Isolation, evaluation and use of two strong, carbon source-inducible promoters from Corynebacterium glutamicum.
OBJECTIVE
To obtain strong, carbon source-inducible promoters useful for industrial applications of Corynebacterium glutamicum.


RESULTS
DNA microarray and qRT-PCR enabled identification of the promoters of cgR_2367 (malE1) and cgR_2459 (git1) as strong, maltose- and gluconate-inducible promoters, respectively, in C. glutamicum. Promoter probe assays revealed that in the presence of the inducing sugars, PmalE1 and Pgit1, respectively, facilitated 3.4- and 4.2-fold increased beta-galactosidase activities compared to the same activity induced by glucose. In addition, PmalE1 was not functional in Escherichia coli, in which Pgit1 function was repressible, which enabled the cloning of a hitherto 'difficult-to-clone' heterologous gene of a lignocellulolytic enzyme, whose secretion was consequently induced by the carbon sources.


CONCLUSIONS
PmalE1 and Pgit1 are strong, carbon source-inducible promoters of C. glutamicum whose characteristics in E. coli are integral to the secretion ability of C. glutamicum to secrete lignocellulolytic enzyme.


CONCLUSIONS
Corynebacterium glutamicum, like its counterpart industrial workhorses E. coli and Bacillus subtilis, does exhibit strong, carbon source-inducible promoters, and the functionality of two of which was demonstrated in this study. While this study may be most relevant in the ongoing efforts to establish technologies of the biorefinery, it should also be of interest to general microbiologists exploring the versatility of industrial micro-organisms. In so doing, the study should impact future advances in industrial microbiology.
Okibe
N
N
Research Institute of Innovative Technology for the Earth, Kizugawadai, Kizugawa, Kyoto, Japan.
Suzuki
N
N
Inui
M
M
Yukawa
H
H
D001412:Bacillus subtilis / Q000235:genetics; D002241:Carbohydrates / Q000494:pharmacology; D002244:Carbon; D048230:Corynebacterium glutamicum / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000502:physiology*; D007218:Industrial Microbiology; D011401:Promoter Regions, Genetic
D002241:Carbohydrates; D002244:Carbon