RESUMEN
Understanding the biochemistry and metabolic pathways of cyanide degradation is necessary to improve the efficacy of cyanide bioremediation processes and industrial requirements. We have isolated and sequenced the genome of a cyanide-degrading Bacillus strain from water in contact with mine tailings from Lima, Peru. This strain was classified as Bacillus safensis based on 16S rRNA gene sequencing and core genome analyses and named B. safensis PER-URP-08. We searched for possible cyanide-degradation enzymes in the genome of this strain and identified a putative cyanide dihydratase (CynD) gene similar to a previously characterized CynD from Bacillus pumilus C1. Sequence analysis of CynD from B. safensis and B. pumilus allow us to identify C-terminal residues that differentiate both CynDs. We then cloned, expressed in Escherichia coli, and purified recombinant CynD from B. safensis PER-URP-08 (CynDPER-URP-08) and showed that in contrast to CynD from B. pumilus C1, this recombinant CynD remains active at up to pH 9. We also showed that oligomerization of CynDPER-URP-08 decreases as a function of increased pH. Finally, we demonstrated that transcripts of CynDPER-URP-08 in B. safensis PER-URP-08 are strongly induced in the presence of cyanide. Our results suggest that the use of B. safensis PER-URP-08 and CynDPER-URP-08 as potential tool for cyanide bioremediation warrants further investigation. IMPORTANCE Despite being of environmental concern around the world due to its toxicity, cyanide continues to be used in many important industrial processes. Thus, searching for cyanide bioremediation methods is a matter of societal concern and must be present on the political agenda of all governments. Here, we report the isolation, genome sequencing and characterization of cyanide degradation capacity of a bacterial strain isolated from an industrial mining site in Peru. We characterize a cyanide dehydratase (CynD) homolog from one of these bacteria, Bacillus safensis PER-URP-08.
Asunto(s)
Bacillus , Proteínas de Escherichia coli , Bacterias/genética , Proteínas de Ciclo Celular/metabolismo , Cianuros/metabolismo , Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Genómica , Hidrolasas , Perú , ARN Ribosómico 16S/genética , ARN Ribosómico 16S/metabolismoRESUMEN
RESUMEN Objetivo: Determinar los valores de la bacteria e indicador fecal Escherichia coli (EC) para aguas de mar de uso seguro y recreacional de la playa Pucusana, Lima. Materiales y Métodos: Las campañas de muestreos se realizaron una vez por semana en el estío del 2019 y fueron procesados en el Laboratorio de Microbiología de la FCB de la Universidad Ricardo Palma mediante colimetría y el método del número más probable (NMP). Resultados: Se comprobó la presencia de EC en todas las muestras analizadas, con valores promedio superiores a 1000 NMP/100 ml. en todas las muestras recogidas. Diez cepas fueron enviadas al INS que determinó que no existe ningún serotipo patogénico, y de acuerdo con regulación peruana la calificación es inaceptable. Conclusiones: Se demuestra la carencia de salubridad ambiental y su relevancia en salud pública. Los factores de riesgo son producidos principalmente por la producción y vertido de las aguas residuales llevados por los colectores al mar y aunque una importante proporción de estas aguas son procesadas en la Planta de Tratamiento de Aguas Residuales PTAR Pucusana se identificaron vertimientos domésticos y municipales que descargan al Pacífico, problemática que debe tener un buen manejo y fiscalización ambiental porque deteriora el medio ambiente sobre todo los mares.
ABSTRACT Objective: To determine the values o f the bacteria and fecal indicator Escherichia coli (EC) for seawater of safe and recreational use of the Pucusana beach, Lima. Materials and Methods: The campaigns of samplings were carried out once a week in the summer of 2019 and were processed in the microbiology laboratory of the Faculty of Biological Sciences (FCB) of the Ricardo Palma University using colimetry and the method of the most probable number (NMP). Results: The presence of EC was verified in all the analyzed samples, with average values higher than 1000 MPN/100 ml. in all collected samples. Conclusions: The lack of environmental health and its relevance in public health is demonstrated. The risk factors are produced mainly by the production and discharge of wastewater. residuals carried by the collectors to the sea and although an important proportion of these waters are processed at the PTAR Pucusana Wastewater Treatment Plant. Domestic and municipal discharges that discharge into the Pacific were identified, a problem that must have good management and environmental control because it deteriorates the environment and the seas.