Search

Agroindustrial waste can be valorized towards the obtaining of several products such as pigments, proteins, fibers, and polyphenolic compounds with antioxidant capacity. Orange peel waste is a promising source of polyphenolic compounds such as hesperidin. However, conventional extraction techniques present some environmental limitations such as high solvent consumption and high wastewater generation. Supercritical fluid extraction (SFE) has emerged as a green extraction technique due to the low use of solvent. The aim of this study was to maximize the hesperidin extraction based on theoretical predictions of the operating conditions from empirical thermodynamic models using SFE with carbon dioxide (CO2) as a solvent. The theoretical conditions were validated experimentally on a semi-pilot scale. The extracts were evaluated in terms of hesperidin content, total polyphenol content, and antioxidant capacity. Thermodynamic prediction of the operating conditions showed that the ethanol used as a co-solvent promotes hesperidin extraction. The optimum operating conditions were 25 °C, 80 bar, and a volumetric co-solvent concentration of 10%. The validation of the operating conditions resulted in a final hesperidin concentration of 11.5 ± 0.03 g/kg of orange peel waste. The experimental results were 30.26-times higher using 10% vol of ethanol than the extraction of hesperidin with pure ethanol as a co-solvent. The total polyphenol content and antioxidant capacity resulted in 831.92 ± 40.01 mg Galic acid/100 g orange peel waste, 15.41± 0.91 EC50/mL, and 5.31 ± 0.67 µMolTrox/100 g orange peel. Finally, the prediction of operating conditions from empirical thermodynamic models such as the Peng–Robinson equation of state with some modifications (Stryjek Vera) for solid–gas equilibrium solubility calculations, allows for maximizing the content of the polyphenolic compounds using SFE. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Few valorization pathways have been implemented as alternatives to reduce the orange peel waste (OPW) disposal in landfills. OPW can be a source of income or economic savings in juice production factories since this waste is a potential source of value-added products (e.g., bioactive compounds) and energy vectors (e.g., biogas). Valorization alternatives should be based on (i) orange peel chemical composition, (ii) market analysis, and (iii) availability. Nevertheless, few literature papers have highlighted the chemical composition change caused by the different juice production schemes as a potential opportunity to obtain different value-added products and biorefinery schemes. Thus, the aims of this review paper are related to (i) reviewing different orange fruit processing pathways, (ii) analyzing several OPW chemical compositions reported in the open literature, (iii) providing a summary of OPW extraction pathways for bioactive compounds production, and (iv) evaluating the effect of applying different extraction methods on bioactive compound extraction performance. This review includes a description of the OPW matrix, market insights, packaging, physicochemical characterization, processing technologies, and suggested biorefinery approaches. Finally, different extraction methods for obtaining bioactive compounds from OPW are compared. As a result, the supercritical fluid extraction process has the highest extraction performance and selectivity since this method extracted a high amount of hesperidin (8.18 g/kg OPW db.). In conclusion, OPW is a source of bioactive compounds and valuable products that can be introduced in juice-producing factories to increase product portfolio or economic savings by changing the energy matrix. [ABSTRACT FROM AUTHOR]

The use of chemical fertilizers is essential for agricultural development when soils do not have the nutritional balance required for plants. The continuous use of chemical fertilizers has changed the soil physicochemical and biological properties. Biofertilizer production has been considered as an alternative to reduce chemical fertilizers dependence and the environmental impact. The aim of this study is the evaluation of three technologies for the production of biofertilizers and bioenergy at technical, economic, environmental, and social levels. Ammonium sulfate and digestate-based biofertilizers were obtained via anaerobic digestion; biochar was produced via gasification; and amino acids as plants biostimulants were obtained via protein hydrolysis. Different indicators were calculated for elucidating the sustainability of the processes. Technical, economic, environmental, and social analysis is performed for each of the biorefineries processing stage (complex and stand-alone) without considering the agronomic stage or other value chain links. Scenario 1 presented a positive impact on the economic, environmental, and social aspects since this process has a payback period of 10 years, a carbon footprint of 0.67 kg CO2-eq/kg product, and a potential to generate nine jobs in the Colombian context due to the products portfolio, in contrast with scenario 2 and 3. As conclusion, the integration of biofertilizers and bioenergy in biorefineries have the potential to expand the range of bioproducts and to increase the process sustainability. [ABSTRACT FROM AUTHOR]

