Microbial Prospects for Degradation of Aliphatic Alkanes in a Highly Contaminated Site and the Rain Forest

Alkanes reach the environment by anthropogenic activities and natural processes. The accumulation of alkanes compromises the environmental health and sustainability. Microbial degradation of alkanes contributes remediation. However, most studies have been conducted on highly impacted sites and in temperate ecosystems. Our objective is to isolate alkane-degrading bacteria under various pollution levels and natural ecosystems in Puerto Rico. Samples were collected from soil at a highly contaminated site (Caño Martín Peña) and in a natural ecosystem (El Yunque Rain Forest). Native microbiota was cultivated, as consortium, on rich media for further studies. Alkane-degrading bacteria were isolated from the original samples by aerobic cultivation on mineral media supplemented with specific alkane as sole carbon source. Bacterial prospects were subjected to 16S rDNA sequencing and alkane degradation preference test. Seven aliphatic alkane degradation prospects had been isolated from Caño Martín Peña, including Klebsiella sp. and E. coli strains. These coliform strains were isolated in hexane but were able also to grow in isooctane and hexadecane. Specific substrate preference among them is in process to be determined. At El Yunque rain forest eighteen prospects were isolated with specific substrate preference: hexane (6 isolates), isooctane (5), and hexadecane (7). These strains are in the sequencing process. Aliphatic alkane degradation prospects can be found either in highly contaminated environments such as in natural ecosystems. The difference between them is the rate at which they grow because of the available carbon source. The Neotropical environment has provided novel bacterial prospects for aliphatic alkane degradation.