Recombinant Zymomonas mobilis ZM4(pZB5) has the
pZB5 plasmid transformed into the host strain and
was kindly made available by Dr Min Zhang (NREL,
Golden, CO). The Escherichia coli genes for production
of xylose isomerase, xylulokinase, transketolase,
and transaldolase have been introduced into the pZB5
plasmid. These confer xylose assimilation and fermentation
capability. The strain was maintained as frozen
stock culture in growth media (see below) supplemented
with 10 μg ml−1 tetracycline and 10% (v/v)
glycerol at – 70 ◦C.