This work evaluates the sustainability of small-scale biorefineries as a potential enterprise alternative to be introduced in rural areas based on experimental and simulation data. Four scenarios were evaluated: the first scenario involves the production of guacamole, the second involves the production of animal feed, and the third and fourth scenarios involve the extraction of bioactive compounds and the production of avocado oil or animal feed, respectively. In addition, all scenarios produce biogas and fertilizer. Each of the scenarios were evaluated considering the technical, economic, environmental, and social aspects. As a main result, the first scenario showed the lowest operating and investment costs, as well as the lowest economic profitability (profit margin 35%). On the other hand, the third and fourth scenarios present the highest investment and operating expenses (OpEx USD 6.2 million per year and CapEx USD 1.0 million), but their profit margins are in the 60–70% range. Furthermore, a life-cycle assessment (LCA) was carried out and allows inferring that the transformer link presents the highest environmental impact of the entire value chain and that the carbon footprint for all scenarios ranges between 1.01–2.41 kg C O 2 eq per kg avocado. Similarly, the social impact methodology shows that the proposed scenarios do not present any social risk. Thus, the biorefinery for animal feed, bioactive compounds, biogas, and fertilizer was selected as the best option to be implemented in Caldas. [ABSTRACT FROM AUTHOR]

Lignocellulosic materials are usually processed toward C5 and C6 corresponding sugars. Trifluoroacetic acid (TFA) is a pretreatment method to solubilize hemicellulose to sugars such xylose without degrading cellulose. However, this pretreatment has not been compared to other processes. Thus, this paper focuses on the techno-economic comparison of the C5–C6 production of C5–C6 as raw materials platforms using non-centrifuged sugarcane bagasse (NCSB) and Pinus patula wood chips (PP). Hydrolysates using TFA 2.5 M as an acid were characterized through HPLC regarding arabinose, galactose glucose, xylose, and mannose sugars. Then, simulations of the processes according to the experimental results were done. The economic assessment was performed, and compared with some common pretreatments. The mass and energy balances of the simulations indicate that the process can be compared with other pretreatments. From the economic perspective, the main operating expenditures (OpEx) are related to raw materials and capital depreciation due to the cost of TFA corrosion issues. The processes showed a CapEx and OpEx of 0.99 MUSD and 6.59 M-USD/year for NCSB, and 0.97 MUSD and 4.37 MUSD/year for PP, considering a small-scale base (1 ton/h). TFA pretreatment is innovative and promising from a techno-economic perspective. [ABSTRACT FROM AUTHOR]

Many plant species characterize tropical forests, and a small fraction has been studied to favor small communities in the food and medicinal fields. The high biodiversity of these regions allows for the proposed alternatives for the valorization of exotic fruits due to their rich content of value-added compounds that benefit human health. This work focuses on improving the nutritional characteristics of the açai production chain by mixing it with noni and araza. As a main result, it was possible to enhance the organoleptic and nutritional characteristics of the fruits after freeze-drying. Then, the seeds and peels of the fruits were valorized by the extraction of bioactive compounds with conventional methods and biogas production by anaerobic digestion. The best compositions of antioxidant capacity and total phenolic compounds were obtained for the extracts based on the araza peel, with values of 116.4 µmol and 276.6 mg of gallic acid per 100 g of raw material, respectively. Regarding biogas production, the anaerobic digestion performance was influenced by the C/N ratio. The experimental results were used as input to simulate small-scale processes. From a technical point of view, the scheme of açai, noni, and araza mixture (Sc. 4) showed the highest mass yields (0.84 kg products/kg RM) and energy requirement (2.54 kW/kg RM). On the other hand, the processing of single açai (Sc. 1) presented the lowest capital costs (1.37 M-USD) and operating costs (0.89 M-USD/year). However, all scenarios showed techno-economic feasibility and demonstrated the potential of these fruits to valorize the açai market. [ABSTRACT FROM AUTHOR]

