Isolation and Selection of Sulfur-oxidizing Bacteria for the Treatment of Sulfur-containing Hazardous Wastes

A total of 75 microorganisms were obtained from high-sulfur content environmental samples using different sulfur sources. Fifty-four of them had the ability to oxidize sulfur at 1% (w/v) in liquid culture, however only three of them AZCT-M125-5, AZCT- -M125-6, and AZCT-M125-7 were able to grow autotrophycally using elemental sulfurat concentrations higher than 1 % and up to 9 % (w/v) as energy source. They producemore than 300 mg sulfate/L. Also, these microbial cultures were able to produce sulfate within pH 3 to 7. Analysis based on 16S rRNA gene sequences indicated that microbial cultures AZCT-M125-5 and AZCT-M125-6 were closely related to Acidithiobacillusthiooxidans while identification of AZCT-M125-7 was not possible. According to the results, these three microorganisms can be excellent candidates for the future development of alternative biotechnological processes for the treatment of hazardous wastes containing sulfur

Feather Waste As Petroleum Sorbent: A Study Of Its Structural Biodegradation

Using scanning electron microscopy (SEM), the present study evaluated the biodegradation of chicken feathers during a petroleum hydrocarbon removal process by a defined-mixed culture that pose the simultaneous abilities to remove petroleum hydrocarbons and produce keratinases in liquid culture. Biodegradation treatments were performed in Erlenmeyer flasks containing mineral media, 6% w/v of chicken feathers and 64,800 mg l-1 of petroleum hydrocarbons. Flasks were inoculated with the keratinolytic-mixed culture, which was previously obtained from a petroleum-polluted site, and then incubated at 28ºC, 180 rpm during 21 days. Every 7th day, a sample was collected and fractioned; one fraction was processed to be analyzed by SEM while the residual petroleum-hydrocarbons were extracted from the other fraction and quantified by gas chromatography. Controls without inocula were processed under same conditions. The photomicrographs illustrated the different stages of the feathers’ biodegradation; they are first found intact without degradation while the microorganisms from the mixed culture appear only in the supernatants. After the 7th day a remarkable colonization of the feathers begins to be observed, along with a considerable degradation observed after the 14th day of incubation