Researches on photo-utilization of Zn-bacteriochlorophyll-containing phototrophic bacteria

• Project/Area Number: 13660073
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 応用微生物学・応用生物化学
• Research Institution: Iwate University
• Principal Investigator: WAKAO Norio Iwate University. Department of Agro-bioscience, Professor, 農学部, 教授 (30003784)
• Project Period (FY): 2001 – 2002
• Project Status: Completed (Fiscal Year 2002)
• Budget Amount: ¥3,500,000 (Direct Cost: ¥3,500,000); Fiscal Year 2002: ¥700,000 (Direct Cost: ¥700,000); Fiscal Year 2001: ¥2,800,000 (Direct Cost: ¥2,800,000)
• Keywords: Zn-bacteriochlorophyll / acidophilic aerobic phototrophic bacteria / Acidiphilium / current output / ATP production / reducing power production / CO_2 fixation

Research Abstract

It has been thought for a long time that Mg-(bacterio) chlorophylls are essential for the photosynthesis in nature. However, the new photosynthetic pigment, Zn-containing bacteriochlorophyll (Zn-BCh1) was discovered to be present in the acidophilic aerobic heterotrophic bacteria, Acidiphilium sp, and to be physiologically functional in cells. The present researches were made, using Acidiphilium rubrum as the type strain, on the conversion of light energy into electrical energy (current generation) via photosynthesis, the productions of chemical energy (ATP) and reducing power (NADPH), and CO_2 fixation under illumination.
The current outputs using electrochemical cells added with the mediator (HNQ) under illumination were investigated under various conditions. As a result photo-induced current outputs could be detected in fresh bacterial cells. The productions of ATP and NADPH were dependent on the light intensity. The ^<14>CO_2 analyses using both intact cells and cell membrane fractions revealed the fixation of CO_2 under aerobic and light conditions.