In order to evaluate the degradation of fuel oil no. 6 (FO6) in contaminated soil, laboratory-scale bioreactors were set up to study biostimulation, bioaugmentation, and natural attenuation processes. A solution of fertilizers was added in biostimulation and biouagmentation (0.03% N, 0.01% P). To the bioaugmentation process, an enrichment culture of indigenous hydrocarbon-degrading microorganisms was also added once a week. Total aerobic and hydrocarbon-degrading microorganisms were determined by plate count, and total petroleum hydrocarbon (TPH) concentration was determined gravimetrically (EPA method 9071b) every 15 days. After 1 year of study, degradation rate was higher for biostimulation (0.19 g TPH/day), followed by natural attenuation (0.18 g TPH/day) and bioaugmentation (0.16 g TPH/day). TPH showed a change in composition of hydrocarbons, attributed to microbiological activity. Microbial counts of hydrocarbon-degrading microorganisms were on the range of 4–6 log CFU/g soil. Preliminary bacterial identification corresponded to Pseudomonas, Rhodococcus, Actinomyces, and Bacillus strains; randomly amplified polymorphic DNA (RAPD); and denaturing gradient gel electrophoresis (DGGE) analysis demonstrated a large microbial diversity. From the degradation rates, it can be predicted that such limits will be achieved by increasing further 107–117 days of the treatments. Results demonstrated to be efficient on the restoration of contaminated soil, being an alternative to treat soils contaminated with heavy hydrocarbons.
Part of the book: Advances in Bioremediation and Phytoremediation
Candida albicans is an opportunistic dimorphic yeast. This organism is pathogen associated to superficial and systemic infections. Actually, Candida albicans represents an emergent pathogen especially in a patient with some immunity compromises. Added to this, the use of antifungal in an indiscriminate form has increased the resistance of the existing drugs. In this aspect, the nanotechnology generates the possibility of creating new therapeutic agents. Nanoparticles are structures of 1–100 nm with special physicochemical characteristics that allow it to function as therapeutic agents or as carriers of these. Palladium, silver, and gold metallic nanoparticles and iron, titanium, zinc, and copper oxides have been used as growth inhibitors. These nanoparticles have been proved alone or in form of nanocomposites. The objective of this chapter is to describe the state of the art of the use of nanoparticles as inhibitors of the growth of Candida albicans, as well as the most relevant results regarding the mechanisms involved in this inhibition.
Part of the book: Candida Albicans