The overuse of polymer materials from fossil sources has generated a large volume of waste that causes environmental impacts due to the degradation time. The technological advance has stimulated the search for alternatives that can contribute to sustainability. In this context, the use of biodegradable polymers, that use raw materials from renewable sources stand out because they have that ability to form films and come from abundant sources. Also, in the expectation of optimizing the environmental benefits in this process, it is possible to value the agroindustrial residues, using them as raw material in the synthesis of the polymer, the physical, chemical and mechanical properties of these polymers are important to evaluate the possible applications. The proposal of this chapter is to present current research on renewable sources, including agricultural and industrial residues, to obtain biodegradable polymers, highlighting their properties and possibilities of application.

This study aimed to develop a sustainable bioinput using Streptomyces sp. BEI-18A cultivated in an alternative culture medium (ACM) formulated with winery spent yeast and composting leachate. Actinomycetes were initially isolated from grape waste composting piles and screened for agricultural potential in vitro. Streptomyces sp. BEI-18A was selected for further bioinput development based on its high siderophore production. The ACM formulation was optimized in three steps: (I) determining the optimal concentration of winery spent yeast through mixture design; (II) assessing the effect of composting leachate addition on microbial growth; and (III) establishing the final composition of ACM components. The optimized ACM consisted of 3 g/L spent yeast, 2 g/L sucrose, 1 g/L soybean extract, and 10% (v/v) composting leachate. Cultivation of Streptomyces sp. BEI-18A in this medium resulted in a bioinput containing 7.80 × 10⁷ CFU/mL. Its agricultural potential was validated in pot experiments with wheat and soybean, where application of the bioinput promoted significant improvements in early plant growth, enhancing several phytometric parameters. The results highlight the feasibility of valorizing agro-industrial residues as low-cost substrates for microbial bioinput production. This approach represents a promising strategy to foster sustainability in agriculture while reducing environmental impacts.

The widespread use of synthetic herbicides in agriculture has intensified concerns regarding environmental sustainability and human health, while the evolution of herbicide resistance has outpaced the discovery of new modes of action. Bioherbicides have consequently emerged as a viable alternative, comprising biologically derived compounds capable of suppressing weed growth. This review adopts an integrated perspective on microbially derived bioherbicides, following the active biomolecules from the producing strain and its fermentation conditions to their physiological targets in the plant and to the molecular strategies available for their optimization. Unlike previous reviews, which address these dimensions separately and focus mainly on secondary metabolites, particular emphasis is placed here on enzymes with herbicidal activity and on protein engineering approaches. Based on a structured literature search, 39 original studies were analyzed. Phytopathogenic fungi, mainly Fusarium, Diaporthe, Phoma, Alternaria and Trichoderma, predominate as producing organisms, followed by bacteria of the genera Streptomyces, Pseudomonas and Bacillus, and submerged fermentation using low-cost agro-industrial substrates is the prevailing production strategy. Enzymatic classes such as cutinases, lipases, cellulases, pectinases and proteases act primarily by degrading the cuticle and the cell wall, whereas secondary metabolites frequently target the photosynthetic apparatus, particularly photosystem II; most of these compounds, however, still lack a defined mode of action within established herbicide classification systems. Molecular approaches, including heterologous expression, molecular docking and metabolic engineering, remain comparatively underexplored despite their potential to enhance activity, stability and specificity. Advances in formulation stability, bioprocess scalability, mechanistic characterization and regulatory harmonization are identified as the key requirements to translate these biomolecules into commercially viable products for sustainable weed management. Graphical abstract