An Efficient Bioemulsifier-Producing <em>Bacillus subtilis</em> UCP 0146 Isolated from Mangrove Sediments

• Main Authors: Patrícia C. V. S. Maia, Vanessa P. Santos, Adriana S. Fereira, Marcos A. C. Luna, Thayse A. L. Silva, Rosileide F. S. Andrade, Galba M. Campos-Takaki
• Format: Article
• Language: English
• Published: MDPI AG 2018-11-01
• Series: Colloids and Interfaces
• Subjects: <i>Bacillus subtilis</i>; bioemulsifier; cassava wastewater; removal pollutant; methylene blue dye
• Online Access: https://www.mdpi.com/2504-5377/2/4/58

In this work, we investigated the potential of <i>Bacillus subtilis</i> UCP 0146 in the bioconversion of a medium containing 100% cassava flour wastewater to obtain a bioemulsifier. The evaluation of the production was carried out by the emulsification index (IE₂₄) and the surface tension (ST). The ionic charge, stability (temperature, salinity, and pH measured by IE₂₄ and viscosity), and ability to remove and disperse oil and textile dye were investigated. <i>B. subtilis</i> produced an anionic bioemulsifier in the medium containing 100% cassava wastewater under Condition 4 of the factorial design (inoculum 9% at a temperature of 35 °C and shaken at 100 rpm), and showed a surface tension of 39 mN/m, an IE₂₄ of 95.2%, and a yield of 2.69 g·L⁻¹. The bioemulsifier showed stability at different pH (2–8), temperatures (0–120 °C), and NaCl concentrations, a dispersion oil displacement area (ODA) test of 55.83 cm², and a reduction of the viscosity of the burned engine oil (90.5 Cp). The bioemulsifier was able to remove petroleum (94.4%) and methylene blue azo dye (62.2%). The bioemulsifier and its synthesis from bacteria also emphasizes the role of surfactants in oil remediation.