Aromatic sulfonates (ASs) form one class of the major pollutants in wastewaters and natural waters and they are generally recalcitrant to biodegradation. Photodegradation and ozone treatment of ASs are effective for the removal, but tend to accumulate hydroxylated aromatic intermediates such as p-phenolsulfonate (PS) and hydroquinone sulfonate (HQS). To understand the possibility of the biodegradation of such compounds, one PS-assimilating bacterium and one HQS-assimilating bacterium were isolated from activated sludge and named PSY7 and HQS1, respectively. Strain PSY7 could degrade 1 mM PS in 30 h and grow on it, while strain HQS1 was also able to assimilate 1 mM HQS in 48 h. Genetic analysis and biochemical/physiological tests suggest that strains PSY7 and HQS1 belong to Cupriavidus basilensis and Delftia lacustris, respectively. As strain HQS1 could degrade both of PS and HQS, its biodegradation was further studied. Gene disruption study based on the genome sequence revealed that a gene (genA) necessary for the ring-cleavage of gentisate, which is very close to HQS in chemical structure, is involved in the HQS degradation. These information may contribute to the complete and efficient degradation of ASs.

 The phylogenetic analysis and 2－methylisoborneol production characteristics of the cyanobacterium Pseudanabaena isolated from drinking water sources in Japan were investigated. The seven strains were divided into four lineages in the 16S rRNA gene phylogenetic tree and three lineages in the 2－MIB synthase gene phylogenetic tree, and their positions in each phylogenetic tree were consistent. Culturing revealed that the strains tested grew within the temperature range of 10 to 20℃ and produced 2－methylisoborneol. Under nitrogen limination, P. limnetica WILD－11 had a higher 2－MIB content at 10℃ than at 20℃, and a significantly higher 2－MIB production ability at 10℃ than other strains. It is suggested that the ability to produce 2－MIB differs depending on the phylogeny of the 2－MIB synthase gene.