Research Article
Degradation of Asphaltenic Fraction by Locally Isolated Halotolerant Bacterial Strains
Table 3
Biochemical characteristics of the three most promising bacterial isolates.
| | Parameters | Asph1 | Asph2 | Asph3 |
| | Gram staining | + | − | + | | Spore former | + | − | − | | motility | + | + | − | | Growth aerobically | + | + | + | | Growth anaerobically | − | − | − | | Growth at 20°C | + | + | + | | Growth at 30°C | + | + | + | | Growth at 40°C | + | + | + | | Growth at 45°C | + | + | + | | Growth at 50°C | + | + | − | | Growth at 55°C | − | − | − | | NaCl 0% | + | + | + | | NaCl 5% | + | + | + | | NaCl 7.5% | + | + | + | | NaCl 10% | − | + | + | | NaCl 12.5% | − | − | Doubtful | | NaCl 15% | − | − | − |
| | Biochemical tests |
| | 3% KOH | − | + | − | | Catalase | + | + | + | | Oxidase | + | + | − | | Relation to oxygen | + | + | + | | Sodium malonate utilization | − | + | − | | Aesculin hydrolysis | + | Doubtful | − | | KCN resistance | + | + | Doubtful | | Nitrate reduction | + | CR | + | | Nitrite reduction | + | CR | − | | Methyl red (MR) test | − | − | − | | Voges-Proskauer (V.P.) test | − | − | − | | Oxidation-fermentation (O/F) test | +/+ | +/+ | −/+ | | Indole production | − | − | − | | Citrate utilization | + | Doubtful | − | | H2S production | − | − | − | | Levan formation | + | − | + |
| | Carbohydrate fermentation |
| | D (−) Glucose | (+ve) acid production | (+ve) acid production | (+ve) acid production | | D (+) Arabinose | − | (+ve) acid production | − | | Cellobiose | (+ve) acid production | − | − | | Dextrine | (+ve) acid production | − | − | | D (−) Fructose | (+ve) acid production | − | (+ve) acid production | | D (−) Galactose | − | (+ve) acid production | − | | D (−) Lactose | − | − | − | | Maltose | (+ve) acid production | − | (+ve) acid production | | D (−) Mannitol | − | − | (+ve) acid production | | D (+) Mannose | (+ve) acid production | (+ve) acid production | − | | D (−) Raibose | (+ve) acid production | (+ve) acid production | − | | Rhamnose | − | − | − | | Starch | (+ve) acid production | − | − | | Sorbitol | − | − | − | | D (+) Sucrose | (+ve) acid production | − | − | | D (+) Trehalose | (+ve) acid production | − | (+ve) acid production | | D (+) Xylose | − | (+ve) acid production | − | | D (+) Raffinose | − | − | − | | Inulin | − | − | − |
| | Extracellular enzyme production |
| | Amylase | + | − | Doubtful | | Gelatinase | + | + | − | | Lipase | + | − | − | | Pectinase | + | − | − | | Urease | + | + | + | | Cellulase | + | − | + | | Growth on blood | + | + | + | | Blood haemolysis | Beta haemolysis | Beta haemolysis | Gamma haemolysis |
| | Growth on agar medium |
| | King’s (A) agar | − | + | − | | King’s (B+) agar | − | + | − | | Mannitol salt agar (MSA) | + | − | + | | MacConkey agar (MA) | − | + | − |
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+ve: positive; −ve: negative; CR: complete reduction.
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