Safety in our lab and project is important to consider, especially since is the first time that some organisms we are using will be used in the lab. We have divided our safety section in two sub-sections. The first one, safe lab work, is about the measures and protocols we took in our lab to ensure safety against hazardous situations. The other, safe project design, is about the safety considerations we took in the design of our project due to its particularities. These precautions and good lab practices are important before, during and after the execution of the project. This will maintain the safety of our lab and the society.
Safe Lab Work
During the summer, we worked on the Laboratory of Molecular Diagnosis and Genetic Manipulation, which is at the installations of the FEMSA Biotechnology Center, located at our institution, Tecnológico de Monterrey, Campus Monterrey.
Since it is the first time Acidithiobacillus ferrooxidans and Chromobacterium violaceum are used on a laboratory inside the Center of Biotechnology, our advisors could only give us general guidance on their use. Two of our team members went to the Laboratory of Geomicrobiology of the Institute of Metallurgy of the Autonomous University of San Luis Potosí and were trained by Dr. Viridiana García Meza, so they could learn how to handle Acidithiobacillus. The risk with this organism lies in the pH of its medium, which is extremely acid. Its handling must be used in an extraction hood and precautions such as using gloves must be taken.
C. violaceum is biosafety level 2 since it can act as an opportunistic pathogen to animals and humans, infecting only immunosuppressed people through skin lesions. Very few cases of this type of infections have been reported. Nevertheless, many of the protocols, such as cell culture and transformation are similar to those from Escherichia coli. Mentoring from Dr. Rodolfo García Contreras, from the Department of Microbiology and Parasitology from the Faculty of Medicine at UNAM was received through phone calls and emails for recommendations of its handling.
Our lab is biosafety level 2, so measurements such as controlled access and decontamination of work surfaces after completion of work. All the rules are established on the Biosafety in Microbiological and Biomedical Laboratories by the Centers for Disease Control and Prevention.
Safe Project Design
Even though one of the organisms we chose as our chassis is listed as biosafety level 2, our project does not present any danger to animals, humans or plants. But, one of the problems in module II, which is the bioleaching by C. violaceum, is the production of cyanide, which is required for the recovery of gold. For this, we designed a cyanide degradation system, where another C. violaceum strain will be modified in order to overexpress cyanide hydratase, a cyanide degradation enzyme.
Due to the complications in fully degrading the cyanide, we must determine the concentration of cyanide left at the end of the process in order to be able to do a proper disposal. This is done according to the NMX-AA-058-SCFI-2001 federal regulation, which establishes the guidelines for the determination of total cyanide in natural, drinking, wastewaters and wastewaters treated. Once this is done, the proper disposal of it must be done, according to the NOM-157-SEMARNAT-2009 federal norm, which establishes the elements and procedures to implement the disposal of mining residues, including cyanide.
Centers for disease control and prevention. (2009). Biosafety in Microbiological and Biomedical Laboratories. (5th Edition ed.). United States: HHS Publication.
Norma Oficial Mexicana NOM-157-SEMARNAT-2009. Diario Oficial de la Federación, 30 de agosto de 2011.
Norma Mexicana NMX-AA-058-SCFI-2001. Diario Oficial de la Federación, 09 de julio de 2009.