Biodiverse Compounds from Angiosperms and Gymnosperms: A Chemical, Nutritional, and Microbiological Approach

Biodiverse composts obtained through composting are widely used in regenerative agriculture due to their ability to improve soil quality, crop growth, and productivity, primarily by promoting beneficial microorganisms. These composts result from the decomposition of mixtures containing nitrogenous and plant biomass. During plant biomass preparation, litter serves as a source of beneficial microorganisms, which transition from endophytes to decomposers. This study tested the hypothesis that the type of litter influences the composition of bacterial and fungal communities in biodiverse composts, thereby affecting species abundance and diversity. To this end, litter from the tree species Handroanthus impetiginosus (Angiosperm-AC) and Pinus elliottii (Gymnosperm-GC) was evaluated in compost preparation, also investigating the impact of litter type on the concentration of macronutrients, chemical parameters (such as organic carbon, cation exchange capacity-CEC; carbon/nitrogen ratio-C/N; organic matter-OM; pH, and humic substances fractions, including humic and fulvic acids), and microbiological quality (assessed by Microbial Biomass Carbon-MBC). The microbial composition of composts prepared with both AC and GC litter was more influenced by the composting method than by plant origin, with bacterial genera such as Thermobacillus (representing 1.27% and 1.23% of the genera present in AC and GC, respectively) and thermotolerant species, adapted to the high temperatures of the thermophilic phase, being notably present. GC litter favored a higher abundance of bacterial (pi = 0.027) and fungal species (pi = 0.042), despite the antimicrobial properties of P. elliottii. In contrast, AC compost accumulated higher levels of macronutrients and OM (39.5%), reflecting the efficacy of specific fungi in decomposition, particularly species from the phyla Chytridiomycota and Zoopagomycota, identified exclusively in this compost. MBC analysis indicated that composts reach optimal efficiency and nutritional quality between 60 and 90 days of maturation, suggesting that this period is the most suitable for leveraging the resident microbiota and producing high-quality composts for agricultural use.