초록
Co-culture of Clostridium butyricum and Rhodobacter sphaeroides displayed different types of H<SUB>2</SUB> photoproduction from starch: quick low-yield (2.6 mol/mol glucose), prolonged high-yield (6.1 mol/mol glucose) and delayed low-yield (4.2 mol/mol glucose). It depended primarily on the ratio of two species and, besides, some other factors. The first type H<SUB>2</SUB> photoproduction was similar to that in Clostridium, observed at high clostridia/purple bacteria ratio and promoted by low light intensity, temperature above and below optimum, reduced conditions, low initial pH or buffer concentration, high concentration of yeast extract (320 mg/L). The second type, high yield H<SUB>2</SUB> production, was favored by low clostridia/purple bacteria ratio, high light intensity, and high concentration of yeast extract (320 mg/L). The third type, delayed H<SUB>2</SUB> photoproduction, was observed at the lowest clostridia/purple bacteria ratio and was promoted by low concentration of yeast extract (25 mg/L). Thus, a well-known crucial effect of a species ratio on H<SUB>2</SUB> photoproduction was in turn controlled by other factors, especially yeast extract concentration.