Continuous fermentation to produce fungal protein. Effect of growth rate on the biomass yield and chemical composition of Fusarium moniliforme

Abstract

AbstractFusarium moniliforme was grown on a carob aqueous extract in a chemostat for fungal protein production. The substrate was adjusted to provide 0.5% carob sugars supplemented with inorganic salts. The dilution rate varied from 0.086 to 0.227 hr−1 under constant conditions of temperature (30°C), pH (4.5), and oxygen saturation (60–80%). A yield of 0.709 g dry mycelium/g consumed carob sugar and a productivity value of 0.687 g dry mycelium/liter hr−1 were obtained at μ = 0.205 hr−1. The maintenance coefficient was 0.077 g carob sugar/g dry mycelium hr−1. While the carbohydrate and purine content of dry mycelium increased at μ values from 0.114 to 0.205 hr−1 both true (Lowry) and crude (N × 6.25) protein contents decreased at the same μ range. Maximum values of 36.3% true and 47.9% crude protein of dry mycelium were obtained at μ = 0.114 hr−1, whereas a minimum purine content of 99.8 μmol/g corresponding to 6.42% nucleic acids was recorded at μ = 0.086 hr−1. It was concluded that a continuous fermentation of carob aqueous extract using F. moniliforme should be operated at growth rates of approximately 0.205 hr−1 in order to maximize protein production.