Comparative Bioremediation of Crude Oil-Amended Tropical Soil Microcosms by Natural Attenuation, Bioaugmentation, or Bioenrichment

Table 1

Growth of selected actinomycetes with different petroleum derivatives as the sole carbon sources and degradation of n-alkanes and total petroleum hydrocarbons (TPHs).

Bacterial strains	Petroleum derivatives^a							Degradation of^b
	C6	C12	C16	DI	GA	TO	NA	n-alkanes	TPH
Rhodococcus sp. DTSB 2.3	−	+	+++	++	+	−	−	3	3
Gordonia rubriperctinta DTSB 2.5	−	++	+++	+	−	−	+	2	3
Rhodococcus sp. DTSB 3.4	−	+	++	++	−	+	+	1	6
G. alkanivorans DTSB 3.6	+	++	++	++	+	−	+	1	5
R. equi DLB 2.6	−	++	++	+++	+	−	+	4	3
Rhodococcus sp. DLB 3.4	−	+	++	+	−	−	−	1	7
G. alkanivorans DLB 3.22	−	+++	+++	+	−	−	+	3	4

^aC6, hexane; C12, dodecane; C16, hexadecane; DI, diesel; GA, gasoline; TO, toluene; NA, naphthalene; (−), no growth observed (+), weak growth; (++), good growth; (+++), very good growth. Data from Alvarez et al. [19];
^bTPH and n-alkanes concentrations were determined using the EPA 8015 C technique [20]. Numbers represent the degradation range presented by the strains: (1) higher than 95%, (2) between 80 and 94%, (3) between 65 and 79%, (4) between 50 and 64%, (5) between 35 and 49%, (6) between 20 and 34%, (7) lower than 19%.