Fuente: Microorganisms - Revista científica (MDPI) Microorganisms, Vol. 14, Pages 503: Biosurfactant-Producing Bacteria Isolated from a Microbial Consortium Previously Subjected to Adaptive Laboratory Evolution in Oily Sludge
Microorganisms doi: 10.3390/microorganisms14020503
Authors:
Maria Clara Bessa Souza
Rachel Passos Rezende
Natielle Cachoeira Dotivo
Angelina Moreira de Freitas
Elizama Aguiar-Oliveira
Luiz Carlos Salay
Eric de Lima Silva Marques
Suzana Rodrigues de Moura
Erivelton Santana Ferreira
Luana Silva Ferreira
Henrique Andrade Rabelo Bonfim
Fabiano Lopes Thompson
Bianca Mendes Maciel
João Carlos Teixeira Dias

Microbial bioprospecting in contaminated environments is a promising strategy for identifying biosurfactant-producing bacteria; however, translating environmentally adapted strains into predictable cultivation processes remains challenging. In this study, a microbial consortium subjected to long-term evolutionary laboratory adaptation in oily sludge was investigated to evaluate strain-specific phenotypic responses related to biosurfactant production. Phylogenetic analysis based on 16S rDNA sequencing identified three taxonomically distant isolates: Faucicola sp. strain BS5C, Pseudomonas sp. strain BS16B, and Enterobacter sp. BS14MR. Biosurfactant production was evaluated using a sequential Design of Experiments (DOE) approach, including fractional factorial and central composite rotatable designs, with the emulsification index (E24) used as a semi-quantitative response variable. Initial screening revealed a statistically significant negative effect (p < 0.10) of high dextrose concentrations for all isolates. Strain-specific differences in model adequacy were observed, with a statistically adequate quadratic model obtained for Pseudomonas sp. BS16B (R2 = 0.8658, p = 0.0225), whereas the other isolates showed significant lack of fit (p < 0.05). ATR-FTIR analysis revealed spectral profiles consistent with lipopeptide-like compounds. Overall, these results indicate that isolates derived from the same long-term adapted system may differ substantially in process predictability, suggesting that productivity-based screening alone may be insufficient for selecting robust strains.