Featured Application: In the last decade, pretreatment has been considered the core stage in the design of biorefineries. Different schemes could be proposed depending on the design objective, either pretreatments for the feedstock fractionation or pretreatments to obtain a platform product. Nevertheless, many have been described as single-step pretreatments specific to a sub-stream, decreasing the integral valorization performance. This work demonstrates the possibility of sequential pretreatment schemes to maximize the fractionation of lignocellulosic biomass. Through different operational, technical, and economic assessment indicators, the best schemes that would help increase the overall process yields and, certainly, the economic viability are described. Therefore, a good pretreatment design will affect the upstream and downstream performance of the biorefineries. Pretreatment technologies are proposed to break the crosslinked biomass matrix and facilitate bioconversion processes or chemical agent attacks in reaction schemes. However, most of the pretreatments are studied in single-step schemes, limiting the integral valorization of the feedstock composition. Therefore, sequential pretreatments could maximize this valorization by isolating more biomass fractions or removing unwanted compounds. This work focuses on proposing and assessing different sequential pretreatments for the isolation of lignocellulosic fractions. After a pretreatment screening, ten technical and economic indicators were assessed through a heuristic analysis. Data from the literature were used to evaluate five operational indicators and as the specification of processing units in simulation schemes to also evaluate five techno-energetic and economic indicators. As a main result, it was concluded that the sequential pretreatments of dilute acid (DA) with wet air oxidation (WAO) could be the most optimal for cellulose isolation, steam explosion (SE) with DA for hemicellulose fractionation, and DA with kraft process for lignin solubilization. Additionally, the DA and WAO sequence may be the most efficient in biorefinery designs since it maximizes biomass fractionation, producing two hydrolyzed liquors, one rich in sugars and the other in soluble lignin, as well as a cellulose-rich solid. [ABSTRACT FROM AUTHOR]

Biorefineries have been defined as complex systems where biomass is integrally processed to obtain value-added products and energy vectors, involving recent research advances, technological trends, and sustainable practices. These facilities are evolving since new pathways and challenges for biomass upgrading appear constantly aimed at increasing process sustainability. Nevertheless, few literature papers summarize how these new trends can improve biorefinery sustainability and boost the transition to renewable resources. This paper reviews several challenges and future perspectives before biorefinery implementation at the industrial level. Challenges related to waste stream valorization, multifeedstock use, biorefinery energy matrix diversification, and new products based on new biomass conversion pathways are reviewed. Thus, this paper provides an overview of the most recent trends and perspectives for improving biorefinery sustainability based on waste stream minimization, integral use of raw materials, and high-value bio-based compound production. A case study is discussed to show how integral biomass upgrading can improve the economic and environmental performance of existing processing facilities. Carbon dioxide capture, storage, and conversion, as well as energy matrix diversification, have been identified as the most important aspects of improving the environmental performance of biorefineries (decarbonization). Moreover, multifeedstock biorefineries are profiled as promising options for upgrading several biomass sources in small-scale and modular systems to produce value-added products for boosting rural bioeconomies. Finally, new ways to produce more bio-based products must be proposed to replace existing oil-based ones. [ABSTRACT FROM AUTHOR]

Biorefineries have been profiled as potential alternatives to increase biomass use at the industrial level. However, more efforts are required to improve the sustainability of these facilities through process improvement and product portfolio increase. The catalytic conversion of biomass to chemicals and energy vectors is one of the most studied research lines today. The open literature has described catalytic pathways for producing biofuels and platform molecules using this renewable resource. Nevertheless, few literature reviews have aimed to analyze the role of the catalytic conversion of biomass in biorefineries while considering the following items: (i) biocatalysis, (ii) carbon dioxide conversion, (iii) design based on catalytic biomass upgrading, and (iv) sustainability metrics. This paper reviews several processes where catalysis has been applied to improve yields and conversion to elucidate the potential of this research field to boost biomass implementation in different productive sectors. This paper provides an overview of the catalytic conversion of biomass into a series of biofuels and high-value-added products, involving key topics related to catalyst performance, use, applications, and recent trends. In addition, several research gaps and ideas are highlighted based on previous studies. In conclusion, the catalytic conversion of biomass has the potential to increase biorefineries' sustainability. Nevertheless, more studies focused on (i) the production of new catalysts using renewable resources, (ii) the techno-economic and environmental assessment of processes involving catalysis, and (iii) the influence of involving biomass valorization via heterogeneous catalysis in existing facilities are required to obtain a real understanding of catalytic upgrades' benefits. [ABSTRACT FROM AUTHOR]

