Isolation and Kinetic Modeling of New Culture from Compost with High Capability of Degrading n-Hexadecane, Focused on Ochrobactrum Oryzae and Paenibacillus Lautus

Nowadays, petroleum pollution is one of the most important environmental challenges in Iran. Some bacteria were isolated for hexadecane degrading from soil, sediment, and sludge; however, there is no report on its isolation from compost. This study was aimed to isolation, molecular identification of novel bacteria with high capability of hexadecane-degrading from compost using enrichments media. The isolated bacteria were identified by PCR with 16S rDNA method and were studied their ability for removing hexadecane in liquid and solid medium. According to results, the isolated bacteria were identified as O.oryzae and P.lautus. In liquid medium, hexadecane concentration decreased from 3000 +/- 1.4 to 366.96 +/- 0.9 mg/l (87.77 +/- 0.2%) by O.oryzae, while the removal percent by P.lautus was 80.89 +/- 1.2% after 33 days. Hexadecane concentration decreased from 30 to 18.09 +/- 0.6 g/kg soil (39.69 +/- 1.1%) during 80 days. The pseudo-first order was the best model for biodegradation by both cultures. Whereas, the kinetic behavior of hexadecane bioremediation was described by first and pseudo-first-order model (r(2) = 0.798). In addition, these isolated bacteria have higher efficiency in hexadecane removal in comparison to the other previously identified bacteria. Moreover, O.oryzae can be used in remediation of petroleum products, especially diesel oil.