Highly Efficient Conversion of Lactate to Pyruvate Using Whole Cells of Acinetobacter sp.

摘要

On an industrial scale,the production of pyruvate at a high concentration from th cheaper lactate substrate is a valuable process.To produce pyruvate fromlactate by whole cells,various lactate-utilizing microorganisms were isolated from soil samples.Among them,strain WLIS,identified as Acinetobacter sp.,was screened as a pyruvate producer.For the pyruvate preparation from lactate,the preparative conditions were optimized with whole cells of the strain.The cells cultivated in the medium containing 100 mM of L-lactate showed the highest biotrasformation efficiency formlactate of pyruvate.The optimized dry-cell concentration,pH,and temperature of reaction were 6 g/L,pH 7.0-7.5,and 30 deg C,respectively.The influences of ethylenediaminetetraacetic acid (EDTA)and aeration on a biotransformation reaction were carried out under the test conditions.Underthe optimized reaction conditions,L-lactate at concentrations of 200 and 500 mM were almost totally stoichiometrically converted into pyruvate in 8 and 12 h,respectively.About 60% of 800 mM of L-lactate was transformed into pyruvate in 24 h,respectively.About 60% of 800 mM of L-lactate was trasformed into pyruvate in 24 h.This reduced conversion rate is probably due to the high substrate inhibition in biotransformation.