Q-214. Phylogenetic Analysis of the Microbial Communities in a Novel Anaerobic Digester Treating Food Processing Wastes

M. Nelson1, A. Vent1, F. Schanbacher1, M. Morrison1,2, Z. Yu1;
1The Ohio State Univ., Columbus, OH, 2CSIRO Australia, St Lucia, AUSTRALIA.

The microbial diversity and community structures within anaerobic digestors (ADs) are complex and responsive to both the feedstock and the physicochemical conditions that occur during AD operation. Although numerous studies have been conducted to characterize the microbial communities in various ADs with the intent of optimizing their efficiency and stability, our functional knowledge of AD microbial communities still remains fragmented, especially in terms of monitoring AD operation. As part of a collaborative project to evaluate biogas production from a novel downflow-sand-bed-fillter AD, we have analyzed the microbial communities that developed when processing two distinct types of industrial food wastes: waste from a snack chip manufacturer and waste from a cheese manufacturer. The AD was initially inoculated with sludge from a UASB reactor used to process wastewater generated by a jam and jelly manufacturer. As revealed by DGGE profiling, the granular and planktonic biomass fractions of each AD sample had different bacterial but similar methanogen communities. The diversity of both bacteria and methanogens in each fraction of each AD was further analyzed using cloned rrs libraries. Approximately 2,000 unique clones were found using RFLP analysis and subsequently sequenced. Preliminary analysis of the rrs sequences showed that the different feedstocks led to the enrichment of distinct bacterial groups in the AD. Additional analysis of the rrs sequences also showed remarkable differences in microbial community structure between the two biomass fractions for all samples. These differences highlight the importance of individual microbial populations in the anaerobic digestion of characteristically different feedstocks.