| Congresso Brasileiro de Microbiologia 2023 | Resumo: 932-2 | ||||
Resumo:Photosynthetic pigments have been one of the most explored elements in cyanobacterial and microalgae, and in an industrial context, as compared to other constituents, they represent the main source of revenue, primarily due to their antioxidant capacity. The phenolic compounds (PC) are also known by this property. The low yield of these molecules has been one of the principal bottlenecks in their commercialization. Among the solutions encountered are the bioprospection of novel strains and the optimization of the product using different growth conditions. In this work, we evaluated the antioxidant activity and determined phycobiliproteins and phenolic compound content in Amazon cyanobacteria. The total PC content (TPC) of the aqueous and organic extracts of the strains Lyngbya sp. CACIAM 07, Desmonostoc sp. CACIAM 45, and Synechococcus sp. CACIAM 66 was determined using the Folin-Ciocalteu method. With the exception of CACIAM 66, ethanol was the best solvent for the extraction of the phenolic compounds, followed by methanol and water, showing values of 22.32 ± 0.12, 39.24 ± 1.58, and 6.66 ± 0.86 for CACIAM 07, 45, and 66, respectively. However, due to the low yield concerning the dry biomass provided by the solvent its potential was reduced, leading to values of 3.97 ± 0.02 (CACIAM 07) and 2.77 ± 0.11 mg GAE g−1 of dry biomass (CACIAM 45). These quantities were considerably lower than those found in the aqueous extract of both strains (10.01 ± 0.89 and 10.66 ± 0.32 mg GAE g−1 of dry biomass, respectively). Given the high TPC value found in the strain Desmonostoc sp. CACIAM 45, the strain was submitted to different growth media to optimize the production of such compounds. The ASM medium offered the most favorable conditions for the biosynthesis of these antioxidant compounds, with a production of 22.45 µg GAE mg−1 dry aqueous extract, followed by CHU-10 (19.28 µg GAE mg−1 dry aqueous extract), BG-11, and AA media. The production of phycobiliproteins was also determined from this material. The CHU-10 and ASM media were responsible for the maximum acquisition of this pigment group. With the exception of phycoerythrin, there were no statistically significant differences between the two media. Both allowed the obtaining of very close concentrations of phycocyanin (59.09 and 59.60 µg mg-1 of dry aqueous extract, respectively) and allophycocyanin (20.52 and 20.76 µg mg-1 of dry aqueous extract, respectively). Phycoerythrin concentration was slightly different. While the CHU-10 medium yielded 59.19 µg of phycoerythrin µg mg-1 of dry aqueous extract, the growth in the ASM medium resulted in a production of 55.8 µg mg-1 of dry aqueous extract. With the exception of AA medium, the ratio of phycocyanin (PC) to phycoerythrin (PE) very little changed with the alteration of the medium, maintaining a proportion near 1:1. Such alterations visibly affected the color of the aqueous extract. The extract obtained from the cells cultivated in AA medium showed a more bluish color while those collected from the other media showed little variation among them. In relation to antioxidant activity, employing the DPPH free radical scavenging assay, Desmonostoc sp. CACIAM 45 exhibited the lowest half maximal inhibitory concentration (IC50) value, (close to 1.25 mg mL-1). In general, all the cyanobacteria here showed promising features for cosmetic application or in the food industry. Further investigations are ongoing to ensure its safe use. Palavras-chave: Cyanobacteria, Biotechnology, Pigments, Phenolic compounds, Optimization Agência de fomento:Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Fundação Amazônia Paraense de Amparo a Estudos e Pesquisas (FAPESPA) e Pró-Reitoria de Inclusão e Pertencimento da Universidade de São Paulo | |||||