Biodegradation of mixed hydrocarbon and eicosane by novel Enterococcus mundtii SS1 isolated from automobile service station soil

Abstract

Increasing use of hydrocarbon (HC) in automobiles has made them a threat to the environment. One effective solution to this is biodegradation by indigenous and efficient microorganisms. This study focuses on the biodegradation of mixed real HC i.e., burnt engine oil (BEO) and n-alkane (eicosane) by bacterial isolates from automobile garage soil. Isolates were screened and identified by colony characteristics and 16 s rRNA sequencing. Biodegraded HC was evaluated gravimetrically and by gas chromatography. HC biodegradation can also be correlated with cell growth, biosurfactant production, emulsification index (E24%), pseudo-solubilization, and bacterial cell surface hydrophobicity (CSH). The selected strains were identified as novel Enterococcus mundtii (EM) and well-known Bacillus specie (BS). BEO degradation was 55.15 % and 65.54 % by EM & BS, respectively. Eicosane degradation was 65.17 % and 35.74 % by EM & BS, respectively. These strains were producing biosurfactants i.e., lipoprotein by EM and glycoprotein by BS. E24% with BEO was 43 ± 7 % and 53 ± 10 %; with eicosane was 55 ± 12 % and 48 ± 5 % by EM and BS, respectively. BS showed the highest CSH with BEO and EM with eicosane i.e., 87 % and 82 %, respectively. Results of all the tests collectively support the possibility of efficient bioremediation of BEO by isolates.