Journal
MOLECULAR BIOTECHNOLOGY
Volume 45, Issue 2, Pages 155-160Publisher
HUMANA PRESS INC
DOI: 10.1007/s12033-010-9254-9
Keywords
Heme-dependent catalase; Heterologous expression; Lactobacillus rhamnosus; Oxidative stress
Funding
- Ministry of Science and Technology of the People's Republic of China [2007AA 10Z354, 2006AA10Z317]
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Lactic acid bacteria (LAB) are generally sensitive to hydrogen peroxide (H2O2), Lactobacillus sakei YSI8 is one of the very few LAB strains able to degrade H2O2 through the action of a heme-dependent catalase. Lactobacillus rhamnosus strains are very important probiotic starter cultures in meat product fermentation, but they are deficient in catalase. In this study, the effect of heterologous expression of L. sakei catalase gene katA in L. rhamnosus on its oxidative stress resistance was tested. The recombinant L. rhamnosus AS 1.2466 was able to decompose H2O2 and the catalase activity reached 2.85 mu mol H2O2/min/10(8) c.f.u. Furthermore, the expression of the katA gene in L. rhamnosus conferred enhanced oxidative resistance on the host. The survival ratios after short-term H2O2 challenge were increased 600 and 10(4)-fold at exponential and stationary phase, respectively. Further, viable cells were 100-fold higher in long-term aerated cultures. Simulation experiment demonstrated that both growth and catalase activity of recombinant L. rhamnosus displayed high stability under environmental conditions similar to those encountered during sausage fermentation.
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