An attractive alternative to the use of fossil fuels is biodiesel, which can be obtained from a variety of feedstock through different transesterification systems such as ultrasound, microwave, biological, chemical, among others. The efficient and cost-effective biodiesel production depends on several parameters such as free fatty acid content in the feedstock, transesterification reaction efficiency, alcohol:oil ratio, catalysts type, and several parameters during the production process. However, biodiesel production from vegetable oils is under development, causing the final price of biodiesel to be higher than diesel derived from petroleum. An alternative to decrease the production costs will be the use of economical feedstocks and simple production processes. Castor oil is an excellent raw material in terms of price and quality, but especially this non-edible vegetable oil does not have any issues or compromise food security. Recently, the use of castor oil has attracted attention for producing and optimizing biodiesel production, due to high content of ricinoleic fatty acid and the possibility to esterify with only methanol, which assures low production costs. Additionally, biodiesel from castor oil has different advantages over conventional diesel. Some of them are biodegradable, non-toxic, renewable, they can be used alone, low greenhouse gas emission, among others. This review discusses and analyzes different transesterification processes, technologies, as well as different technical aspects during biodiesel production using castor oil as a feedstock.

The current knowledge about the role terrestrial ornamental plants play in constructed wetlands (CWs) has scarcely been evaluated. Likewise, little attention has been given towards the use of new support or fill media for subsurface flow CWs, which may result in the reduction of costs when implemented on a large scale. This study evaluated, during nine months, the effect of three terrestrial ornamental plants and two substrates on the elimination of pollutants in wastewaters by using fill-and-drain vertical subsurface flow CWs (FD-CWs). Sixteen microcosms were used, nine filled with polyethylene terephthalate (PET) and nine with porous river stone (PRS). For each type of substrate, duplicates of microcosms were used, utilizing Anthurium sp., Zantedeschia aethiopica, and Spathiphyllum wallisii as vegetation and two other CWs without vegetation as controls. The environmental conditions, number of flowers, and height of the plants were registered. The results revealed that both substrates in the FD-CWs were efficient in removing pollutants. The average removal of pollutants in systems with vegetation revealed a positive effect on the reduction of the biochemical oxygen demand (55–70%), nitrates (28–44%), phosphates (25–45%), and fecal coliforms (52–65%). Meanwhile, in units without vegetation, the reduction of pollutants was nearly 40–50% less than in those with vegetation. The use of PET as a filling substrate in CWs did not affect the growth and/or the flowering of the species; therefore, its use combined with the species studied in CWs may be replicated in villages with similar wastewater problems. This may represent a reduction in implementation costs when utilizing PET recycled wastes and PRS as substrates in these systems in comparison with the typical substrates used in CWs. More studies are needed to better understand the interactions among these novel support media and the commercial terrestrial ornamental plants.

Essential oils (EOs) and functional extracts (EXs) from cumin (Cuminum cyminum L.), clove (Eugenia caryohyllata), and elecampane (Inula helenium L.) were used as antimicrobial ingredients for the elaboration of edible films. EOs were extracted by hydrodistillation and EXs were obtained by co-hydrodistillation using fatty acid ethyl esters (E₆ and E₇) as co-solvents. Antimicrobial activities of EOs and EXs were evaluated by the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Escherichia coli O157:H7, Salmonella Typhimurium, Bacillus cereus, Staphylococcus aureus, and Listeria monocytogenes (ATCC strains). Based on the MIC/MBC results, EOs and EXs were selected to prepare edible films based on chitosan polymeric structure. The antibacterial effect of the edible films prepared was further evaluated by zone of growth inhibition against the same foodborne pathogens. Results showed that the EOs and EXs with best MIC results were: cumin (750 mg/L), clove (500 mg/L), cumin–E₇ (750 mg/L), clove–E₇ (500 mg/L), and elecampane–E₆ (500 mg/L). Concentrations of 0–2% of EOs and EXs were used to prepare the chitosan plastic films, and the best results in growth inhibition were presented by chitosan films added with clove and clove–E₇ at 2% concentration. The addition of EOs and EXs of clove to chitosan can be an alternative to produce edible films that can be used in food preservation.

The high consumption of fossil fuels has significant environmental implications. An alternative to reduce the use of fossil fuels and develop ecological and economic processes is the bio-refinery approach. In the present study, the authors present the production of biodiesel from castor plants through a biorefinery approach. The process includes sub-processes associated with the integral use of castor plants, such as biodiesel production, oil extraction, fertilizer, and solid biomass production. Economic analyses show that producing only biodiesel is not feasible, but economic indicators (NPV, IRR, and profitability index) show it is much more feasible to establish businesses for the valorization of products and subproducts of castor plants, such as biomass densification. The internal rate return for the second scenario (E2) was 568%, whereas, for the first scenario (E1), it was not possible to obtain a return on investment.

Castor bean (Ricinus Communis) oil has been reported as one of the most important bio-based fuels; however, high amounts of toxic solid residue are generated in the production. This toxicity is due to several molecules, ricin protein being the most studied compound. The inhibition of the ricin protein is essential for eliminating its toxicity. The objective of this study is to predict the possible inhibition process via the interactions between the ricin protein and the flavonoids quercetin (Q) and epigallocatechin gallate (EGCG). The molecular structures of the complexes formed between the ricin protein and flavonoids were studied using quantum-chemical and molecular docking calculations to analyze the type of interaction, active site of the protein, binding energies, and different conformations in the inhibition process. Different methodologies were applied for the molecular structure determination; the best approximation was obtained with B3LYP/6-31G (d,p) theoretical methodology. Mappings of electrostatic potential (MEP) and frontier molecular orbitals were used for the identification of the probable sites of interaction, which were confirmed by molecular docking. The adjustment and alignment of flavonoid groups before and after the interaction, and charge transfer parameters, showed that Q and EGCG act as electron donors inside of the active site in ricin.

Biopolymers can be derived from biological sources, including protein blends with plasticizers, starch, enzymatic synthesis, microorganisms, and algae. They are classified into polynucleotides, polysaccharides, and polypeptides, including polyhydroxyalkanoates, polylactic acid, and thermoplastic starch. Blending polymers with plasticizers and nanoparticles enhances their mechanical, thermal, and barrier properties. Biopolymers have various applications, such as in packaging, textiles, medical devices, cosmetics, agriculture, food products, emulsifiers, construction additives, bioplastics, and biofuels. Some of the advantages of biopolymers include their biodegradability, use of renewable resources, and reduced environmental impact. Nevertheless, certain disadvantages persist, such as high production costs, inadequate waste management systems, material quality loss during recycling, and the limited availability of raw materials. In this context, castor oil has emerged as a promising raw material for biopolymer production, with notable applications in coatings and sealants, and, consequently, bioplastics have become a sustainable and feasible alternative to conventional plastics that aligns with the principles of the circular economy. Moreover, new biopolymers are constantly being developed, and innovative applications are increasingly being explored across industries. The aim of the present review is to analyze the potential of biopolymers as sustainable alternatives to conventional plastics by evaluating their sources, production methods, advantages, limitations, and applications.