Moira E. K. Henderson

Utilization by Soil Fungi of p -Hydroxybenzaldehyde, Ferulic Acid, Syringaldehyde and Vanillin

SUMMARY: A number of fungi isolated from soils under a variety of vegetational types was found to attack p-hydroxybenzaldehyde, ferulic acid, syringaldehyde and vanillin. These compounds were used as sole source of carbon by the organisms tested. By means of spectrochemical methods and paper chromatography it was shown that vanillin and ferulic acid were converted to vanillic acid before the breaking of the benzene ring, and syringaldehyde was converted to syringic acid. The bearing of these results on the breakdown of lignin in soil is discussed.

The metabolism of aromatic compounds related to lignin by some hyphomycetes and yeast-like fungi of soil.

SUMMARY The metabolism of various lignin-related aromatic compounds by several soil Hyphomycetes and yeast-like fungi was investigated. Adaptation studies with whole organisms and cell-free extracts confirmed previously proposed metabolic pathways (Henderson & Farmer, 1955; Henderson, 1960). It was shown that protocatechuic acid is an intermediate in the metabolism of vanillin and ferulic acid. Protocatechuic acid oxidase activity of cell-free extracts of Pullularia pullulans was found to be stimulated by ferrous ions and to depend on -SH groups.

Metabolism of Methoxylated Aromatic Compounds by Soil Fungi

SUMMARY: The metabolism of methoxylated aromatic compounds by the soil fungi Haplographium sp., Hormodendrum sp. and Penicillium sp. has been investigated. A study of rates of decomposition of mono-methoxybenzoic acids by Hormo-dendrum sp. revealed that they are most rapidly attacked in the order para (p). meta (m) and ortho (o). In respiration studies with all three fungi the p form was again found to be metabolized most rapidly. In the initial stage of attack the methoxyl group is replaced by a hydroxyl group. Penicillium sp. also formed p-methoxyphenol from p-methoxyhenzoic acid. A study of the rates of metabolism of monohydroxy-benzoic acids revealed that they are attacked in the same order as the monometh-oxybenzoic acids. p-Hydroxybenzoc acid formed from p-methoxybenzoic acid is further metabolized to protoetechuic acid by Hormodendrum sp. and Pencillium sp. When veratric acid (3:4-dimethoxybenzoic acid) is incubated with Hormodendrum sp. and Penicillium sp. the methoxyl group in the p position is replaced by a hydroxyl group to give vanille acid. All three fungi formed two unidentified phenolic compounds from 2:4-dimethoxybenzoic acid. The possible significance of the results in the decomposition of lignin in soil is discussed.

Metabolism of lignin model compounds by Polystictus versicolor

Mats of Polystictus versicolor metabolized the lignin model compounds α-guaiacylglycol-β-guaiacyl ether (III) and α-guaiacylglycerol-β-guaiacyl ether (IV) but not the compounds α-veratrylglycol-β-guaiacyl ether (I) and α-veratrylglyerol-β-guaiacyl ether (II). Veratryl alcohol was formed from III. Veratraldehyde and veratryl alcohol were also formed solutions of p-hydroxybenzoic acid, protocatechuic acid, vanillin and vanillyl alcohol were metabolized by the fungus. Smaller amounts of veratraldehyde were liberated by the growing fungus and by preformed mats. None of the model compounds I to IV was oxidized by the aromatic-alcohol oxidase of P.versicolor.

Isolation, identification and growth of some soil hyphomycetes and yeast-like fungi which utilize aromatic compounds related to lignin.

SUMMARY Fungi were isolated from soil under several vegetational types by an enrichment technique with vanillin or p-hydroxybenzaldehyde as sole source of carbon. Although similar morphologically, the isolates obtained are classified in two separate groups, yeasts and hyphomycetes. A study was made of the growth in pure culture of representative species, namely, Pullularia pullulans, Margarinomyces heteromorpha and M. mutabilis on several aromatic compounds related to lignin.

The influence of trace elements on the metabolism of aromatic compounds by soil fungi.

SUMMARY: The effect of copper, iron, manganese and zinc on the metabolism of catechol, o-,m- and p-hydroxybenzoic, o-, m- and p-methoxybenzoic, 3:4-dimethoxybenzoic and vanillic acids was investigated. Aspergillus niger, Hormodendrum sp. and Penicillium sp. mycelia which were deficient in the various trace elements were the organisms used. Only iron had any marked effect on the rates of metabolism and on the accumulation of intermediate products of metabolism in the substrate solutions. The intermediate products identified were: protocatechuic acid from m-and p-hydroxybenzoic and p-methoxybenzoic acids; catechol from o-hydroxy-benzoic acid; vanillic acid from 3:4-dimethoxybenzoic acid; o-, m- and p-hydroxybenzoic acids from the corresponding mono-methoxybenzoic acids.

Enrichment in soil of fungi which utilize aromatic compounds

SummaryPellets containing various aromatic compounds were buried in soil in pots. Enrichment of fungi occurred on the pellets and in the soil surrounding them. A number of the fungi were isolated and some were of genera which had not been obtained by techniques used previously. Growth of the isolates on the aromatic compounds was studied.