MICROBIAL COMMUNITY STRUCTURE DYNAMICS DURING AERATED AND MIXED COMPOSTING

The impacts of management actions that can be taken during composting on product quality are often unclear.In this study the effects of mixing and aeration on the microbial community structure during composting were investigatedusing mixed and staticbed reactors operated at different aeration rates. Aeration had an impact on process temperature anddynamics in microbial community structure as measured by phospholipid fatty acid (PLFA) analysis. Mixing had a largerinfluence on microbial community structure dynamics when the process was aerated at 210 mL/min/kg than at 620 mL/min/kg.PLFA biomarkers that indicate microbial stress and anaerobic communities increased with time in all composting treatments.The increase was greater in treatments aerated at 620 mL/min/kg than at 210 mL/min/kg. During the later stages ofcomposting, PLFA biomarkers that indicate eukaryotic biomass increased in treatments aerated at 620 mL/min/kg butdecreased in treatments aerated at 210 mL/min/kg. This study demonstrated the extent by which compost microbial communitystructure can be influenced by mixing and aeration and that PLFA analysis can be used as a tool to better understand themicrobial community structure changes resulting from differences in management.