GLYCEROL CATABOLISM BY Lactobacillus rhamnosus ATCC 7469: EVIDENCE OF TWO GLYCEROL KINASE GENES

ALVAREZ, M. F.; MEDINA, R.; PASTERIS, S.E.; STRASSER DE SAAD, A.M.; SESMA, F.

JOURNAL OF MOLECULAR MICROBIOLOGY AND BIOTECHNOLOGY

Karger

Año: 2004 vol. 7 p. 170 - 181

1464-1801

Lactobacillus rhamnosus ATCC 7469 was able to grow in glycerol as the sole source of energy in aerobic conditions, producing lactate, acetate, and diacetyl. A biphasic growth was observed in the presence of glucose. In this condition, glycerol consumption began after glucose was exhausted from the culture medium. Glycerol kinase activity was detected in L. rhamnosus ATCC 7469, a characteristic of microorganisms which catabolize glycerol in aerobic conditions. Genetic analysis revealed that this strain possesses two glycerol kinase genes: gykA and glpK, that encode for two different glycerol kinases GykA and GlpK, respectively. The glpK gene is associated in an operon with ·glycerophosphate oxidase (glpO) and glycerol facilitator (glpF) genes. Transcriptional analysis revealed that only glpK is expressed when L. rhamnosus was grown on glycerol.