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PH08 Restoration of Contaminated Sites
(PH086A) Microbial Community Structure Changes During In-Vessel Composting-Bioremediation of PAH-Contaminated Solid Wastes.
ANTIZAR-LADISLAO, BLANCA1, LOPEZ-REAL, JOE1, GOLING, JENNIFER1, SPANOVA, KATARINA1, BENNETT, MARK1, BYHLIN, ERIKA2, RUSSEL, NICHOLAS1, BECK, ANGUS1, 1 IMPERIAL COLLEGE LONDON, WYE CAMPUS, WYE, UK2 UNIVERSITY OF UMEA, SWEDEN
ABSTRACT- Active compost has a high level of microbial activity, and a rapidly changing microbial community. Traditionally, the analysis of soil microbial communities has relied on culturing techniques using a variety of culture media designed to maximize the recovery of diverse microbial populations. However, only a small fraction (possibly<0.1%) of the soil microbial community is amenable to investigation using this approach. To overcome these problems, other methods such as phospholipid fatty acids (PLFA) analysis have been used in efforts to study a greater proportion of the soil microbial community. In this research, the dilution and spread plate method and PLFA analysis were comparatively investigated as a means of characterizing the relative changes in populations (e.g. mesophilic pseudomonads, thermophilic bacilli, actinomycetes and fungi) that may contribute to biodegradation of polycyclic aromatic hydrocarbons (PAHs) during in-vessel composting of PAH-contaminated soil. Composting studies were conducted in 200ml continuously aerated glass compost reactors during 100 days at three temperatures (380C, 550C and 700C), soil to amendment ratio 60:40 and moisture content 60%. Samples were analysed after 0, 7, 14, 21, 56, and 100days to investigate the effect of temperature on bacterial populations structure during composting of PAH contaminated waste. The results suggested that the process temperature had a significant effect on the microbial community structure during composting, proving significantly higher bacterial, actinomycetes and fungal populations at 370C than at 550C and 700C during the first 21days of composting. In addition, bacteria populations were significantly higher than actinomycetes and fungi, in this order, at 370C and 550C. Biomarkers isolated from the compost showed that the proportion of Gram-negative bacteria predominated following the thermophilic stage (after 21 days). Both methods were capable of detecting the predominating taxa and have proved useful for the analysis of microbial community successions during composting, but further research is needed on PLFA analysis so that it can routinely be used to characterize microbial community structures during composting.
Key words: composting, bioremediation, PLFA, PAHs
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