Used cooking oils as potential oleochemical feedstock for urban biorefineries - Study case in Bogota, Colombia

FT-MIR-ATR Associated with Chemometrics Methods: A Preliminary Analysis of Deterioration State of Brazil Nut Oil

Brazil nut oil is highly valued in the food, cosmetic, chemical, and pharmaceutical industries, as well as other sectors of the economy. This work aims to use the Fourier transform infrared (FTIR) technique associated with partial least squares regression (PLSR) and principal component analysis (PCA) to demonstrate that these methods can be used in a prior and rapid analysis in quality control. Natural oils were extracted and stored for chemical analysis. PCA presented two groups regarding the state of degradation, subdivided into super-degraded and partially degraded groups in 99.88% of the explained variance. The applied PLS reported an acidity index (AI) prediction model with root mean square error of calibration (RMSEC) = 1.8564, root mean square error of cross-validation (REMSECV) = 4.2641, root mean square error of prediction (RMSEP) = 2.1491, R2cal (calibration correlation coefficient) equal to 0.9679, R2val (validation correlation coefficient) equal to 0.8474, and R2pred (prediction correlation coefficient) equal to 0, 8468. The peroxide index (PI) prediction model showed RMSEC = 0.0005, REMSECV = 0.0016, RMSEP = 0.00079, calibration R2 equal to 0.9670, cross-validation R2 equal to 0.7149, and R2 of prediction equal to 0.9099. The physical-chemical analyses identified that five samples fit in the food sector and the others fit in other sectors of the economy. In this way, the preliminary monitoring of the state of degradation was reported, and the prediction models of the peroxide and acidity indexes in Brazil nut oil for quality control were determined.

Sustainable synthesis of graphene sand composite from waste cooking oil for dye removal

Waste cooking oil (WCO) appears to be a potential carbonaceous source for synthesizing graphene sand composite (GSC) adsorbent in removing pollutants. This study presents a green synthesis method of GSC using WCO as a sustainable carbon source for the synthesis of GSC through the thermal graphitization method. Characterization analysis conducted on GSCWCO verified the successful coating of WCO onto the sand surface and conversion to graphene, which possessed distinct functional groups and features of graphene materials. GSCWCO adsorbent effectiveness in removing Congo Red dye through batch adsorption was studied under the influence of different initial concentrations (20 to 100 mg/L), and the optimum pH (pH 2 to 10), contact time (5 to 240 min), and temperature (25 to 45 °C) were investigated. The GSCWCO showed removal rates of 91.5% achieved at an initial dye concentration of 20 mg L-1, 1.0 g of adsorbent dosage, a temperature of 25 °C, and 150 min of contact time. The GSCWCO exhibited a maximum capacity of 5.52 mg g-1, was well-fitted to the Freundlich isotherm model with an R2 value of 0.989 and had an adsorption mechanism that followed the pseudo-second-order kinetic model. Negative values of enthalpy (ΔH) and Gibbs free energy (ΔG) revealed that CR adsorption onto GSCWCO was a spontaneous and exothermic process. The presence of functional groups on the surface of GSCWCO with such interactions (π-π attractive forces, hydrophobic forces, and hydrogen bonding) was responsible for the anionic dye removal. Regeneration of GSCWCO adsorbent declined after four cycles, possibly due to the chemisorption of dyes with GSC that resulted in inefficient adsorption. Being a waste-to-wealth product, GSCWCO possessed great potential to be used for water treatment and simultaneously benefited the environment through the effort to reduce the excessive discharge of WCO.

Biorefinery development, techno-economic evaluation and environmental impact analysis for the conversion of the organic fraction of municipal solid waste into succinic acid and value-added fractions

The organic fraction of municipal solid waste (OFMSW) was used for biorefinery development within a circular bioeconomy context towards extraction of lipids/fats and proteins with 100% and 68% recovery yields, respectively, as well as succinic acid (SA) production. A nutrient-rich hydrolysate (89.1 g/L sugars) produced using crude enzymes derived via solid state fermentation of Aspergillus awamori, was employed in Actinobacillus succinogenes fermentation leading to 31.7 g_SA/L with 0.68 g/g yield and 0.67 g/L/h productivity. The SA minimum selling price ($1.13-2.39/kg_SA) considering 60,000 t_SA/year production varied depending on co-product market prices and OFMSW management fees. The biorefinery using 1000 kg OFMSW contributes 35% lower CO₂ emissions than conventional processes for the production of 105 kg vegetable oil, 87 kg vegetable protein and 206.4 kg fossil-SA considering also the CO₂ emissions due to OFMSW landfilling. The proposed OFMSW biorefinery leads to cost-competitive SA production with lower CO₂ emissions for OFMSW treatment.

Algal biomass valorisation to high-value chemicals and bioproducts: Recent advances, opportunities and challenges

Algae are considered promising biomass resources for biofuel production. However, some arguments doubt the economical and energetical feasibility of algal cultivation, harvesting, and conversion processes. Beyond biofuel, value-added bioproducts can be generated via algae conversion, which would enhance the economic feasibility of algal biorefineries. This review primarily focuses on valuable chemical and bioproduct production from algae. The methods for effective recovery of valuable algae components, and their applications are summarized. The potential routes for the conversion of lipids, carbohydrates, and proteins to valuable chemicals and bioproducts are assessed from recent studies. In addition, this review proposes the following challenges for future algal biorefineries: (1) utilization of naturally grown algae instead of cultivated algae; (2) fractionation of algae to individual components towards high-selectivity products; (3) avoidance of humin formation from algal carbohydrate conversion; (4) development of strategies for algal protein utilisation; and (5) development of efficient processes for commercialization and industrialization.

