Characterization of Acinetobacter SP. LWC1 isolated from contaminated water and its survivability under different stress condition

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dc.contributor.authorLim, Wui Chen
dc.date.accessioned2015-05-27T08:21:12Z
dc.date.available2015-05-27T08:21:12Z
dc.date.issued2014-09
dc.description.abstractThe role of PHA in the survival of bacteria in contaminated waters was investigated in this study. This study began with the isolation of a bacterium from water contaminated with domestic wastes, followed with the identification and characterization of the isolate and ended with the stress treatments to it. Based on the 16S rDNA, this isolate was closer to the Acinetobacter spp. Therefore, it was designated as Acinetobacter sp. LWC1. Besides this, the effect of various types of carbon sources such as sugars, oils and carboxylic acids and medium on PHA production was investigated in this study. Among all of the sugars, LB with 2% (w/v) of glucose yield the highest PHA content (11% DCW) with 0.4 g/L dry cell weight at 48 h. Meanwhile for the oils, LB with 3% (v/v) of used engine oil gave the highest PHA content (6.6% DCW) with 1.4 g/L dry cell weight at 72 h. The biosynthesis of P(3HB-co-3HV) copolymer was also evaluated in this study. However, it was recorded as second highest PHA content (9.14% DCW) with 0.98 g/L dry cell weight and 70 mol% 3HV at 96 h in LB medium by using 2% (w/v) of glucose supplemented with 0.25% (v/v) of valeric acid. For the MS medium, 2% (v/v) of used engine oil with 0.5% (v/v) of propionic acid gave the highest PHA content (3.99% DCW) with 0.30 g/L dry cell weight at 72 h. The relationships between PHAs accumulation in enhancing the survivability of Acinetobacter sp. LWC1 were carried out by comparing the bacteria with highest PHA and lowest PHA content under the same environmental stress conditions. It was found that Acinetobacter sp. LWC1 containing high PHA content of 11% DCW obtained from cultivation cultures in LB with 2% (w/v) glucose (LG) improved its endurance against environmental stresses such as high temperature, UV irradiation, ethanol treatment and osmotic pressure compared to the ones with low PHA content of 0.5% DCW obtained from cultivation cultures in LB with 2% (w/v) lactose (LA) and LB with 2% (v/v) palm oil (LPO) respectively.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/780
dc.subjectAcinetobacter SP. LWC1en_US
dc.titleCharacterization of Acinetobacter SP. LWC1 isolated from contaminated water and its survivability under different stress conditionen_US
dc.typeThesisen_US
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