The 1.0 mM concentration was chosen
based on our previous study, which showed significant stimulation of -carotene production and little inhibition of cell growth in
recombinant yeast [31]. Consistent with our previous results [31],
the addition of H2O2 significantly increased -carotene production
and simultaneously induced the specific activities of SOD and
CAT. The specific activities of SOD and CAT after a 28 h cultivation
were 32.7% and 126.2% higher than those without H2O2 addition,
respectively. These results indicated that oxidative stress induced
by reactive oxygen species (ROS) can also stimulate the production
of -carotene in recombinant yeast and wild microorganisms
[10,35,36].