The conundrum of waste cooking oil: Transforming hazard into energy

Waste cooking oil (WCO) is considered as one of the hazardous wastes because improper disposal of WCO can cause significant environmental problems such as blockages of drains and sewers as well as water or soil pollution. In this review, the physical and chemical properties of WCO are evaluated along with its regulations and policies in different countries to promote WCO refined biofuels. Blended WCO can be an auxiliary fuel for municipal solid waste incinerators while the heat produced is able to form superheated steam and subsequently generate electricity via combined heat and power system. Also, WCO contains high ratio of hydrogen atoms compared to carbon and oxygen atoms, making it able to be catalytically cracked, synthesizing hydrogen gas. WCO-based biodiesel has been traditionally produced by transesterification in order to substitute petroleum-based diesel which has non-degradability as well as non-renewable features. Hence, the potentials of hazardous WCO as a green alternative energy source for electricity generation, hydrogen gas as well as biofuels production (e.g. biodiesel, biogas, biojet fuel) are critically discussed due to its attractive psychochemical properties as well as its economic feasibility. Challenges of the WCO utilization as a source of energy are also reported while highlighting its future prospects.

Glycolipid Biosurfactant Production from Waste Cooking Oils by Yeast: Review of Substrates, Producers and Products

Biosurfactants are a microbially synthesized alternative to synthetic surfactants, one of the most important bulk chemicals. Some yeast species are proven to be exceptional biosurfactant producers, while others are emerging producers. A set of factors affects the type, amount, and properties of the biosurfactant produced, as well as the environmental impact and costs of biosurfactant’s production. Exploring waste cooking oil as a substrate for biosurfactants’ production serves as an effective cost-cutting strategy, yet it has some limitations. This review explores the existing knowledge on utilizing waste cooking oil as a feedstock to produce glycolipid biosurfactants by yeast. The review focuses specifically on the differences created by using raw cooking oil or waste cooking oil as the substrate on the ability of various yeast species to synthesize sophorolipids, rhamnolipids, mannosylerythritol lipids, and other glycolipids and the substrate’s impact on the composition, properties, and limitations in the application of biosurfactants.

Green chemicals from used cooking oils: Trends, challenges, and opportunities

Food waste reduction is fundamental for sustainable development and pursuing this goal, recycling and the valorization of used cooking oil (UCO) can play a major contribution. Although it has been traditionally used for biofuel production, the oleochemical potential of UCOs is vast. UCOs can be used as feedstock for a large variety of value-added green chemicals including plasticizers, binders, epoxides, surfactants, lubricants, polymers, biomaterials, and different building blocks. Thus, UCO transformation into functional chemicals can bring long-term stability to the supply chain, avoiding the current dependence on commodity products. In this regard, this work describes some of the potential benefits of using UCOs as feedstock in oleochemical biorefineries. In addition, some of the most recent investigations on the valorization of UCOs other than biofuel are presented. Finally, major challenges and future directions are discussed.

Green Cities and Waste Management: The Restaurant Industry

“Green Cities” are cities with the ultimate goal of achieving a net zero-carbon footprint in energy, transportation, architecture, and the activity cost chain of businesses. These cities define the future of our planet by emphasizing the efficient use of resources and the well-being of communities. This study focuses on “Green Cities” and the restaurant industry. It examines the beliefs of restaurant owners/managers on the positive impact of sustainability practices on financial situation, reputation, and attraction of customers, and the relationship between such beliefs and the extent of engagement in sustainability practices. The research also explores whether declaring a city “Green” enhances the sustainability practices in that city. The results indicate that the restaurant owners/managers in all three studied cities strongly believe that sustainability practices enhance the financial performance, reputation of the restaurant, and attraction of customers, yet a significant percentage of the wastes and by-products of the operations of the studied restaurants are discarded. In addition, the results of the study show no significant impact on sustainability practices in the studied restaurants for the declared “Green” cities of Providence (U.S.) and Nancy (France) versus the city of Springfield (U.S.). The study concludes by highlighting the potential reasons underlying the lack of sustainability practices in the restaurant industry and proposes recommendations that can enhance such practices in this industry.

Improving the recycling technology of waste cooking oils: Chemical fingerprint as tool for non-biodiesel application

Samples of sunflower Waste Cooking Oils (WCOs) subjected to several cycles of frying were treated with water under four different combinations of temperature and pH. Several aspects of the chemical composition of edible, non-treated and processed samples was determined by three different analytic techniques: headspace Solid-Phase Microextraction (HS-SPME) coupled with gas-chromatography (GC), ¹H NMR spectroscopy and ESI-MS spectrometry. Thus, a characteristic chemical fingerprint of each sample was derived and proposed as useful set of tools for the optimization of recycling of WCOs. On the basis of the presented results, a mini-plant for the production of bio-lubricants and bio-solvents with a circular economy approach was designed and herein described.