Microbial prospecting for antibiotics and pigments from bacteria isolated from Antarctica

Author(s)

Tiago Rodrigues e Silva

• Document type: Doctoral Thesis
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2018-11-30

Examining board members

Adriana Zerlotti Mercadante; Alexandra Christine Helena Frankland Sawaya; Suzan Pantaroto de Vasconcelos; Lara Durães Sette

• Advisor: Valéria Maia Merzel; Fabiana Fantinatti Garaboginni

Abstract

The Antarctic continent is considered a region with extreme climatic conditions, with low temperatures, high incidence of UV radiation and water deficit. It has a very unique biome, which means that much of its biological heritage can not be found elsewhere on the planet. Under these conditions it is expected to find adapted microorganisms (extremophiles) that can be exploited for the identification of unique and versatile metabolic arsenals with potential biotechnological applications in several areas. The development of recent research in our laboratory with bacteria and fungi in Antarctica allowed the isolation of a large number (around 1200) of microorganisms, many of them possibly indigenous, not yet cataloged or studied for the production of potential bioactive compounds. Based on this repertoire, this study aimed to identify bacterial isolates and discover natural products of biotechnological interest, focusing on antibiotics and pigments for application in the pharmaceutical or cosmetic industry. Thus, a total of 326 bacterial isolates, distributed in 39 different genera, were recovered and identified based on 16S rRNA gene sequencing. Antimicrobial screening revealed fifteen isolates capable of inhibiting the growth of at least one of the indicator strains Escherichia coli, Micrococcus luteus, Staphylococcus aureus, Bacillus subtilis and Candida albicans. A psychrotolerant bacterium, Pseudomonas sp. isolate 99, showed broad antimicrobial spectrum, besides antiproliferative and antiparasitic activity. Regarding pigments, four bacteria were shown to better withstand UV radiation and their pigments were extracted and chemically identified. All selected pigments were identified as carotenoids and exhibited high antioxidant activity and good stability under ultraviolet light exposure. A specific pigment, identified as all-trans-bacterioruberina, proved to be safe in the phototoxicity tests, opening perspectives for further use in the formulation of cosmetics (AU)

• FAPESP's process: 14/17936-1 - Microbial prospecting for antibiotics and pigments from bacteria isolated from Antarctica.
• Grantee: Tiago Rodrigues e Silva
• Support Opportunities: Scholarships in Brazil - Doctorate