development of pdc-adh bifunctional enzyme fusion for ethanol production in bacillus subtilis

Bioethanol is one of the most important biofuels according to its combustion characteristics bacillus subtilis, gram-positive bacterium with potent enzyme secretion system and widespread application in production of industrial chemicals, seems to be a good candidate for bioethanol production a new approach was taken in this research to construct an ethanologenic b subtilis strain by heterologous expression of a recombinant fusion gene of zymomonas mobilis pyruvate decarboxylase (pdc) and saccharomyces cerevisiae alcohol dehydrogenase1 (adh1) in a strain of b subtlis wb600 in which the lactate dehydrogenase coding gene was genetically knocked-out the resulting strain was able to produce bioethanol in 2ytg medium supplemented with 6% waste potato flour during a 5-day incubation at 30°c, 120 rpm, maximum ethanol concentration of about 719 g/l was obtained after 48 h and a final concentration of 525 g/l could be measured at the end of the incubation period b subtilis wb600 δldh harboring empty phy300plk vector was used as control with no detectable ethanol production the results show that the pdc-adh1 fusion as a bifunctional enzyme can afford microbial ethanol production current study is the first report on ethanol production in b subtilis by development of pdc-adh bifunctional enzyme fusion