Biomedical subjects
Publications and source records attributed to S Rothenburger.
We developed a new screening method for potential wood preservatives based on decolorization of the dye Remazol Brilliant Blue R by extracellular oxidative agents produced by wood decay fungi. Oxidative biodegradation of lignin yielded decolorized zones around and under fungal cultures on a dyed agar medium. Inhibitory effects were detected by direct observation and measurement of the decolorized zones.
Selective culturing of pseudomonads that could degrade quinoline led to enrichment cultures and pure cultures with expanded substrate utilization and transformation capabilities for substituted quinolines in immobilized and batch cultures. Immobilized cells of the pseudomonad cultures rapidly transformed quinolines to hydroxyquinolines in bioreactors and were able to tolerate higher substrate concentrations compared with batch cultures. After prolonged incubation on a mixture of quinoline and 6-methylquinoline, a quinoline-degrading culture of Pseudomonas putida developed the ability to biodegrade 6-methylquinoline, which initially was resistant to microbial attack, as a sole source of carbon and energy. 6-Methylquinoline was also degraded in a nonaqueous solution by this strain of P. putida when a solution of 6-methylquinoline in decane was flowed through an immobilized-cell fixed-bed bioreactor.
Several bacterial cultures were isolated that are able to degrade quinoline and to transform or to degrade methylquinolines. The degradation of quinoline by strains of Pseudomonas aeruginosa QP and P. putida QP produced hydroxyquinolines, a transient pink compound, and other undetermined products. The quinoline-degrading strains of P. aeruginosa QP and P. putida QP hydroxylated a limited number of methylquinolines but could not degrade them, nor could they transform 2-methylquinoline, isoquinoline, or pyridine. Another pseudomonad, Pseudomonas sp. strain MQP, was isolated that could degrade 2-methylquinoline. P. aeruginosa QP was able to degrade or to transform quinoline and a few methylquinolines in a complex heterocyclic nitrogen-containing fraction of a shale oil. All of the quinoline- and methylquinoline-degrading strains have multiple plasmids including a common 250-kilobase plasmid. The 225-, 250-, and 320-kilobase plasmids of the P. aeruginosa QP strain all contained genes involved in quinoline metabolism.
Isoquinoline-degrading microbial cultures were isolated from oil- and creosote-contaminated soils. The establishment of initial enrichment cultures required the use of emulsified isoquinoline. Once growth on isoquinoline was established, isoquinoline emulsification was no longer required for utilization of isoquinoline as the sole source of carbon and nitrogen by these cultures. An isoquinoline-degrading Acinetobacter strain was isolated from one of the enrichment cultures. The degradation of isoquinoline was accompanied by the accumulation of a red cell-associated pigment and of 1-hydroxyisoquinoline, which was further degraded to unknown intermediary ring-cleavage products and carbon dioxide.