Mm. Laine et al., MICROBIAL FUNCTIONAL-ACTIVITY DURING COMPOSTING OF CHLOROPHENOL-CONTAMINATED SAWMILL SOIL, Journal of microbiological methods, 30(1), 1997, pp. 21-32
Microbial status during a successful full-scale bioremediation by comp
osting chlorophenol-contaminated soil was studied in three different w
ays: conventional enumeration of microbes on selective and general med
ia, microbial activity assessed by soil respiration, and community str
ucture studied by the utilization pattern of a large range of substrat
es using Biolog(R) microtitre plates. Utilization of ammonium, nitrate
and soluble P was also followed. Chlorophenols were well removed in a
ll compost piles which were mixtures of contaminated soil and bark chi
ps or straw compost. The best indicator of the actual chlorophenol deg
radation efficiency was the number of microbes growing on plates with
2 mM pentachlorophenol (PCP) as the sole carbon source. Nutrient analy
ses showed that ammonium was rapidly used, and nitrification took plac
e in some of the compost piles. The data from Biolog(R) microtitre pla
tes was analyzed using the toolbox of Matlab(R) mathematical software.
The areas under the substrate utilization curve were integrated for e
ach substrate used, and they were used for principal component analysi
s. We were able to see pile-specific substrate usage for piles contain
ing straw compost, but not for pile containing bark chips. All these c
haracteristic substrates were either amino acids or amines. The result
s suggested that fast-growing microbes responsible for utilization of
easily available substrates, measured by respiratory activity and subs
trate utilization patterns in Biolog, originated mainly from the added
bulking agents, straw compost and bark chips. The chlorophenol-degrad
ers originating from contaminated soil seemed not directly to contribu
te to the Biolog utilization pattern, but probably had benefited from
the enhanced general microbial activity in the composts by cometabolis
m or synergism. (C) 1997 Elsevier Science B.V.