The aim of this work was to apply the evolutionary engineering to construct a mutant Saccharomyces
cerevisiae HJ7-14 resistant on 2-deoxy-D-glucose and with an enhanced ability of bioethanol production
from galactose, a mono-sugar in red algae. In batch and repeated-batch fermentations, HJ7-14 metabolized
5-fold more galactose and produced ethanol 2.1-fold faster than the parental D452-2 strain.
Transcriptional analysis of genes involved in the galactose metabolism revealed that moderate relief from
the glucose-mediated repression of the transcription of the GAL genes might enable HJ7-14 to metabolize
galactose rapidly. HJ7-14 produced 7.4 g/L ethanol from hydrolysates of the red alga Gelidium amansii
within 12 h, which was 1.5-times faster than that observed with D452-2. We demonstrate conclusively
that evolutionary engineering is a promising tool to manipulate the complex galactose metabolism in S.
cerevisiae to produce bioethanol from red alga.