Journal
JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY
Volume 39, Issue 11, Pages 1685-1692Publisher
OXFORD UNIV PRESS
DOI: 10.1007/s10295-012-1176-z
Keywords
Glucokinase; Sporolactobacillus inulinus; Glucose metabolism; D-lactic acid production; Broad substrate specificity
Categories
Funding
- National Basic Research Program of China [2011CB707400]
- National High Technology Research and Development Program of China [2011AA02A202]
- PCSIRT
- PAPD
- [CXZZ11_0358]
Ask authors/readers for more resources
Sporolactobacillus inulinus, a homofermentative lactic acid bacterium, is a species capable of efficient industrial d-lactic acid production from glucose. Glucose phosphorylation is the key step of glucose metabolism, and fine-tuned expression of which can improve d-lactic acid production. During growth on high-concentration glucose, a fast induction of high glucokinase (GLK) activity was observed, and paralleled the patterns of glucose consumption and d-lactic acid accumulation, while phosphoenolpyruvate phosphotransferase system (PTS) activity was completely repressed. The transmembrane proton gradient of 1.3-1.5 units was expected to generate a large proton motive force to the uptake of glucose. This suggests that the GLK pathway is the major route for glucose utilization, with the uptake of glucose through PTS-independent transport systems and phosphorylation of glucose by GLK in S. inulinus d-lactic acid production. The gene encoding GLK was cloned from S. inulinus and expressed in Escherichia coli. The amino acid sequence revealed significant similarity to GLK sequences from Bacillaceae. The recombinant GLK was purified and shown to be a homodimer with a subunit molecular mass of 34.5 kDa. Strikingly, it demonstrated an unusual broad substrate specificity, catalyzing phosphorylation of 2-deoxyglucose, mannitol, maltose, galactose and glucosamine, in addition to glucose. This report documented the key step concerning glucose phosphorylation of S. inulinus, which will help to understand the regulation of glucose metabolism and d-lactic acid production.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available