Tropical forests are a source of several high-value products that provide livelihood to small communities in different regions. Exotic fruits such as annatto are feedstock sources containing bioactive compounds with important applications in the food industry. Nevertheless, the integral use of annatto for community improvement and the crop's contribution to carbon sequestration in tropical forests have not been analyzed. This paper aims to demonstrate the economic and environmental performance of small-scale alternatives to obtain natural colorants using annatto seed. The extraction of natural colorants (bixin and norbixin) was analyzed using ethanol and NaOH as solvents. The experimental results were used to simulate two scenarios. Scenario one involved bixin production, and scenario two comprised bixin and norbixin production. The economic and environmental assessments were performed considering the life cycle assessment (LCA) methodology based on a Colombian context. The best extraction yield was 72.65 mg g−1 for bixin and 193.82 mg g−1 for norbixin. From a simulation perspective, scenario two showed the best economic performance since a payback period of 3.1 years was obtained. The LCA showed a high CO2 sequestration potential (6.5 kg CO2 eq kg−1 seed) of the annatto crop. Moreover, the solvents used during the colorant extraction proved to be the most environmentally representative. Nevertheless, the CO2 sequestration of the crop continues to exceed the emissions generated by the process. This work demonstrates that the annatto is an alternative for small communities to reach equilibrium between the economic and environmental of the tropical forest. [ABSTRACT FROM AUTHOR]

Biorefinery feasibility is highly influenced by the early design of the best feedstock transformation pathway to obtain value-added products. Pretreatment has been identified as the critical stage in biorefinery design since proper pretreatment influences subsequent reaction, separation, and purification processes. However, many pretreatment analyses have focused on preserving and valorizing six-carbon sugars for future use in bioconversion processes, leaving aside fractions such as hemicellulose and lignin. To date, there has been no pretreatment systematization for the removal of lignocellulosic fractions. This work defines pretreatment efficacy through operational, economic, environmental, and social indicators. Thus, using the data reported in the literature, as well as the results of the simulation schemes, a multi-criteria weighting of the best-performing schemes for the isolation or removal of cellulose, hemicellulose, and lignin was carried out. As a main result, it was concluded that dilute acid is the most effective for cellulose isolation and hemicellulose removal for producing platform products based on six- and five-carbon sugars, respectively. Additionally, the kraft process is the best methodology for lignin removal and its future use in biorefineries. The results of this work help to elucidate a methodological systematization of the pretreatment efficacy in the design of biorefineries as an early feasibility stage considering sustainability aspects. [ABSTRACT FROM AUTHOR]

The use of biomass to obtain value-added products has been a good alternative for reducing their environmental impacts. For this purpose, different studies have been carried out focused on the use of agro-industrial waste. One of the most commonly used raw materials has been bagasse obtained from the processing of sugarcane in high quantities in countries like Brazil, India, China, Thailand, Pakistan, Mexico, Colombia, Indonesia, Philippines, and the United States. From 1 ton of sugarcane, 280 kg of bagasse can be obtained. Sugarcane bagasse (SCB) is a waste that is rich in polysaccharides, which makes it a promising raw material for obtaining products under biorefinery concept. The objective of this work was to analyze from the energetic point of view, different biorefinery schemes in which SCB is employed as a raw material. The design and simulation of the different biorefinery schemes is performed in Aspen Plus software. From this software, it was possible to obtain the different mass and energy balances, which are used in the technical and energetic analysis. Exergy is used as a comparison tool for the energy analysis. These analyses allowed for the selection of the best biorefinery configuration from SCB. [ABSTRACT FROM AUTHOR]