Paint Deterioration as a Result of the Growth of Aureobasidium pullulans on Wood.

Growth of Aureobasidium was noted on both painted and unpainted wood surfaces but not on painted glass slides, indicating that the source of carbon and energy for growth was not associated with paint components but was probably supplied by the wood. Several aromatic compounds related to aromatic extractives of wood were shown to support growth of this fungus.

Co-metabolism of fluorobenzoates by natural microbial populations.

Co-metabolic degradation of monofluorobenzoates was carried out by a mixed soil population in a basal salts medium. The monofluorobenzoates did not support growth of microorganisms but were shown to be subject to ring cleavage as a result of microbial activity. Rate of ring cleavage was increased by use of the co-substrate enrichment technique using glucose as the co-substrate. Results indicate that the monofluorobenzoates were subject to an initial co-metabolic attack with glucose, providing the energy necessary for co-metabolism to proceed to a point where complete metabolism became possible.

Enhancement of co-metabolism of chlorobenzoates by the co-substrate enrichment technique.

Chlorinated benzoates were degraded by bacteria contained in an activated sludge inoculum by a co-metabolic mechanism. This decomposition began after an initial lag period of 4 days and accounted for 63 to 69% degradation in 28 days. The co-substrate enrichment technique, using glucose as co-substrate, increased both the rate of microbial decomposition of the benzoates and the total amount of substituted aromatic compounds degraded.

Degradation of alkyl benzene sulfonate by Pseudomonas species.

Pseudomonas sp. HK-1 showed a direct relation between the concentration of alkyl benzene sulfonate (ABS) supplied and cell yields. Since growth on ABS alone did not occur, it was necessary to correlate the total energy obtained by the cells to the ABS concentration when glucose was supplied in a limiting concentration. Several types of metabolic attack in addition to the sulfonate removal were noted: (i) side-chain utilization as indicated by the production of tertiarybutyl alcohol and isopropanol and (ii) ring metabolism as indicated by the presence of phenol, catechol, mandelic acid, benzyl alcohol, and benzoic acid in spent growth media. Utilization of ABS was greatly enhanced by the presence of phenol. This enhancement suggests co-metabolism and that limited concentrations of phenolic products derived from ABS must be accumulated to get active metabolism of the ABS molecule.

Co-metabolism of methyl- and chloro-substituted catechols by an Achromobacter sp. possessing a new meta-cleaving oxygenase.

Co-metabolism of 3-methylcatechol, 4-chlorocatechol and 3,5-dichlorocatechol by an Achromobacter sp. was shown to result in the accumulation of 2-hydroxy-3-methylmuconic semialdehyde, 4-chloro-2-hydroxymuconic semialdehyde and 3,5-dichloro-2-hydroxymuconic semialdehyde respectively. Formation of these products indicated that cleavage of the aromatic nucleus of the substituted catechols was accomplished by a new meta-cleaving enzyme, catechol 1,6-oxygenase. This enzyme was equally active on both chloro- and methyl-substituted catechols.

Cometabolism of m-chlorobenzoate by an Arthrobacter.

Twenty isolates representing nine bacterial genera were obtained from enrichment cultures and were shown to cometabolize one or more of 22 substituted benzoates. One of the isolates, an Arthrobacter sp., cometabolized m-chlorobenzoate to a product identified as 4-chlorocatechol by thin-layer chromatography and ultraviolet and infrared spectroscopy. The data indicate that cometabolism by the arthrobacter results from the formation of products by its benzoate-oxiding enzyme system that are not acted upon by the catechol-metabolizing enzymes of the bacterium.