277BIO PRODUCTION OF HYDROGEN BY WATER – GAS SHIFT REACTION USING PACKED BED REACTORA packed bed reactor was used to examine production of hydrogen by water – gas shift reaction: CO + H2O H2 +CO2 using a photosynthetic bacterium (Rhodopseudomonas sp.). Carbon monoxide (CO) can be metabolized by this type of bacteria along with water to produce hydrogen (H2) and carbon dioxide. The performance of packed-bed was examined for conducting the above reaction to produce (H2) under aerobic conditions. The parameters studied were: liquid circulation rate, inlet CO gas flowrate and packing types. It was found that conversion of CO is increased with increasing liquid circulation rate while this conversion is decreased with increasing inlet CO gas flowrate.Three types of packing were used in this study. They were; 1- intalox saddles (6mm). 2- Ceramic rashig ring (1/4 in). 3-glass beads (6mm). It was found that intalox saddles provide higher conversion of CO than other packing types. Maximum Conversion of CO obtained in this research was 67%alaa_univ@yahoo.comResearch482013Packed bed,Hydrogen production,Water – gas shift reactionAlaa kareem Mohammed,Safaa Abdalrasool AliInstitute of Genetic Engineering and Biotechnology for Postgraduate Studies, University of Baghdad, Al jadiria, Baghdad, Iraq.,Institute of Genetic Engineering and Biotechnology for Postgraduate Studies, University of Baghdad, Al jadiria, Baghdad, Iraq.