Interactions of bacteria with different mechanisms for chitin degradation result in the formation of a mixed-species biofilm.

In this study, interactions between bacteria possessing either released or cell-associated enzymes for polymer degradation were investigated. For this, a co-culture of Aeromonas hydrophila strain AH-1N as an enzyme-releasing bacterium and of Flavobacterium sp. strain 4D9 as a bacterium with cell-associated enzymes was set up with chitin embedded into agarose beads to account for natural conditions, under which polymers are usually embedded in organic aggregates.

Quorum sensing by N-acylhomoserine lactones is not required for Aeromonas hydrophila during growth with organic particles in lake water microcosms.

It was investigated whether quorum sensing (QS) mediated by N-acylhomoserine lactones (AHLs) was important for heterotrophic bacteria from the littoral zone of the oligotrophic Lake Constance for growth with organic particles. More than 900 colonies from lake water microcosms with artificial organic aggregates consisting of autoclaved unicellular algae embedded in agarose beads were screened for AHL-production. AHL-producing bacteria of the genus Aeromonas enriched in the microcosms but AHLs could not be detected in any microcosm.

Isethionate as a product from taurine during nitrogen-limited growth of Klebsiella oxytoca TauN1.

Klebsiella oxytoca TauN1 represents a group of isolates which utilise taurine (2-aminoethanesulfonate) quantitatively as a sole source of combined nitrogen for aerobic growth. During growth, a compound is excreted, which has now been identified as isethionate (2-hydroxyethanesulfonate). An ion-chromatographic separation of isethionate was developed to quantify the putative isethionate, whose identity was confirmed by matrix-assisted, laser-desorption ionisation time-of-flight mass spectrometry.

Sulfoacetaldehyde is excreted quantitatively by Acinetobacter calcoaceticus SW1 during growth with taurine as sole source of nitrogen.

Eighteen enrichment cultures with taurine (2-aminoethanesulfonate) as the sole source of combined nitrogen under aerobic conditions were all successful, and 24 pure cultures were obtained. Only three of the cultures yielded an inorganic product, sulfate, from the sulfonate moiety of taurine, and the others were presumed to yield organosulfonates. Sulfoacetate, known from Rhodopseudomonas palustris CGA009 under these conditions, was not detected in any culture, but sulfoacetaldehyde (as a hydrazone derivative) was tentatively detected in the outgrown medium of nine isolates.