Chemical composition of a sample of mycelium of Penicillium griseofulvum dierckx.

Both fungal and bacterial processes occur in the formation of soil organic matter (Waksman, 1938), which is itself composed, at least in part, of living micro-organisms and those parts of their remains which are resistant to chemical and enzymic decomposition. A knowledge of the composition of micro-organisms should, therefore, help to shed some light on the constitution of soil organic matter. Whilst much work has been done on the isolation and characterization of low molecular weight constituents offungi, there are no analyses of mycelium in which the various macromolecular compounds are well defined. A variety ofcarbohydrate preparations have been isolated from fungal tissue (Norman, Peterson & Houtz, 1932), and it has long been recognized that the cell wall of many fungal species is chitinous (Norman & Peterson, 1932; Brian, 1949). Protein concentrates have been extracted by Gorgica, Peterson & Steenback (1934) and Bohonos, Woolley & Peterson (1942). Takata (1929), and Akasi (1939) isolated nucleic acid preparations. Claims have been made for the isolation of 'crude lignin' or 'ligninlike complexes' by Thom & Phillips (1932), Phillips (1938) and Pinck & Allison (1944). Porges (1932) and Schulz (1937) studied the effect of cultural conditions on mycelial composition but, for the most part, their fractions are quite arbitrary and sometimes misleading. The literature is summarized and discussed by Foster (1949). In this paper various analytical methods have been studied from the point of view of their usefulness in the determination of the chemical components, particularly the macromolecular ones, of a sample of mycelium of Penicillium grieeofulvum Dierckx, grown as a surface pad. This is not a normal or important components of the soil flora, but was chosen for this work, which will be used as a model for future investigations on the predominant component of the soil, because it was readily available. No precautions were taken to separate spores, or to avoid autolysis, and values given are by no means claimed to be typical of mould mycelium.