Effects of Carbon Sources on Papulaspora thermophila at Various Temperatures

Thermophilic fungi, those with a maximum temperature for growth at or above 50 C and a minimum temperature for growth at or above 20 C (3), have been isolated from garden composts, manure of mammals, mushroom composts, stored peat, stacked oil kernels and most recently from snuff (4, 6, 10). Thermophiles are involved in the decomposition of plant materials and the buildup of humus (3). They are also involved in thermogenesis and spontaneous combustion which causes considerable financial loss (3, 6). In addition, some thermophiles are known to be pathogenic to animals, including man (3). A review of the literature, including Cochrane (2), Cooney and Emerson (3), and Crisan (4), indicated that few physiological studies have been reported concerning thermophilic fungi. Therefore, the data obtained from physiological studies dealing with thermophilic bacteria and thermophilic algae had to be applied to thermophilic fungi (4). Although valuable data had been reported concerning carbon nutrition for mesophilic fungi (2), there are few data pertaining to thermophilic fungi (2, 3, 4). Glucose, fructose, mannose, xylose, maltose, cellobiose, sucrose and starch are the carbohydrates which have been reported to support the best fungal growth (2, 5, 8). Increasing the carbohydrate concentrations, provided that adequate nitrogen is supplied, has resulted in an increase in growth (2). In addition, fungal growth is markedly affected by temperature (6). Of the limited number of studies that have been undertaken with thermophilic fungi, none has considered the effects of different temperatures on the utilization of various carbon sources. Although physiological studies of the recently discovered thermophilic fungus Papulaspora thermophila Fergus (7) have been reported by Chapman (1) and Prodromou and Chapman (9), they did not include the effects of various carbon sources on growth rate. Preliminary investigations (good growth on a synthetic agar medium) with P. thermophila indicated that it