IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Isolation, selection and characterization of bacterial strains for high organic matter content wastewater treatment
Autor/es:
FLORENCIA A. FICARRA; MARTÍN ESPARIZ; SEBASTIÁN H. LAGORIO; CHRISTIAN MAGNI
Lugar:
Villa Carlos Paz, Córdoba, Argentina
Reunión:
Congreso; VI Congreso Argentino de Microbiología General; 2009
Institución organizadora:
Sociedad Argentina de Microbiología General
Resumen:
In Argentina more than 23% of industries are involved in agro-alimentary production. Together with domestic wastes, this activity is the major contributing factor in water pollution with organic matter. For this reason, large investments are required in wastewater treatments to avoid environment deterioration. Bioaugmentation is the use of selected microbial strains isolated from the environment to improve some of the processes implicated in waste treatment, for example, to degrade xenobiotics or to increase BOD removal. The aim of the present work is to isolate and select bacterial strains able to reduce the organic matter content from industrial wastewater. In particular, we look for exoenzyme-producing bacterial strains. Here we report methods for screening, typification and characterization of the isolations. We followed a classical microbiological approach to isolate strains from a wastewater treatment lagoon of a local factory. We performed several strategies of selection including selective and differential media cultures. We studied their growth profiles, colony morphologies, oxygen relationships and biofilm-forming ability in solid and liquid media. We found that twenty-four isolations were spore-forming, twenty-two showed mobility capabilities, and seven were able to aggregate. We tested their fermentative properties as well as sulfate reducing activities. Twelve strains had a fermentative phenotype and two of the isolations were able to reduce sulfate. We selected four bacterial strains for further analysis. For these strains a 1000 bp region of their 16S ribosomal and their gyrA genes were amplified by PCR and sequenced. This allows us to establish unambiguously that these strains belong to Bacillus genera. In order to distinguish them between Bacilli species we performed RAPDs analysis. This technique allowed us to classify them below species level. With the purpose of finding exoenzymes activities, we analyzed lipase, protease and amylase activities of the cultures. Two of the four strains showed both protease and amylase activities. We complemented the strains characterization with the determination of their nutrient requirements at laboratory scale. Interestingly, our isolations required five times less amount of nitrogen than traditionally recommended for wastewater depuration. This suggested that these strains could be applied to solve low nitrogen operational problems. In conclusion, our results provide insights into isolation and screening methods that contribute to the selection of best candidates for bioaugmentation and improvement of industrial wastewater treatment. gyrA genes were amplified by PCR and sequenced. This allows us to establish unambiguously that these strains belong to Bacillus genera. In order to distinguish them between Bacilli species we performed RAPDs analysis. This technique allowed us to classify them below species level. With the purpose of finding exoenzymes activities, we analyzed lipase, protease and amylase activities of the cultures. Two of the four strains showed both protease and amylase activities. We complemented the strains characterization with the determination of their nutrient requirements at laboratory scale. Interestingly, our isolations required five times less amount of nitrogen than traditionally recommended for wastewater depuration. This suggested that these strains could be applied to solve low nitrogen operational problems. In conclusion, our results provide insights into isolation and screening methods that contribute to the selection of best candidates for bioaugmentation and improvement of industrial wastewater treatment.