How to Valorize Peanut Shells by a Simple Thermal-Catalytic Method

Multicomponent Synthesis of 2,4,5-Trisubstituted Thiazoles Using a Sustainable Carbonaceous Catalyst and Assessment of Its Herbicidal and Antibacterial Potential

Herein, a novel, biocatalyzed, and on-water microwave-assisted multicomponent methodology have been developed for the synthesis of trisubstituted thiazoles (4a-4v). The reaction was catalyzed using a sulfonated peanut shell residue-derived carbonaceous catalyst (SPWB). The developed catalyst was characterized using Fourier transform infrared (FTIR), a Brunauer-Emmett-Teller (BET) surface area analyzer, a field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray (EDX), and a particle size analyzer (PSA). The acidic sites have been established using acid-base back-titration methods. The molecular structures of all the synthesized compounds were validated using FT-IR, 1H NMR, 13C NMR, elemental, and HRMS analyses. Herbicidal potential was evaluated by using Raphanus sativus L. as a model. Furthermore, the antibacterial potential of thiazoles was evaluated against Staphylococcus aureus, Bacillus subtilis, Xanthomonas campestris, Escherichia coli, Micrococcus luteus, and Pseudomonas aeruginosa bacterial strains. The compound 4r displayed improved seed growth inhibition in Raphanus sativus L. versus a commercially available herbicide, i.e., pendimethalin. The antibacterial activity was promising against bacterial strains (MIC: 4-64 μg/mL). The compound 4r was the most potent against P. aeruginosa and S. aureus (MIC: 0.0076 μM) versus standard drug streptomycin (MIC: 0.0138 μM). Moreover, in silico studies performed with the most effective compound 4r against P. aeruginosa revealed its potential binding mode within the protein binding pocket. The biological data revealed compound 4r as a potential candidate for the development of potent herbicidal and antibacterial agents. In a nutshell, this study offers peanut shell biowaste to be a sustainable biomass for heterogeneous acid catalyst preparation and its application in the multicomponent synthesis of bioactive thiazoles, accommodating the concept of sustainable development goals and circular bioeconomy.

Valorization of residual lignocellulosic biomass in South America: a review

Residual lignocellulosic biomass (RLB) is a valuable resource that can help address environmental issues by serving as an alternative to fossil fuels and as a raw material for producing various value-added molecules. To gain a comprehensive understanding of the use of lignocellulosic waste in South America, a review was conducted over the last 4 years. The review focused on energy generation, biofuel production, obtaining platform molecules (such as ethanol, hydroxymethylfurfural, furfural, and levulinic acid), and other materials of interest. The review found that Brazil, Colombia, and Ecuador had the most RLB sources, with sugarcane, oil palm, and rice crop residues being the most prominent. In South America, RLB is used to produce biogas, syngas, hydrogen, bio-oil, biodiesel, torrefied biomass, pellets, and biomass briquettes. The most studied and produced value-added molecule was ethanol, followed by furfural, hydroxymethylfurfural, and levulinic acid. Other applications of interest that have been developed with RLB include obtaining activated carbon and nanomaterials. Significant progress has been made in South America in utilizing RLB, and some countries have been more proactive in regulating its use. However, there is still much to learn about the potential of RLB in each country. This review provides an updated perspective on the typification and valorization of residual biomass in South America and discusses the level of research and technology being applied in the region. This information can be helpful for future research on RLB in South America.