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Hydrogen evolution as a consumption mode of reducing equivalents in green algal fermentation. [Chlamydomonas reinhardii; Chlorella pyrenoidosa; Chlorococcum minutum]

Journal Article · · Plant Physiol.; (United States)
OSTI ID:6063397

Dark anaerobic fermentation in the green algae Chlamydomonas MGA 161, Chlamydomonas reinhardtii, Chlorella pyrenoidosa, and Chlorococcum minutum was studied. Their isolate, Chlamydomonas MGA 161, was unusual in having high H/sub 2/ but almost no formate. The fermentation pattern in Chlamydomonas MGA 161 was altered by changes in the NaCl or NH/sub 4/Cl concentration. Glycerol formation increased at low (0.1%) and high (7%) NaCl concentrations starch degradation, and formation of ethanol, H/sub 2/, and CO/sub 2/ increased with the addition of NH/sub 4/Cl to above 5 millimolar in N-deficient cells. C. reinhardtii and C.pyrenoidosa exhibited a very similar anaerobic metabolism, forming formate, acetate and ethanol in a ratio of about 2:2:1. C. minimum was also unusual in forming acetate, glycerol, and CO/sub 2/ as its main products, with H/sub 2/, formate, and ethanol being formed in negligible amounts. In the presence of CO, ethanol formation increased twofold in Chlamydomonas MGA 161 and C. reinhardtii, but the fermentation pattern in C. minimum did not change. An experiment with hypophosphite addition showed that dark H/sub 2/ evolution of the Escherichia coli type could be ruled out in Chlamydomonas MGA 161 and C. reinhardtii. Among the green algae investigated, three fermentation types were identified by the distribution pattern of the end products, which reflected the consumption model of reducing equivalents in the cells.

Research Organization:
Osaka Univ., Japan
OSTI ID:
6063397
Journal Information:
Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 83:4; ISSN PLPHA
Country of Publication:
United States
Language:
English