Genomic analysis of a xylose operon and characterization of novel xylose isomerase and xylulokinase from Bacillus coagulans NL01
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To investigate the xylose operon and properties of xylose isomerase and xylulokinase in Bacillus coagulans that can effectively ferment xylose to lactic acid.
The xylose operon is widely present in B. coagulans. It is composed of four putative ORFs. Novel xylA and xylB from B. coagulans NL01 were cloned and expressed in Escherichia coli. Sequence of xylose isomerase was more conserved than that of xylulokinase. Both the enzymes exhibited maximum activities at pH 7–8 but with a high temperature maximum of 80–85 °C, divalent metal ion was prerequisite for their activation. Xylose isomerase and xylulokinase were most effectively activated by Ni2+ and Co2+, respectively.
Genomic analysis of xylose operon has contributed to understanding xylose metabolism in B. coagulans and the novel xylose isomerase and xylulokinase might provide new alternatives for metabolic engineering of other strains to improve their fermentation performance on xylose.
KeywordsBacillus coagulans Lactic acid Xylose isomerase Xylose operon Xylulokinase
This study was supported by the Natural Science Foundation of Jiangsu Province of China (BK20130970), the National Natural Science Foundation of China (31300487, 51561145015), and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) for financial support.
Supplementary Table 1—Bacterial strains, plasmids and primers used in this study.
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