Impact of additives on syntrophic propionate and acetate enrichments under high-ammonia conditions

Sammanfattning

High ammonia concentrations in anaerobic degradation systems cause volatile fatty acid accumulation and reduced methane yield, which often derive from restricted activity of syntrophic acid-oxidising bacteria and hydrogenotrophic methanogens. Inclusion of additives that facilitate the electron transfer or increase cell proximity of syntrophic species by flocculation can be a suitable strategy to counteract these problems, but its actual impact on syntrophic interactions has yet to be determined. In this study, microbial cultivation and molecular and microscopic analysis were performed to evaluate the impact of conductive (graphene, iron oxide) and non-conductive (zeolite) additives on the degradation rate of acetate and propionate to methane by highly enriched ammonia-tolerant syntrophic cultures derived from a biogas process. All additives had a low impact on the lag phase but resulted in a higher rate of acetate (except graphene) and propionate degradation. The syntrophic bacteria 'Candidatus Syntrophopropionicum ammoniitolerans', Syntrophaceticus schinkii and a novel hydrogenotrophic methanogen were found in higher relative abundance and higher gene copy numbers in flocculating communities than in planktonic communities in the cultures, indicating benefits to syntrophs of living in close proximity to their cooperating partner. Microscopy and element analysis showed precipitation of phosphates and biofilm formation in all batches except on the graphene batches, possibly enhancing the rate of acetate and propionate degradation. Overall, the concordance of responses observed in both acetate- and propionate-fed cultures highlight the suitability of the addition of iron oxide or zeolites to enhance acid conversion to methane in high-ammonia biogas processes.

Nyckelord

Syntrophy; Zeolite; Graphene; Iron oxide; Biogas

Publicerad i

Applied Microbiology and Biotechnology
2024, volym: 108, nummer: 1, artikelnummer: 433
Utgivare: SPRINGER

SLU författare

• Pinela, Eduardo

  • Institutionen för molekylära vetenskaper, Sveriges lantbruksuniversitet
    

• Schnürer, Anna

  • Institutionen för molekylära vetenskaper, Sveriges lantbruksuniversitet
    

• Moestedt, Jan

  • Institutionen för molekylära vetenskaper, Sveriges lantbruksuniversitet
    
  • Linköpings universitet
  • Tekniska verken i Linköping AB

• Westerholm, Maria

  • Institutionen för molekylära vetenskaper, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Mikrobiologi

Publikationens identifierare

• DOI: https://doi.org/10.1007/s00253-024-13263-7

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/131654