In this study, we isolated two indigenous hydrocarbon-degrading bacteria from tarball found in Rhu Sepuluh beach, Terengganu, Malaysia. These bacteria were identified based on their physiological characteristic and 16S rRNA gene sequence analysis, and they showed 99% similarity with Cellulosimicrobium cellulans DSM 43879 and Acinetobacter baumannii ATCC 19606 respectively. Their hydrocarbon-degrading capabilities were tested using diesel-oil as sole carbon source. Results analysed using GC-MS, showed diesel-oil alkanes were degraded an average 64.4% by C. cellulans and 58.1% by A. baumannii with medium optical density reaching 0.967 (C. cellulans) and 1.515 (A. baumannii) in minimal salt media at 32°C for 10days. Individual diesel-oil alkanes were degraded between 10%-95.4% by C. cellulans and 0.2%-95.9% by A. baumannii. Both strains utilized diesel-oil for growth. The study suggests both strains are part of indigenous hydrocarbon-degrading bacteria in tarball with potential for bioremediation of oil-polluted marine environment.
Phenol is mainly used by the industries to produce a variety of chemical products such as resins, textiles, pesticides, plastics and explosive. The wide use of phenol and other phenolic compounds by industries, has resulted in an increased presence of these toxic compounds in the environment as pollutants. Bio-removal of phenol by microorganisms especially bacteria has been demonstrated to be the most effective and economical approach compared to physio-chemical methods. The search for efficient phenol-degraders especially local sources to remediate local phenol pollution is important as indigenous bacteria usually have better survival and resilient to local geographical conditions. In this study, a phenol-degrading microorganism was isolated from local soil and waste water bodies. Identification was carried out using gram staining, 16s rRNA gene sequencing and molecular phylogeny analysis using the Phylip software. The isolates were inoculated in mineral salt media with 0.5 g/L phenol as the sole source of carbon. Phenol degradation was determined using 4-amino antipyrine method. Physical and cultural conditions influencing phenol degradation such as pH and temperature were optimized via one-factor-at-a-time. Through phylogeny analysis, the isolate was identified as Serratia sp. and the sequence was deposited the NCBI Genebank and accession number KT693287 was assigned to the bacteria. The highest degradation was achieved at pH 7.5 (phosphate buffer) and temperature of 30°C. Ammonium sulphate was established to be the best nitrogen source at the concentration of 0.4 g/L and a sodium chloride concentration of 0.15 g/L.
Aisami, A. | Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, Selangor, Malaysia
Biological treatment is understood to be the most efficient technique for phenol removal paralleled to other physio-chemical methods. 16s rRNA sequencing for the identification. Mineral salt media with 0.5 g/L phenol as the only carbon source. Temperature, pH, salinity and nitrogen source were optimised. The effects of heavy metals on the percentage of phenol degradation with were tested. Accession number of KT693288was assigned after identification. Temperature of 25-35°C,pH 7-8 phosphate buffer were the optimum and ammonium sulphate was established to be the paramount nitrogen source at 0.4 –0.5 g/L for isolate. The optimised conditions were found reducing the incubation period to 48 h with the ability to tolerate up to 0.2 g/L sodium chloride and degraded 50% and 1.1 g/L phenol. Meanwhile, the isolate AQ5-02 can also effectively degrade1000g/L phenol in the presence of heavy metals such as Cr, Zn, and Fe.
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