Microbial Communities Adapation to Anaerobic Digesters

LEONARDO ERIJMAN; LEANDRO GUERRERO; ESTEBAN ORELLANA; EVA FIGUEROLA; CAROL G DAVIES SALA

Buenos Aires

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

Sociedad Argentinas de Biociencias (SAIB, SAIC, SAI, SAA, SAB, SAB, SAFE, SAFIS, SAH, SAP)

Anaerobic digestion is a sustainable process widely used for organic waste management that stabilizes organic matter while geQHUDWLQJELRJDV3URGXFWLRQRIELRJDVGHSHQGVRQWKHDFWLYLWRID complex microbial community, in which methanogenic archaea and syntrophic bacteria are the leading actors. It has been argued that for certain substrates a suitable inoculum source may be critical for HIÀFLHQWELRJDVSURGXFWLRQ7KLVZRUNDLPVDWXQGHUVWDQGLQJWKH adaptation of inocula arising from different sources to food waste. Two lab-scale anaerobic reactors (5 L) were operated during 91 days and fed daily with increasing concentrations of food waste. Reactor operational parameters, such as biogas production, volatile IDWWDFLGVFRQFHQWUDWLRQ9)$YRODWLOHVROLGV96DQGWRWDODONDOLnity (TA) were measured on regular basis. Metagenomic DNA was REWDLQHGIURPVOXGJHVDPSOHVWDNHQZHHNO�LFURELDOFRPPXQLW analyses were conducted using two different set of primers for next JHQHUDWLRQVHTXHQFLQJ1*6DQDOVLVRQHWDUJHWLQJU51$69 V4 region of bacteria, another targeting mcrA gene that encodes methyl coenzyme-M reductase of methanogenic archaea. AbundanFHVZHUHHVWLPDWHGWKURXJKT3&5DVVDV Cumulative biogas production increased similarly in both reactors, during the acclimation phase, despite differences in the source of the inoculum. Non-Metrical Multidimentional Scaling (NMDS) analyses of the time series of acclimation showed that both bacteria and archaea samples clustered according to the reactor of origin. However, under our experimental set up adaptation to food waste led to convergence in bacterial composition, while methanogenic archaea displayed smaller changes and maintained a similar separation of the distances between samples of both reactors. These results suggest bacteria may play a critical role in the adaptation of the inoculum´s community to the substrate during start up stage to anaerobic digesters