BioChem - DOS

Investigation of intermittent air exposure on four-stage and one-stage anaerobic semi-continuous mixed-acid fermentations

Bioresource technology : biomass, bioenergy, biowastes, conversion technologies, biotransformations, production technologies

Golub, K.W.; Smith, A.D.; Hollister, E.B.; Gentry, T.J.; Holtzapple, M.T.

This study evaluated anaerobic mixed-acid countercurrent fermentations in both strict S (minimal oxygen) and relaxed R (high oxygen) conditions. In relaxed fermentations, filter solids and liquids were exposed to air for 90min every 56h. The total acid concentrations for four-stage trains were 23.0 (4S) and 22.1 (4R) g/L<SUB>Liq</SUB>, and for one-stage trains were 17.2 (1S) and 18.4 (1R) g/L<SUB>Liq</SUB>. The strict and relaxed trains had statistically similar exit yields. The strict trains had significantly more high-molecular-weight carboxylic acids. The relaxed trains had slightly higher conversion and slightly lower selectivity, but not significantly. Air exposure had no significant effect on the bacterial profiles of the strict and relaxed fermentations. For all fermentations, the most abundant bacterial genus was Prevotella, a strict anaerobe. This study shows that the mixed-culture community is oxygen tolerant because it maintains fermentation performance during oxygen-induced stress.

2011

Elsevier Applied Science

0960-8524

102

8

pp.5066-5075

10.1016/j.biortech.2011.02.011

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART55729723

Carboxylate platform; Aerotolerance; Mixed culture; Anaerobic countercurrent fermentation; MixAlco(TM) process