Isolation And Identification Of Crude Oil Degrading Bacteria From Soil Polluted With Automobile Lubricants

RESULTS

Six distinct colonies were isolated from the Bushnell Haas agar and subjected to several biochemical tests. Two isolates were found to be the best crude oil degraders by measuring their optical densities at 600nm wavelength using spectrophotometer. The two best isolates were identified, and they were subjected to belong to the genera Micrococcus and Streptomyces.

Table 1 shows the morphological characteristics of the isolates.

Table 2 shows the microscopy results of the isolates.

Table 3 shows the morphological and biochemical test results of the selected isolates.

Table 4 shows the optical densities of the isolates.

The graphs if the optical densities of the isolates are also represented in figs 3.1 and 3.2.

3.1. COLONY MORPHOLOGY OF THE ISOLATES

Table 1: Morphology of the isolates on the Bushnell Haas

ISOLATES     COLOUR      ELEVATION     EDGE     TEXTURE      FORM       DENSITY

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IS1                      Milky               Raised               Entire        Smooth           Irregular      Opaque

IS2                      Milky                Flat                    Entire        Smooth           Irregular      Opaque

IS3                      Milky                Raised               Entire         Rough            Pinpoint        Opaque

IS4                      Milky                 Flat                   Serrated      Smooth          Irregular       Opaque

IS5                      Milky                Raised              Entire           Rough           Irregular        Opaque    

IS6                      Milky                 Flat                  Serrated       Smooth         Irregular         Opaque

3.2. MICROSCOPY OF ISOLATES

Table 2: MICROSCOPY OF ISOLATES

ISOLATES               GRAM REACTION                SHAPE                 ARRANGEMENT

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IS1                                Positive                                    Cocci                       Clusters

IS2                                Positive                                    Cocci                       Pairs

IS3                                Positive                                    Cocci                       Clusters

IS4                                Negative                                  Rod                          Pairs

IS5                               Positive                                    Cocci                        Clusters

IS6                               Positive                                    Rod                           Chains

3.3. BIOCHEMICAL TESTS RESULT OF SELECTED ISOLATES

Table 3: MORPHOLOGICAL AND BIOCHEMICAL TESTS RESULT OF SELECTED ISOLATES

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                                                         IS1                                         IS2

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Colour of colonies                       Milky                                     Milky

Shape                                           Cocci                                       Cocci

Gram reaction                                +                                             +

Catalase                                           +                                             +

Motility                                            +                                             _

Indole                                               +                                             +

Voges prokrauer                             +                                             +

Nitrate                                              _                                             _                                                     

Starch hydrolysis                            _                                              _

Methyl red                                       _                                              _

Simmon Citrate                               _                                              +

Maltose Fermentation                     A/G                                        A

Dextrose Fermentation                     _                                            A

Mannitol Fermentation                     A                                           A

Sucrose Fermentation                       _                                             _

Lactose Fermentation                        A                                            A

Implicated organism                    Micrococcus Spp            Streptomyces Spp

+       =     Positive reaction to the test                    A/G      =    Acid and gas production

_        =      Negative reaction to the test                   A         =    Acid production  

3,4, OPTICAL DENSITIES OF THE SELECTED ISOLATES

Table 4: OPTICAL DENSITY OF THE SELECTED ISOLATES

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                              0h            24h          48h          72h          96          120h          144h          168h

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IS1                      0,280        0.4720      0.944        1.104        1.104     1.191         1.231         0,908

IS2                     0.028         0.065        0.095        0.127        0.161      1.105        1.308          0.964

3.5. GRAPH OF OPTICAL DENSITIRS OF ISOLATES

Figure 3.1: Time-course of medium optical density changes during growth of IS1 isolates (Micrococcus Spp) on mineral salt medium with 0.5% concentration of lubricating oil (Crude oil product).

Figure 3.2: Time-course of medium optical density change during growth of IS2 isolate (Streptomyces Spp) on mineral salt medium with 0.5% concentration of lubricating oil (Crude oil product).