Continuous aerobic conversion of poultry waste into single‐cell protein using a single reactor: Kinetic analysis and determination of optimal conditions

Abstract

AbstractA single‐stage aerobic continuous process for the conversion of poultry waste into single‐cell protein is described. The slurried manure was supplemented by molasses. Kinetics and possible mechanisms for the suggested conversion‐scheme have been investigated. A Box–Wilson experimental design has been employed to elucidate the effect of environmental conditions on reactor performance. Temperature, pH, and percent solids concentration in the feed (media composition) were the independent process variables, while the minimum residence time for the nearly complete utilization of total uric acid and ammonia nitrogen, the amount of carbon required per gram of nitrogen consumed, and protein content of the product were considered as dependent variables. Optimal environmental conditions for the minimum raw material cost and for the maximum percent protein, lysine, and methionine content of the product were determined. The operating conditions of 25°C, pH 7.5, 1.5% solids in the feed, and a residence time of 8.1 hr were found to be the most appropriate conditions maximizing the “profit” function, which is defined as the difference between the product value and raw material cost.