RRC ID 11454
Author Tashiro Y, Kaneko W, Sun Y, Shibata K, Inokuma K, Zendo T, Sonomoto K.
Title Continuous D-lactic acid production by a novel thermotolerant Lactobacillus delbrueckii subsp. lactis QU 41.
Journal Appl. Microbiol. Biotechnol.
Abstract We isolated and characterized a D-lactic acid-producing lactic acid bacterium (D-LAB), identified as Lactobacillus delbrueckii subsp. lactis QU 41. When compared to Lactobacillus coryniformis subsp. torquens JCM 1166 (T) and L. delbrueckii subsp. lactis JCM 1248 (T), which are also known as D-LAB, the QU 41 strain exhibited a high thermotolerance and produced D-lactic acid at temperatures of 50 °C and higher. In order to optimize the culture conditions of the QU 41 strain, we examined the effects of pH control, temperature, neutralizing reagent, and initial glucose concentration on D-lactic acid production in batch cultures. It was found that the optimal production of 20.1 g/l D-lactic acid was acquired with high optical purity (>99.9% of D-lactic acid) in a pH 6.0-controlled batch culture, by adding ammonium hydroxide as a neutralizing reagent, at 43 °C in MRS medium containing 20 g/l glucose. As a result of product inhibition and low cell density, continuous cultures were investigated using a microfiltration membrane module to recycle flow-through cells in order to improve D-lactic acid productivity. At a dilution rate of 0.87 h(-1), the high cell density continuous culture exhibited the highest D-lactic acid productivity of 18.0 g/l/h with a high yield (ca. 1.0 g/g consumed glucose) and a low residual glucose (<0.1 g/l) in comparison with systems published to date.
Volume 89(6)
Pages 1741-50
Published 2011-3
DOI 10.1007/s00253-010-3011-7
PMID 21165615
MeSH Culture Media / chemistry DNA, Bacterial / chemistry DNA, Bacterial / genetics DNA, Ribosomal / chemistry DNA, Ribosomal / genetics Glucose / metabolism Hot Temperature* Hydrogen-Ion Concentration Lactic Acid / metabolism* Lactobacillus delbrueckii / growth & development Lactobacillus delbrueckii / metabolism* Lactobacillus delbrueckii / radiation effects* Molecular Sequence Data RNA, Ribosomal, 16S / genetics Sequence Analysis, DNA
IF 3.34
Times Cited 42
General Microbes JCM 1166 JCM 1248