## 3 Results
### Growth Attributes of Maize  
Bacterial inoculation significantly improved the roots of inoculated maize crop. Under higher contamination of crude oil, bacterial strains S\({}_{4}\) (PMEL-79), S\({}_{3}\) (PMEL-80), S\({}_{2}\) (PMEL-67), and S\({}_{1}\) (PMEL-63) significantly enhanced the root length of maize, which was recorded \begin{table}
\begin{tabular}{l l l l} \hline \hline
**Isolates** & **Biormediation Assay** & **Exo-Polysaccharide Production** & **Phosphate Solubilization** \\ \hline N\({}_{1}\) & + & \(\uparrow\) & \(\uparrow\) \\ L\({}_{1}\) & ++ & \(\uparrow\) & \(\uparrow\) \\ M\({}_{1}\) & – & \(\downarrow\) & \(\downarrow\) \\ H\({}_{1}\) & – & \(\downarrow\) & \(\downarrow\) \\ H\({}_{2}\) & +++ & \(\uparrow\) & \(\uparrow\) \\ N + O & – & \(\downarrow\) & \(\downarrow\) \\ L + O & – & \(\downarrow\) & \(\downarrow\) \\ M + O & ++ & \(\uparrow\) & \(\uparrow\) \\ H + O & – & \(\downarrow\) & \(\downarrow\) \\ O1 & – & \(\downarrow\) & \(\downarrow\) \\ \hline \hline \end{tabular} N\({}_{1}\) = normal soil; L\({}_{1}\) = low contaminated soil; M\({}_{1}\) = medium contaminated soil; H\({}_{1}\) = high contaminated soil; N + O = normal soil + oil; L + O = low contaminated soil + oil; M + O = medium contaminated soil + oil; H + O = high contaminated soil + oil; + represents the intensity of color and amount of degradation; \(\downarrow\) represents no degradation of crude oil; \(\uparrow\) represents the exopolysaccharide production and phosphate solubilization; \(\downarrow\) represents no exopolysaccharideside production and phosphate solubilisation.  
\end{table} 
Table 3: Results of the bacterial isolate screening for the bioremediation assay, exopolysaccharides production, and phosphate solubilization. as 48.08%, 42.18%, 37.27%, and 30.15% higher than control SOL4, respectively. Of all the strains, the bacterial strain S4 (PML-79) increased the root length more significantly then the other strains, as shown in Figure 3a, reaching a level that was 32.11% higher than control SOL0. The lowest root length was observed in treatment SoL4, where no strain was added and 2000 ppm of crude oil was applied. The bacterial inoculation significantly affected the root length in crude oil concentration; i.e., 1000 and 2000 ppm, respectively. The elongation of shoot of maize was significantly enhanced by bacterial strains S3 (PML-80) and S2 (PML-67), by 16.9% and 20.41% more than the control, respectively. The highest increases in shoot length were observed in strain S4L2, which was 33.94% higher than control SOL0 (Figure 3b). The results show that, overall, the S4 (PML-79), strain performed very well as it increased the root and shoot length of maize under both lower and higher levels of crude oil contamination in soil. In the pot trial, the highest maize fresh biomass was produced in response to inoculation with bacterial strain S4 (PML-79). This extreme rise in the fresh biomass of the maize was 98% compared to the uninoculated control, as shown in Figure 4a. Further bacterial strains that efficiently amplified the maize fresh biomass were S3 (PML-80) and S2 (PML-67), at 43.13% and 28.9% more than the control, respectively. The S4 (PML-79) bacterial strain upheld its consistency in promoting plant growth with maize as it caused the maximum increase in the fresh biomass of maize. Of the bacterial isolates, the lowest increases in maize fresh biomass were observed in treatments S1L2 and S1L4, at 11% and 13%, respectively, produced by the inoculation of strain S1 (PML-63) as compared to the control. The greatest increase in the oven-dried biomass of maize was detected in response to inoculation with S4 (PML-79) and S1 (PML-63) bacterial strains, showing  
Figure 3: Remediation influences of bacterial isolates on root length (cm) (**a**) and shoot length (cm) (**b**) of maize cultivated in crude oil-contaminated soil. Values are means \(\pm\) standard deviation of three replicates. Means sharing the same case letters, for interaction and main effects for a parameter, do not differ significantly at \(p\leq 0.05\).