Yarrowia lipolytica is a unique, strictly aerobic yeast with the ability to degrade efficiently hydrophobic substrates. In the present work, we evaluated the degrading potential of Yarrowia lipolytica IMUFRJ 50682, isolated from tropical estuarine water in Rio de Janeiro (Brazil), and the possible biomolecules produced during this process. To investigate which crude oil compounds are degraded by Y. lipolytica IMUFRJ 50682, this microorganism was grown in a medium containing Marlim petroleum (19 °API, American Petroleum Institute gravity) at 28 °C and 160 rpm for 5 days. The residual petroleum was submitted to gas chromatograph-mass spectrometric analysis (GC-MS). The chromatographic fingerprints of the residual petroleum were compared with the abiotic control test incubated in the same conditions. Y. lipolytica assimilates high molecular weight hydrocarbons, such as n-alkanes (C11-C19), isoprenoids (pristane and phytane), aromatics with two or three aromatics rings (naphthalene, methylnaphthalenes, dimethylnaphthalenes, trimethylnaphthalenes, phenanthrene, methylphenanthrenes, dimethylphenanthrenes, anthracene). This strain was also capable of consuming more complex hydrocarbons, such as tricyclic terpanes. During this biodegradation, the emulsification index of the culture medium increased significantly, showing that biosurfactant molecules can be produced from this process. Therefore, Y. lipolytica IMUFRJ 50682 showed to be a potential crude oil degrading yeast, which can be used for bioremediation processes and simultaneously produce bioproducts of commercial interest.
Gluten-free bakery products are usually deficient in dietary fiber and inferior sources of protein. Studies that have assessed sensory characterization of products prepared with orange pomace are scarce. This study evaluated the employment of 30% of rice-based pregelatinized composite flours (containing 15, 25 or 35% orange pomace blended with 5% soy protein isolate) on gluten-free biscuits. The target was the investigation of the nutritional profile and consumer’s acceptance of three short dough sweet biscuit samples. Thermoplastic extrusion was an efficient unit operation for the elaboration of a new gluten-free ingredient in which a by-product rich in total dietary fiber and a component with a high level of protein were employed. All pregelatinized composite flours in this study can be labeled as protein sources and can be claimed as high in total dietary fiber content, as well as two biscuit samples that can be labeled as total dietary fiber source. Also, all pregelatinized composite flours and biscuits presented low moisture and water activity, being microbiologically stable to room temperature (25 ± 2 °C). Complementarily, the results of the microbiological evaluations [(coagulase-positiveStaphylococcus, thermotolerant coliform (45 °C) andSalmonellasp. (absence in 25 g)] of the biscuits and their comparison with the Brazilian microbiological standards legislation attested their safety. Concerning the sensory analysis, adults’ results showed that the flavor attribute might be responsible for increasing the overall impression score of a sample. In contrast, children’s results showed that they did not distinguish (p ≥ 0.05) two of three samples of biscuits analyzed.
Bioremediation using microorganisms offers a sustainable approach to addressing hydrocarbon contamination. This study explores biosurfactant production by Yarrowia lipolytica IMUFRJ 50682 during crude oil and asphaltene-free fraction biodegradation in corn steep liquor (CSL)-based media. By evaluating CSL concentrations (5–30 g/L) and combinations with glucose, molasses, and crude oil, this study demonstrates that CSL is an effective nutrient source for supporting microbial growth and biosurfactant production. The highest emulsification index (EI = 73.3%) was achieved with 20 g/L of CSL after 48 h, while media containing mixed carbon sources (glucose and crude oil) enhanced metabolic efficiency, yielding a maximum cell growth of 8 g/L after 150 h. Despite inhibiting cell growth, the asphaltene-free fraction promoted biosurfactant activity, with the EI reaching 35.8% after 264 h. The results emphasize the importance of pH control, with the optimal emulsification being observed at pH ~6. This work highlights the potential of CSL as a cost-effective and sustainable additive, advancing applications in bioremediation and biosurfactant production and contributing to the development of environmentally compatible hydrocarbon degradation strategies.
1 October 2020 in Journal of Food Measurement and Characterization