title: Microbial treatment of sulfur-contaminated industrial wastes.
abstract: The present study evaluated the microbial removal of sulfur from a solid industrial waste in liquid culture under laboratory conditions. The study involved the use of two bacteria Acidithiobacillus ferrooxidans ATCC 53987 and Acidithiobacillus thiooxidans AZCT-M125-5 isolated from a Mexican soil. Experimentation for industrial waste biotreatment was done in liquid culture using 125-mL Erlenmeyer flasks containing 30 mL Starkey modified culture medium and incubated at 30°C during 7 days. The industrial waste was added at different pulp densities (8.25-100% w/v) corresponding to different sulfur contents from 0.7 to 8.63% (w/w). Sulfur-oxidizing activity of the strain AZCT-M125-5 produced 281 and 262 mg/g of sulfate and a sulfur removal of 60% and 45.7% when the pulp density was set at 8.25 and 16.5% (w/v), respectively. In comparison, the strain A. ferrooxidans ATCC 53987 showed a lower sulfur-oxidizing activity with a sulfate production of 25.6 and 12.7 mg/g and a sulfur removal of 6% and 2.5% at the same pulp densities, respectively. Microbial growth was limited by pulp densities higher than 25% (w/v) of industrial waste with minimal sulfur-oxidizing activity and sulfur removal. The rate of sulfur removal for Acidithiobacillus thioxidans AZCT-M125-5 and Acidithiobacillus ferrooxidans ATCC 53987 was 0.185 and 0.0159 mg S g(-1) h(-1) with a pulp density of 16.5% (w/v), respectively. This study demonstrated that Acidithiobacillus thiooxidans AZCT-M125-5 possesses a high sulfur-oxidizing activity, even at high sulfur concentration, which allows the treatment of hazardous materials.
authors.affiliation: a Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada del Instituto Politécnico Nacional , Querétaro , México.
authors.forename: Marlenne
authors.initials: M
authors.lastname: Gómez-Ramírez
authors.forename: Karina
authors.initials: K
authors.lastname: Zarco-Tovar
authors.forename: Jorge
authors.initials: J
authors.lastname: Aburto
authors.forename: Roberto García
authors.initials: RG
authors.lastname: de León
authors.forename: Norma G
authors.initials: NG
authors.lastname: Rojas-Avelizapa
mesh_terms: D042763:Acidithiobacillus / Q000378:metabolism; D013856:Acidithiobacillus thiooxidans / Q000378:metabolism; D001673:Biodegradation, Environmental; D002851:Chromatography, High Pressure Liquid; D007218:Industrial Microbiology; D007220:Industrial Waste; D013455:Sulfur / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D007220:Industrial Waste; D013455:Sulfur