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Carbonaceous materials derived from biomass have been used as sustainable platforms for the growth of ZnO particles aiming the production of functional composite fillers. Kidney-bean pods were pyrolyzed by applying an experimental design that demonstrates that the specific surface area (SBET) of biochar is improved with increasing pyrolysis temperature combined with a short air-oxidation time. Meanwhile, the graphitization degree and the electrical conductivity (EC) of biochars were negatively affected by increasing the air-oxidation time. The biochar sample with the higher EC and the one with the higher SBET were selected to be functionalized with ZnO particles by a solvothermal methodology, obtaining composites with an EC and SBET properties superior to the ZnO-rGO composite, in addition to a similar antibacterial activity. The developed ZnO-biochar composite structures, which are more ecological and biocompatible than the ZnO composites derived from graphene sheets, can be applied as electrically conductive and active fillers.

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Secondary metabolites (SMs) produced by bacteria from unusual environments can contribute to mitigate some of the health and environmental challenges we face. The knowledge of the diversity and applicability of SMs produced by environmental Gram-negatives is lagging behind that of Gram-positives. Examples include some members of genus Pedobacter that produce nonribosomal peptides active against bacteria listed by the WHO as a priority for R&D of new drugs. Herein, a total of 233 biosynthetic gene clusters (BGCs) were identified in the Pedobacter´s pangenome, which encode the biosynthesis of RiPPs (27%), terpenes (22%), hybrid SMs (17%), PKs (12%), NRPs (9%) and siderophores (6%). Most of BGCs did not have significant hits with MIBiG database, which highlights the novelty of their products. From all species, P. cryoconitis and P. lusitanus encode the highest number and diversity of BGCs. Giving their applicability and ecological roles, the BGCs for the production of siderophores and terpenoids were analysed in detail. It was concluded that some species can be a source of squalene and novel siderophores and carotenoids, which deserve further characterization. This study highlights the genus Pedobacter as a prolific source of SMs, probably with a wide range of biological activities and applications hitherto unknown.

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