Kinetics of growth and chemical composition ofFusarium moniliforme cultivated on carob aqueous extract for microbial protein production

Abstract

The kinetics of growth and the chemical composition ofFusarium moniliforme cultivated on aqueous carob pod extract were investigated. The extract was adjusted to provide 0.5, 1.0, 2.0 and 4.0% carob sugars supplemented with inorganic salts at the ratio: carob sugar: NH4H2PO4: MgSO4.7H2O=1:0.6:0.012. The extract contained 16 mg tannic acid (Folin-Dennis) per g of carob sugar. The phase of vigorous growth was exponential. Tannins were not observed to depress growth. The maximum value of 0.22 h−1 for a specific growth rate corresponding to a generation time of 3.15 h was obtained when the fungus was cultivated on a 4% carob sugar medium. The dry mycelium produced per g of consumed carob sugar was then 0.515 g. The protein and purine content was affected by the composition of the growth medium. Protein values up to 37.7% true (Lowry) and 53.1% crude (NX6.25) of dry mycelium were recorded. Mean purine contents were 89 and 116 μmol/g, corresponding to nucleic acid levels of 5.7 and 7.5% for mycelium grown on 0.5 and 4.0% carob sugar respectively. These findings linked with those previously reported regarding the good appearance and nutritional quality ofF. moniliforme (Drouliscos et al., 1976) make this fungus worthy of consideration for the production of protein.