The global proteomic response of the non-starter lactic acid bacteria Lactobacillus casei strain GCRL163 under carbohydrate depletion was investigated to understand aspects of its survival following cessation of fermentation. The proteome of L. casei GCRL163 was analysed quantitatively after growth in modified MRS (with and without Tween 80) with different levels of lactose (0% lactose, starvation; 0.2% lactose, growth limiting; 1% lactose, non-growth limited control) using gel-based and gel-free proteomic analysis. Results revealed carbohydrate starvation lead to suppression of lactose and galactose catabolic pathways as well as nucleotide and protein synthesis. Enzymes of the glycolysis/gluconeogenesis pathway, amino acid synthesis, pyruvate metabolism, and citrate metabolism became more abundant as well as other carbohydrate catabolic pathways suggesting increased optimisation of intermediary metabolism and scavenging. Tween 80 did not affect growth yield, however, proteins related to fatty acid biosynthesis were repressed in the presence of Tween 80. The data suggests that L. casei adeptly switches to a scavenging mode by adjusting energetic requirements when carbohydrate starved and thus can sustain survival for weeks to months. Explaining the adaptation of L. casei during lactose starvation will assist efforts to maintain viability of L. casei and extend its utility as a beneficial dietary adjunct.
History
Publication title
The Australian Society for Microbiology, Annual Scientific Meeting
Department/School
Tasmanian Institute of Agriculture (TIA)
Publisher
ASM
Place of publication
Adelaide, South Australia
Event title
The Australian Society for Microbiology, Annual Scientific Meeting