CONICET | Buscador de Institutos y Recursos Humanos

Industrial Biotechnology and Applied Microbiology is a semiannual optional course for Chemistry and Biology students at the Faculty of Sciences of the University of Buenos Aires, Argentina. This course is usually attended by 25 students, working in teams of two. The curriculum, composed by 8 lab exercises (8 h-week), includes an oil bioremediation practice which covers a global insight of bioremediation processes: the influence of pollutants on autochthonous microbiota, biodegrader isolation for potential bioaugmentation techniques and biosurfactant production for bioavailability understanding. The experimental steps are the following: a) evaluation of microbial tolerance to pollutants by constructing pristine soil microcosms contaminated with 10%v/w diesel or 5%v/w xylene and b) isolation of degraders and biosufactant production analysis. To check microbial tolerance, microcosms are incubated during one week at room temperature. Samples are collected at 0 h, 4 h and every 48 h for CFU/g soil testing. An initial decrease of total CFU count related to toxicity is noticed, being such pattern generally obtained in each compound. At the end of the experiment, a recovery of the CFU number is observed, evidencing enrichment in biodegraders. Some colonies from the 7th day CFU counting plates are streaked in mineral medium with diesel as sole carbon source. After a week, isolates are inoculated on mineral broth supplemented with diesel to induce biosurfactant production. Surface tension in culture supernatants is measured and an emulsification activity test is carried out to visualize tensioactive effect of bacterial products. Besides the improvement in the good microbiological practices, consequence of the manual work involved in this lab exercise, the students show enthusiasm in different aspects, depending on their own interests. While biology students explore and learn new concepts on solubility, emulsions and bioavailability, chemistry students show curiosity in bacterial behavior and manipulation of microorganisms for environmental benefits.