Biochemistry of the Wood-rotting Fungi

In an examination ofthe volatile metabolic products of the odoriferous fungus Lentinuoa lepideu Fr., Birkinshaw & Findlay (1940) identified the methyl esters of p-methoxycinnamic, and cinnamic acids. Another acid, anisic acid, was also present as an ester but the nature of the alcohol moiety was left undetermined, although it was considered that the ester was probably the methyl ester. Another wood-rotting fungus which possesses a characteristic odour is Trametea uaveolenw (Linn.) Fr. This fungus is frequently responsible for decay in willow trees. The odour of the natural fruit body is recorded by Ramsbottom (1923) as 'strong of anise', that of the mycelium in culture is described by Badcock (1939) as 'strong, almost anisaldehyde'. The identification of the volatile products of this fungus forms the subject of the present communication. The fungus was grown on a liquid malt extract medium, and the volatile products in both the mycelium and the culture fluid were examined. The main product from both sources was methyl anisate (methyl p-methoxybenzoate). The odour of methyl anisate recalls that of T. suaveolens in culture, and this product is no doubt partly responsible for the smell produced by the fungus. The occurrence of anisic acid as its methyl -ester in the products of T. suaveolens strengthens the probability that it is also combined in this form in the products of Lentinue lepideus. In addition to methyl anisate small amounts of anisaldehyde (p-methoxybenzaldehyde) and of free anisic acid (p-methoxybenzoic acid) were detected. Anisaldehyde is a constituent of many ethereal oils derived from higher plants, particularly of those containing anethole, from which it is produced by atmospheric oxidation., It occurs in oil of anise which Trametes staveolene resembles in odour. The presence of small amounts of free anisic acid is to be expected. since anisaldehyde is readily oxidized to anisic acid when exposed to the air. The absence of appreciable amounts of cinnamic acid derivatives is of interest, since these were the major products isolated from Lentinus lepideus.