Caracterização e potencial biotecnológico de uma tintura botânica produzida pela comunidade tradicional Caiçara de Martim de Sá - Paraty, para redes de cerco flutuante

Abstract

Marine biofouling represents one of the main challenges to coastal activities, especially in artisanal fishing, due to the accumulation of organisms on submerged structures. This study evaluated the biotechnological potential of a traditional dye produced by caiçara fishers from Martim de Sá (Paraty, RJ), made from the bark of a native tree, regarding its influence on organism settlement and the modulation of microbial communities on marine substrates. The dye was reproduced in the laboratory based on fishers’ accounts and applied to polypropylene ropes submerged in Guanabara Bay for up to 21 days, in addition to laboratory tests with Perna perna mussels. Chemical characterization of the dye using UHPLC-HRMS (Ultra-High Performance Liquid Chromatography coupled with High-Resolution Mass Spectrometry) revealed the presence of flavonoids (catechin, epicatechin, and afzelechin) and organic acids (citric and suberic), compounds known for their bioactive properties. The results indicate that the dye does not have a classical anti-fouling effect but may act as a selective modulator of bacterial communities and influence the subsequent stages of fouling establishment. The structure of bacterial communities was assessed by 16S rRNA gene sequencing and revealed that the dye not only physically alters the surface but also biologically influences organisms, potentially through biofilms formed or bioactive compounds released. Limitations include the lack of botanical identification of the plant used and the application of a laboratory-based formulation derived from naturalistic knowledge, which was not tested in its original form in the fishers’ environment. This study highlights the potential for integrating traditional knowledge and applied science in the search for sustainable solutions to marine biofouling.