TY - JOUR
T1 - Role of mycelium and extracellular protein in the biodegradation of 2,4,6- trichlorophenol by Phanerochaete chrysosporium
AU - Armenante, P. M.
AU - Pal, N.
AU - Lewandowski, G.
PY - 1994
Y1 - 1994
N2 - The biodegradation of 2,4,6-trichlorophenol (2,4,6-TCP) by Phanerochaete chrysosporium was studied in batch systems. In experiments with mycelial suspension, the degradation of 2,4,6-TCP was found to occur in the absence of ligninase. Chloride ion was recovered in nearly stoichiometric amounts at the end of the process. The microorganism did not retain its degradation ability for more than 6 days under substrate-deficient conditions. Neither the mycelium nor the extracellular protein alone could degrade 2,4,6-TCP; both were required for complete degradation to occur. In experiments in which 2,4,6-TCP was exposed to the culture supernatant separated from its mycelium, negligible degradation was obtained and no chloride ion was recovered. No degradation was observed even when the supernatant was supplemented with hydrogen peroxide as a possible cosubstrate. In experiments performed with washed mycelium separated from its supernatant, no degradation took place until the mycelium released additional extracellular protein 5 to 6 h into the incubation. Additions of washed mycelium separated from its supernatant to active cultures also produced an increase in the rate of degradation in correspondence with the protein release. The protein release was independent of the presence of 2,4,6-TCP. The addition of cycloheximide to inhibit the synthesis of de novo proteins completely suppressed the release of protein by the mycelium and resulted in no 2,4,6-TCP degradation. Additions of culture supernatants containing a high concentration of extracellular protein to active cultures produced an increase in the rate of 2,4,6-TCP degradation. The results of this work indicate that the concentration of extracellular protein is the limiting factor in 2,4,6-TCP degradation but that no degradation can take place unless the mycelium is simultaneously present. This can be interpreted as an indication that sequential steps requiring both extracellular and cellular enzymes are involved in the degradation of 2,4,6- TCP by P. chrysosporium.
AB - The biodegradation of 2,4,6-trichlorophenol (2,4,6-TCP) by Phanerochaete chrysosporium was studied in batch systems. In experiments with mycelial suspension, the degradation of 2,4,6-TCP was found to occur in the absence of ligninase. Chloride ion was recovered in nearly stoichiometric amounts at the end of the process. The microorganism did not retain its degradation ability for more than 6 days under substrate-deficient conditions. Neither the mycelium nor the extracellular protein alone could degrade 2,4,6-TCP; both were required for complete degradation to occur. In experiments in which 2,4,6-TCP was exposed to the culture supernatant separated from its mycelium, negligible degradation was obtained and no chloride ion was recovered. No degradation was observed even when the supernatant was supplemented with hydrogen peroxide as a possible cosubstrate. In experiments performed with washed mycelium separated from its supernatant, no degradation took place until the mycelium released additional extracellular protein 5 to 6 h into the incubation. Additions of washed mycelium separated from its supernatant to active cultures also produced an increase in the rate of degradation in correspondence with the protein release. The protein release was independent of the presence of 2,4,6-TCP. The addition of cycloheximide to inhibit the synthesis of de novo proteins completely suppressed the release of protein by the mycelium and resulted in no 2,4,6-TCP degradation. Additions of culture supernatants containing a high concentration of extracellular protein to active cultures produced an increase in the rate of 2,4,6-TCP degradation. The results of this work indicate that the concentration of extracellular protein is the limiting factor in 2,4,6-TCP degradation but that no degradation can take place unless the mycelium is simultaneously present. This can be interpreted as an indication that sequential steps requiring both extracellular and cellular enzymes are involved in the degradation of 2,4,6- TCP by P. chrysosporium.
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U2 - 10.1128/aem.60.6.1711-1718.1994
DO - 10.1128/aem.60.6.1711-1718.1994
M3 - Article
C2 - 8031074
AN - SCOPUS:0028238721
SN - 0099-2240
VL - 60
SP - 1711
EP - 1718
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
IS - 6
ER -