RESUMO
BACKGROUND: Cadmium (Cd), which is a deadly heavy metal of work-related and environmental concern, has been recognized as a substance that is teratogenic and carcinogenic for humans. Therefore, the need to develop low-cost adsorbents to remove heavy metals from aqueous solution has greatly increased. Adsorbents such as Pantoea agglomerans biomass have been used. AIMS: We investigated the biotechnological potential of Pantoea agglomerans for the biosorption of cadmium from aqueous solution. PATIENTS AND METHODS: Pantoea agglomerans UCP1320 isolated from the effluent of a laundry industry was used to remove cadmium from aqueous solutions. Two approaches were compared using active or thermally inactivated biomass. Three different cadmium concentrations of 1, 10 and 100 ppm were used under constant stirring at temperatures of 25°C and 35°C as was pH of 3.0, 5.0 and 7.0. Variable incubation times of 1, 6, and 24h were also studied. RESULTS: The results showed that the temperature did not influence the uptake of metal by living cells nor by inactive bacterial biomass. However, increasing the pH had a positive effect on removing intermediate concentrations of cadmium. Low concentrations of cadmium were completely removed by both live and inactive biomass. CONCLUSION: Pantoea agglomerans biomass was shown to have a promising performance for the biotechnological removal of cadmium which had been dissolved in aqueous solution.
RESUMO
Almost all oleaginous microorganisms are available for biodiesel production, and for the mechanism of oil accumulation, which is what makes a microbial approach economically competitive. This study investigated the potential that the yeast Candida lipolytica UCP0988, in an anamorphous state, has to produce simultaneously a bioemulsifier and to accumulate lipids using inexpensive and alternative substrates. Cultivation was carried out using waste soybean oil and corn steep liquor in accordance with 2² experimental designs with 1% inoculums (107 cells/mL). The bioemulsifier was produced in the cell-free metabolic liquid in the late exponential phase (96 h), at Assay 4 (corn steep liquor 5% and waste soybean oil 8%), with 6.704 UEA, IE24 of 96.66%, and showed an anionic profile. The emulsion formed consisted of compact small and stable droplets (size 0.2-5 µm), stable at all temperatures, at pH 2 and 4, and 2% salinity, and showed an ability to remove 93.74% of diesel oil from sand. The displacement oil (ODA) showed 45.34 cm² of dispersion (central point of the factorial design). The biomass obtained from Assay 4 was able to accumulate lipids of 0.425 g/g biomass (corresponding to 42.5%), which consisted of Palmitic acid (28.4%), Stearic acid (7.7%), Oleic acid (42.8%), Linoleic acid (19.0%), and γ-Linolenic acid (2.1%). The results showed the ability of C. lipopytica to produce both bioemulsifier and biodiesel using the metabolic conversion of waste soybean oil and corn steep liquor, which are economic renewable sources.
