Chiang Mai Journal of Science

     Hydrogen productions by photosynthetic bacteria (PSB) have been widely studied as it is a clean energy with high energy content potentials. PSB is a popular microorganism that utilizes solar energy to produce hydrogen which could lead to reduction in production costs. However, production that relies on solar energy has many limitations including; instability of weather, daylight limitation, and season changes. The main objective of this study was to produce hydrogen gas using Rhodopseudomonas palustris TN1 under 4 light systems. In this study, Glutamate-Acetate (GA) was used as the medium. Results show that the highest hydrogen production of 352.18±37.12 mL/L was achieved after 72 h of cultivation using a tungsten lamp as a light source. The solar indoor system, and the combination of solar indoor light used during daytime with tungsten lamp used at night produced the second and third highest volumes of hydrogen gas of 206.76±41.72 and 175.35±20.74 mL/L after 60 and 96 h of cultivation, respectively. However, there was no significant difference (p > 0.05) between these results. Based on hydrogen productivity, tungsten lamp system and the combination of solar indoor light and tungsten lamp resulted in the highest volumes of 9.04 and 8.40 mL/L/h, respectively. These results were accounted for 91-96% of the produced hydrogen. As per the electricity costs, tungsten lamp system and the combination of solar indoor light and tungsten lamp system required 0.30 and 0.36 baht/mL respectively. On the other hand, the solar indoor light system did not incur any electricity cost.