Efficient pyruvate production by a multi-vitamin auxotroph of Torulopsis glabrata: key role and optimization of vitamin levels

A multi-vitamin auxotroph, Torulopsis glabrata strain WSH-IP303, which can use ammonium chloride as a sole nitrogen source for pyruvate production, wa s selected. To optimize pyruvate yield and productivity, a simple but usefu l, orthogonal design method, was used to investigate the relationship betwe en thiamine, nicotinic acid, pyridoxine, biotin, and riboflavin. Thiamine w as confirmed to be the most important factor affecting pyruvate production. When the concentration of thiamine was 0.01 mg/l or 0.015 mg/l, glucose co nsumption was improved by increasing the nicotinic acid concentration. When the concentrations of nicotinic acid, thiamine, pyridoxine, biotin, and ri boflavin were 8.0, 0.015, 0.4, 0.04, and 0.1 mg/l, respectively, pyruvate c oncentration and yield reached 52 g/l and 0.52 g/g, respectively, in a 48-h flask culture. By employing a combination of the optimum vitamin concentra tions, a batch culture was conducted in a 2.5-1 fermenter with an initial g lucose concentration of 112 g/l; and the pyruvate concentration reached 69 g/l after 56 h (yielding 0.62 g/g).