Search

Petroleum-hydrocarbon-degrading bacteria were obtained after enrichment on crude oil (as a 'chocolate mousse') in a continuous supply of Indonesian seawater amended with nitrogen, phosphorus and iron nutrients. They were related to Alcanivorax and Marinobacter strains, which are ubiquitous petroleum-hydrocarbon-degrading bacteria in marine environments, and to Qceanobacter kriegii (96.4-96.5% similarities in almost full-length 16S rRNA gene sequences). The Oceanobacter-related bacteria showed high n-alkane-degrading activity, comparable to that of Alcanivorax borkumensis strain SK2. On the other hand, Alcanivorax strains exhibited high activity for branched-alkane degradation and thus could be key bacteria for branched-alkane biodegradation in tropical seas. Oceanobacter-related bacteria became most dominant in microcosms that simulated a crude oil spill event with Indonesian seawater. The dominance was observed in microcosms that were unamended or amended with fertilizer, suggesting that the Oceanobacter-related strains could become dominant in the natural tropical marine environment after an accidental oil spill, and would continue to dominate in the environment after biostimulation. These results suggest that Oceanobacter-related bacteria could be major degraders of petroleum n-alkanes spilt in the tropical sea. DOI 10.1099/mic.0.030411-0

Research has been conducted on Comamonas testosteroni strain R5. Results indicate that this strain possesses an elaborate mechanism for mPH operon expression regulation which is more complicated than that discovered in other bacteria.

Results demonstrate that the PhcS protein represses the gratuitous expression of phenol-metabolizing enzymes in Comamonas testosteroni R5. Data indicate that in the presence of a substrate this repression is overcome by the bacterium.

Experiments involving phenol-fed activated sludge revealed that the outbreak of nonflocculating catabolic phenol-degrading bacteria populations caused the breakdown of the activated-sludge process. A competitive polymerase chain reaction analysis involving the use of gyrB sequences revealed that population structure in activated-sludge remained stable for 10 days after the introduction of phenol which was done a the rate of 0.4 g per liter per day.

The dominant population in phenol-digesting activated sludge was identified using temperature gradient gel electrophoresis of PCR-amplified 16S ribosomal DNA (rDNA) method, isolated and characterized. The research objective was to gain a better insight into phenol degradation in activated sludge. Results indicate that the phenotypes and genotypes of the dominant population in activated sludge were different from the genotypes and phenotypes of the representative phenol-degrading bacteria characterized in laboratories.

This study reports on a marine bacterium that accumulates fatty alcohols (C14,16,18) at more than 1% (w/w) of the dry cell weight. This unique bacterium, designated as strain 1–4, is related to the genus Reinekea. A novel gene cluster for fatty alcohol synthesis, phsAB, is identified from strain 1–4. The phsA product shows significant homology to fatty acyl‐CoA reductase (51% identity), whereas the phsB product shows very low homology to lipases. Interestingly, phsA alone causes Escherichia coli to accumulate fatty alcohols at 19% (w/w) of the dry cell weight. Moreover, the phsA‐containing E. coli accumulate more fatty alcohols (24%) and grow faster after phsB is introduced, indicating that phsAB could greatly assist the mass production of fatty alcohols. [ABSTRACT FROM AUTHOR]