Isolation and Characterization of a Nonheterocystous Cyanobacterium, Lyngbya sp. Isolate No. 108, for Large-quantity Hydrogen Production

Abstract

Of 52 algal cultures isolated in the Seto Inland Sea area, one cyanobacterium produced large quantities of H₂. This organisms, isolate 108, was a freshwater, nonheterocystous, ensheathed and filamentous cyanobacterium, and was morphologically identified as a Lyngbya species. The optimum conditions for hydrogen production by it were: pH, 6.5; temperature, 3G°C; and light intensity, 1,000 lux, under fluorescent light. Low concentration of potassium nitrate (0.05 g/1) and yeast extract (0.01%) stimulated its growth and hydrogen production. Of the mineral salts tested, FeS0₄ markedly stimulated the growth of isolate 108. The highest rate of hydrogen production was 124ml/g cells/day. The carbohydrate content of cultures was decreased, by 85%, during hydrogen production.