Biosurfactant and bioemulsifier as promising molecules produced by Mucor hiemalis isolated from Caatinga soil

BACKGROUND: The present study describes the production of biosurfactant (BS) and emulsifier (BE) by the filamentous fungus Mucor hiemalis UCP 0039, as well as the characterization and stability of the both biomolecules for environmental or industrial applications. RESULTS: Biosurfactants and bioemulsifiers are amphiphilic compounds and are produced as extracellular molecules. The results showed that bioproduct obtained by shaker condition reduced the water surface tension of 72 to 32 mN/m and reached an emulsification index of 96%, while the static cultivation resulted in a biomolecule with a surface tension of 40 mN/m and an emulsification index of 96%, suggesting the production of a biosurfactant and bioemulsifier, respectively. The compounds showed glycolipid nature but the biosurfactant presented cationic charge, while the bioemulsifier, anionic charge. Thus, the results confirmed that M. hiemalis produced two distinct biomolecules under different parameters and in the same culture medium. CONCLUSIONS: It is the first time that biosurfactant and emulsifier production has been described in the same medium and under different physical conditions by Mucor hiemalis. Both biomolecules showed thermal stability, as well as have significant effect on the viscosity of hydrophobic compounds, indicating the excellent potential for environmental safety or industrial applications to improve the efficiency of sustainable and economic technologies.

Conversion of renewable substrates for biosurfactant production by Rhizopus arrhizus UCP 1607 and enhancing the removal of diesel oil from marine soil

BACKGROUND: The use of agro-industrial wastes to produce high value-added biomolecules such as biosurfactants is a promising approach for lowering the total costs of production. This study aimed to produce biosurfactants using Rhizopus arrhizus UCP 1607, with crude glycerol (CG) and corn steep liquor (CSL) as substrates. In addition, the biomolecule was characterized, and its efficiency in removing petroderivatives from marine soil was investigated. RESULTS: A 22 factorial design was applied, and the best condition for producing the biosurfactant was determined in assay 4 (3% CG and 5% CSL). The biosurfactant reduced the surface tension of water from 72 to 28.8 mN/m and produced a yield of 1.74 g/L. The preliminary biochemical characterization showed that the biosurfactant consisted of proteins (38.0%), carbohydrates (35.4%), and lipids (5.5%). The compounds presented an anionic character, nontoxicity, and great stability for all conditions tested. The biomolecule displayed great ability in dispersing hydrophobic substrates in water, thereby resulting in 53.4 cm2 ODA. The best efficiency of the biosurfactant in removing the pollutant diesel oil from marine soil was 79.4%. CONCLUSIONS: This study demonstrated the ability of R. arrhizus UCP1607 to produce a low-cost biosurfactant characterized as a glycoprotein and its potential use in the bioremediation of the hydrophobic diesel oil pollutant in marine soil