Recovery of enriched anammox biofilm cultures after storage at cold and room temperatures for 164 days

Recovery of attached growth anammox-enriched cultures after storage for 9 or 164 days at cold (4 degrees C) and room (25-30 degrees C) temperatures was investigated in anaerobic sequencing batch reactors. The results clearly show that anammox-enriched cultures recovered more quickly after storage at room temperature than under cold temperature. Weekly acetate addition during anammox resuscitation after long-term storage did not change the performance of anammox attached-growth cultures, but was associated with lower abundance of both the hydrazineoxidoreductase (hzo) functional gene and the 16S rRNA gene of anammox bacteria relative to no acetate addition. The results from this work may be applicable in practice when anammox-enriched cultures need to be stored as inoculum before and/or after start up.