricants, different biofuels, hydrochar, etc.) through green technologies, being an alternative for petrol-based refineries. Full article

This study aimed to efficiently utilize felled oil palm trunk (OPT) for bioethanol and lactic acid production. OPT was separated into two fractions: oil palm sap (OPS) and OPT fiber. OPS contained substantial amounts of sugars (38–40 g/L) and nitrogen (0.60–0.70 g/L), which can serve as a base medium for bioethanol production. As bioethanol production requires high sugar concentrations, OPS was concentrated, supplemented with OPT fiber, and used for bioethanol production through simultaneous saccharification and fermentation (SSF) by Saccharomyces cerevisiae. Repeated-batch SSF for five cycles efficiently utilized OPT fiber and achieved an average ethanol production of 35–42 g/L in each cycle. To increase the accessibility of the enzyme, OPT fiber was acid-pretreated prior to the SSF process. The combined use of acid-pretreated OPT slurry and concentrated OPS provided the maximum ethanol production of 49.63 ± 1.05 g/L. The fermented broth after ethanol recovery, containing mainly xylose, was used to produce lactic acid at a concentration of 18.85 ± 0.55 g/L. These strategies can greatly contribute to the zero-waste biorefinery of OPT and may also be applicable for the efficient biovalorization of other similar agricultural wastes. Full article