Ts. Lee et al., OBSERVATIONS OF METABOLITE FORMATION AND VARIABLE YIELD IN THIODIGLYCOL BIODEGRADATION PROCESS - IMPACT ON REACTOR DESIGN, Applied biochemistry and biotechnology, 63-5, 1997, pp. 743-757
The complete microbial degradation of thiodiglycol (TDG), the primary
hydrolysis product of sulfur mustard, by Alcaligenes xylosoxydans ssp.
xylosoxydans (SH91) was accomplished in laboratory-scale stirred-tank
reactors. An Andrews substrate inhibition model was used to describe
the cell growth. The yield factor was not constant, but a relationship
with initial substrate concentration has been developed. Using a subs
trate-inhibition and variable-yield kinetic model, we can describe the
cell growth and substrate consumption in hatch and repeated batch fer
mentations. Several reactor-operating modes successfully degrade TDG c
oncentration to below 0.5 g/L. According to the experimental results,
the two-stage repeated batch operation has the best degradation effici
ency, and it also can degrade 500 mM TDG (approximate to 60 g/L) to 5
mM (approximate to 0.7 g/L) in <5 d. A hypothesis for explaining: vari
able-yield and byproduct formation based on the capacity and utilizati
on of metabolic loads is presented.