Conversion of organic acids to h(2) by Rhodospirillaceae grown with glutamate or dinitrogen as nitrogen source

Axenic cultures of Rhodopseudomonas capsulata. Rhodospirillum rubrum, and Rhodomicrobium vannielii grown with glutamate as the nitrogen source converted lactate, acetate, and butyrate to H(2) and CO(2). Conversion rates ranged from 100 to 926 mL H(2) L(r) (-1) day(-1) (where L(r) is the reactor contents), and efficiencies varied from 23 to 100% When grown with N(2), conversion rates up to 760 mL H(2) L(r) (-1) day(-1) and efficiencies up to 100%were achieved. Upon aging, cultures appear to rapidly increase in hydrogen uptake activity and furthermore decrease in nitrogenase activity, both factors leading to a slowdown of hydrogen production. This was particularly the case for diazotrophically grown photobacteria.