Y. Li et al., Efficient pyruvate production by a multi-vitamin auxotroph of Torulopsis glabrata: key role and optimization of vitamin levels, APPL MICR B, 55(6), 2001, pp. 680-685
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).