Chitin is one of the most abundant biopolymers in nature and is found mainly in the exoskeletons of crustaceans and insects, in the cell walls of fungi, and in some species of mollusks. Chitosan is a derivative of chitin; it is much more accessible and has a broader range of applications, including improving the quality of materials such as films, plastics, and concrete. The rheological properties of chitin and chitosan refer to their behavior against deformation and flow and their ability to resist structural changes under mechanical stress conditions. These properties are fundamental in applications where the aim is to control the texture, viscosity, and handling of these biopolymers. Three types of methods for the extraction of chitin and chitosan can be classified: the first is the chemical method, which presents high yields but uses reagents that generate toxic residues; the second is the biological method, which takes advantage of chemical reactions of microorganisms but in some cases has low yields compared to chemical extraction; and the third is the enzymatic method, which uses reagents with a low production of toxic residues. However, low extraction yields are also reported. One of the primary sources of chitin and chitosan is the residue of shellfish and crustaceans. However, a new source of obtaining these compounds is the black soldier fly, which has the same yields of biopolymers as shellfish. In addition, this is a residue of the black soldier fly larvae culture, where protein, oil, and biofertilizers are generated by the bioconversion of organic waste. This work proposes the black soldier fly as an alternative source for extracting chitin and chitosan, using organic methodologies that do not generate toxic residues and have high yields. Including these biopolymers in concrete elaboration could have positive results in terms of flexibility, compressive strength, and workability.

Frass generated during the production of black soldier fly larvae is attracting the interest of scientists and horticultural producers because it is a material made from the biotransformation of organic waste, it contains several nutrients that can be used by plants, and it has a biostimulant capacity that has become a recent focus. Thermal composting is a stabilization process that improves the physical and chemical properties of treated wastes, allowing better performance in plants compared to the waste in its fresh state. In this research, thermocomposted frass was evaluated as a germination substrate for kale seeds (Brassica oleracea). To achieve this, the phytotoxicity of increasing concentrations of frass was evaluated by examining the germination of kale seeds, and seedlings were grown for 30 days in germination substrates mixed with 20, 40, 60, 80, and 100% frass under greenhouse conditions. The treatment with 20% frass showed the highest values of seedling height, stem diameter, number of leaves, length and width of the first true leaf and length and width of cotyledons, and reduced the contents of phenols, tannins and antioxidants. However, the content of flavonoids increased compared to the control and the rest of the mixtures.

This study assessed the performance of black soldier fly larvae (BSFL) fed different tomato plant residues (fruit, leaves, and stems) at doses ranging from 100 to 350 mg/larva/day over ten days. Most doses resulted in 100% survival, except for the leaf residue at the highest dose (300 mg/larva/day), which had an 88% survival rate. Growth varied by substrate, with the highest increase observed in larvae-fed tomato fruit, followed by stems and leaves. However, no doses exceeded the control diet regarding biomass accumulation, although fruit tomatoes produced the highest wet biomass (13.71 g). Larvae-fed fruit tomatoes also showed the best performance in waste reduction index (WRI) with 7.56, substrate reduction (SR) of 75%, and a feed conversion rate (FCR) of 3.29. Furthermore, the fruit tomato was the most efficient at converting organic waste into larval biomass. This study demonstrates the potential of using tomato plant residues as a sustainable substrate for BSFL, offering an effective way to manage agricultural waste and produce valuable larval biomass.

Frass generated during the production of black soldier fly larvae is taking the interest of scientists and horticultural producers because it is a material from the biotransformation of organic waste, it has several nutrients that can be used by plants, and its recent focus on its biostimulant capacity. The thermal-composting process is a stabilization that improves physical and chemical properties of treated wastes, allowing better performance in plants compared to its fresh state. In this research, thermocomposted frass was evaluated as a germination substrate for kale seeds (Brassica olerasea). To achieve this, it was evaluated the phytotoxicity in different concentrations on the seeds, and seedlings were grown in a germination substrates mixed with 20, 40, 60, 80 and 100% of frass. The treatment with 20% frass showed the highest values of seedling height, stem diameter, number of leaves, length, and width of first true leaf and length and width of cotyledons, reduced the content of phenols and tannins antioxidants but the content of flavonoids increased compared to the control and the rest of mixtures.

Tagetes erecta L. is an important industrial source of lutein and other phytochemicals with antioxidant, anti-inflammatory, and glucose- and lipid-metabolizing potential. This review analyzes its phytochemical composition, biological mechanisms, potential applications in the prevention of chronic non-communicable diseases, and emerging uses of nanotechnology to enhance biomass and secondary metabolite production. A structured search was conducted in PubMed, Scopus, Web of Science, ScienceDirect, and Google Scholar using terms related to T. erecta, carotenoids, flavonoids, metabolic health, nanoparticles, nanoelicitation, and agro-industrial valorization. The evidence indicates that lutein, zeaxanthin, quercetagetin derivatives, patuletin, quercetin, and phenolic acids can modulate oxidative stress, inflammatory signaling, carbohydrate-digesting enzymes, lipid accumulation, and cell protection. Furthermore, the flowers, leaves, and extraction residues can be used as reducing and stabilizing matrices for the sustainable synthesis of functional nanomaterials. Nanoelicitors, nanofertilizers, and nanoencapsulated systems could stimulate the methylerythritol phosphate pathway, chromoplast differentiation, and the expression of genes related to carotenoid biosynthesis. Taken together, T. erecta represents a promising platform for the development of nutraceuticals, nanobiotechnology, and circular bioeconomy applications; however, phytochemical standardization, clinical validation, mechanistic studies supported by omics sciences, and pilot-scale evaluations are still required.

This study evaluated the effects of thermocomposting followed by vermicomposting on the physicochemical properties of insect frass and its suitability as a germination and growth substrate for kale, tomato, and bell pepper. Vermicomposting improved frass stability by reducing pH, electrical conductivity, carbon content, and the C/N ratio, while increasing total nitrogen, cation exchange capacity, and calcium and magnesium availability, indicating enhanced maturity and nutrient retention. Peat–frass mixtures (20–100%), increased pH from acidic conditions in the control to near neutral in 100% frass and raised electrical conductivity from 0.67 dS m⁻¹ to the highest values in the pure frass treatment. Tomato seedlings exhibited strong tolerance and enhanced growth at all frass proportions, with seedling heights exceeding 33 cm compared with the control. Kale showed optimal growth at 20–60% frass, while 80–100% reduced early development. In bell pepper, emergence declined at high frass proportions, although seedlings grown with ≥40% frass reached heights of approximately 8.3–8.6 cm. Vermicomposted frass also influenced plant metabolism, increasing flavonoid accumulation and modifying antioxidant activity. These findings demonstrate that stabilized frass can serve as a sustainable substrate component, contributing to organic waste valorization and improved seedling production when applied at crop-specific proportions.