Microbial Community Analysis of the Anaerobic Digestion Process and the Early Stage of Composting of Pig Manure Using PCR-DGGE

This study was conducted to investigate microbial community changes during the field-scale composting of the anaerobic digested pig manure sludge. Samples were obtained from an influent tank (Inf.) and anaerobic digestion tank (A. d.) of pig manure slurry, and the early stage of compost depot (Com. 1 and Com. 2). Input of the compost process was produced by the solid-liquid separation process of the anaerobic digested pig manure. Ecoplate revealed that anaerobic digestion tank samples had high utilization of amino acid-based substrates and carboxylic acid-based substrates, and, similar to the influent tank, had the lowest utilization of carbohydrate-based substrates. Specific substrate utilizations increased as time passed during the composting process. Average well color development and the Shannon index were highest in the compost depot samples. Principal component analysis confirmed differences between the three composting process groups: influent tank, anaerobic digestion tank, and compost depot. Thirty-nine bands from the DGGE fingerprint were selected and identified, and showed that the majority of clones were uncultured bacteria that are observed during animal manure disposal or anaerobic digestion. Keywords— Anaerobic digested pig manure, Microbial community, Composting, CLPP, DGGE