Effects of storage on mixed-culture biological electrodes
Journal article, 2015
Storage methods are important to preserve the viability and biochemical characteristics of microbial
cultures between experiments or during periods when bioreactors are inactive. Most of the research on
storage has focused on isolates; however, there is an increasing interest in methods for mixed cultures,
which are of relevance in environmental biotechnology. The purpose of this study was to investigate the
effect of different storage methods on electrochemically active enrichment cultures. Acetate-oxidizing
bioanodes generating a current density of about 5 A m−2 were enriched in a microbial electrolysis cell.
The effect of five weeks of storage was evaluated using electrochemical techniques and microbial
community analysis. Storage by refrigeration resulted in quicker re-activation than freezing in 10%
glycerol, while the bioelectrochemical activity was entirely lost after storage using dehydration. The
results showed that the bioelectrochemical activity of bioanodes stored at low temperature could be
retained. However, during the re-activation period the bioanodes only recovered 75% of the current
density generated before storage and the bacterial communities were different in composition and
more diverse after storage than before.