Análise genômica e produção de biossurfactantes e/ou bioemulsificantes por três espécies novas dos gêneros Paenibacillus e Psychrobacillus

Abstract

The growing demand for alternatives to synthetic surfactants has driven increased interest in research on biosurfactants and bioemulsifiers due to their ecological and sustainable properties. However, despite their advantages, the production of these compounds, especially on a large scale, still faces challenges related to cost and yield. In this context, the search for new bacterial species capable of producing biosurfactants and bioemulsifiers, combined with the development of strategies to optimize their production, is essential. Furthermore, studying the metabolic pathways involved in the biosynthesis of these compounds allows for the identification of regulatory mechanisms, improvement of production efficiency, and exploration of potential biotechnological applications. Recently, the strains LABEM I01 and LABEM I02 (related to the Paenibacillus genus) and LABEM I03 (related to the Psychrobacillus genus) were isolated by our research group. Therefore, the objectives of this study were: (i) optimize cultivation conditions aiming to enhance the production of biosurfactants and bioemulsifiers; (ii) to genetically and functionally characterize the strains LABEM I01, LABEM I02 (Paenibacillus sp.), and LABEM I03 (Psychrobacillus sp.), determining their genomic diversity, metabolic pathways, and biotechnological potential. Emulsification and drop-collapse tests revealed that all the studied bacteria produce biosurfactants and/or bioemulsifiers. Subsequently, experimental design analyses were conducted to determine the optimal production conditions for biosurfactants and/or bioemulsifiers by LABEM I01, LABEM I02, and LABEM I03. The results indicated that the optimal production temperature for all strains was 34°C. Regarding surface tension, while the biosurfactant and/or bioemulsifier production by LABEM I02 was not influenced by medium salinity and pH, LABEM I01 exhibited higher production at pH 9 and 2% salinity. For LABEM I03, the highest production occurred at pH 5. High-performance liquid chromatography (HPLC) analyses were used to detect the production of surfactin and fengycin, which are biosurfactants from the lipopeptide class, by LABEM I01, LABEM I02, and LABEM I03. The HPLC results showed that LABEM I01 and LABEM I02 produce the lipopeptide fengycin. However, surfactin production was not detected in any of the strains. Regarding the genomic analysis of LABEM I01, LABEM I02, and LABEM I03, Average Nucleotide Identity (ANI) and Digital DNA-DNA Hybridization (dDDH) analyses revealed that LABEM I01 and LABEM I02 represent new species of the Paenibacillus genus, while LABEM I03 represents a new species of the Psychrobacillus genus. All strains harbored genes related to biosurfactant and/or bioemulsifier production. Although genes associated with lipopeptide production were found in LABEM I01 and LABEM I02, LABEM I03 only presented genes linked to exopolysaccharide production. Additionally, the results showed that LABEM I02 possesses genes encoding the production of 2,3-butanediol, a metabolite of significant biotechnological value. Thus, the findings of this study demonstrate that LABEM I01, LABEM I02, and LABEM I03, in addition to their biosurfactant and/or bioemulsifier production capabilities, hold potential applications in various biotechnological processes. Our results particularly highlight the biotechnological relevance of new bacterial species belonging to the Paenibacillus and Psychrobacillus genera.