Análise da produção de bioplástico por bactérias isoladas do mangue a partir de fontes alternativas de carbono

Abstract

Polyhydroxybutyrates (PHB) synthesized by mangrove bacteria are accumulated inside the cells in response to environmental stress conditions, aiming to reduce the impacts caused by conventional plastics. For this reason, it is important that through bioprospecting we can study the diversity of bacteria, in order to enable a more detailed and accurate analysis of PHB synthesis by mangrove-isolated bacteria using alternative carbon sources. This study aimed to analyze PHB expression through the bioprospecting of bacteria from the mangroves of Sergipe, with the goal of reducing bioplastic production costs. In this context, the research adopted an experimental approach, allowing for the evaluation of qualitative and quantitative characteristics of samples collected in the mangroves of Praia Formosa in Aracaju, Sergipe, and in the community of Porto das Cabras in Barra dos Coqueiros. The bacteria under study were isolated in Petri dishes and identified through biochemical tests, such as Gram staining, catalase, and urease. In addition, molecular testing was carried out using the PCR technique to identify the species under study. For PHB production and extraction, alternative carbon sources such as sugarcane bagasse and banana and beet peels were used. The characterization of this biopolymer was performed through analysis of the samples using Fourier-transform infrared spectroscopy (FTIR). Among the ten bacterial isolates analyzed, biochemical tests identified approximately six Gram-positive and four Gram-negative bacteria. Furthermore, all samples tested positive and negative, respectively, for catalase and urease. From the molecular test, five samples were sequenced, allowing the identification of three strains of the species Bacillus sp. and two of the species Aeromonas sp. Among the carbon sources used for the synthesis of this biopolymer, banana peel stood out, resulting in the highest PHB concentrations in the bacteria. Overall, all bacteria showed results indicating the presence of PHB, through the vibration of the carbonyl, methyl, and ester groups as observed in the FTIR analysis. It can be concluded that the exploitation of these sources will be extremely important for future prospects related to the various commercial applications of this bioplastic.