13.2 Biodegradation in Biological Filter
Serratia marcescens, isolated from the activated sludge in a sewage treatment plant,
is capable of degrading ibuprofen. The degradation of ibuprofen required the
presence of primary substrate. After a 5-day culture with baking powder at 30
C
and pH 7, the highest degradation was achieved (93.47 Æ 2.37%). The bacterium
was applied to a small biological aerated filter device to form a biofilm with activated
sludge. The elimination of ibuprofen was 32.01–44.04% higher than for a biological
aerated filter without a bacterial component. The indigenous bacterial community
was able to effectively eliminate COD Mn (permanganate index) and ammoniacal
nitrogen in the presence of Serratia marcescens [58].
13.3 Bacterial Biodegradation
Raoultella sp., obtained after chemical mutagenesis of contaminated soil isolates,
effectively eliminated diclofenac (92% removal) over a period of 72 h at 28
C. The
degradation of the analgesic was investigated in detail by means of a cellular
catalyst. With this method, a maximum degradation of diclofenac of 91% was
achieved at pH 7 (1 g/L of diclofenac). The specific elimination rate at high
concentrations of diclofenac increased to 16.5 mg/h [59].
On the other hand, the bacterial strain Bacillus thuringiensis isolated from the soil
of the chemical factory “Organika-Azot” in Jaworzno, Poland, grown in
monosubstrates and co-metabolic systems with 1, 3, 5, 7, and 9 mg of ibuprofen
and 1 g of glucose as a source of carbon, eliminated ibuprofen up to 9 mg in 232 h in
the monosubstrate culture, while in the co-metabolic culture, the elimination of the
drug was six times faster [60].
In the co-metabolic system, the maximum specific growth rate of the bacterial
strain was 0.07 Æ 0.01 mg/mL/h and the substrate concentration K sμ
0.27 Æ 0.15 mg/L. The maximum specific ibuprofen elimination rate and the value
of the medium saturation constant were q max ¼ 0.24 Æ 0.02 mg/mL/h and the halfsaturation constant K s ¼ 2.12 Æ 0.56 mg/L, respectively [61].
B. thuringiensis can degrade ibuprofen in both monosubstrates and co-metabolic
systems. However, ibuprofen is not a sufficient carbon source for this strain. The
effective degradation of this drug occurs in the presence of glucose. Toxicity studies
showed that ibuprofen has a mean value of the microbial toxic concentration EC 50
of 809.3 mg/L and is higher than the toxic microbial concentration
545.50 Æ 7.78 mg/L [62].
This indicates that the strain examined is resistant to ibuprofen [61]. However, a
decrease in the optical density of bacterial cultures was also reported since these
compounds are not a sufficient carbon source. An additional carbon source can
improve the degradability of the strain by increasing biomass [63].
The above characteristics of B. thuringiensis suggest the possibility of its use as a
powerful and useful tool in the bioremediation of environments contaminated with
nonsteroidal anti-inflammatory drugs [61].
Biological Technologies Used for the Removal of Nonsteroidal Anti-inflammatory. . .
313
Serratia marcescens, isolated from the activated sludge in a sewage treatment plant,
is capable of degrading ibuprofen. The degradation of ibuprofen required the
presence of primary substrate. After a 5-day culture with baking powder at 30
C
and pH 7, the highest degradation was achieved (93.47 Æ 2.37%). The bacterium
was applied to a small biological aerated filter device to form a biofilm with activated
sludge. The elimination of ibuprofen was 32.01–44.04% higher than for a biological
aerated filter without a bacterial component. The indigenous bacterial community
was able to effectively eliminate COD Mn (permanganate index) and ammoniacal
nitrogen in the presence of Serratia marcescens [58].
13.3 Bacterial Biodegradation
Raoultella sp., obtained after chemical mutagenesis of contaminated soil isolates,
effectively eliminated diclofenac (92% removal) over a period of 72 h at 28
C. The
degradation of the analgesic was investigated in detail by means of a cellular
catalyst. With this method, a maximum degradation of diclofenac of 91% was
achieved at pH 7 (1 g/L of diclofenac). The specific elimination rate at high
concentrations of diclofenac increased to 16.5 mg/h [59].
On the other hand, the bacterial strain Bacillus thuringiensis isolated from the soil
of the chemical factory “Organika-Azot” in Jaworzno, Poland, grown in
monosubstrates and co-metabolic systems with 1, 3, 5, 7, and 9 mg of ibuprofen
and 1 g of glucose as a source of carbon, eliminated ibuprofen up to 9 mg in 232 h in
the monosubstrate culture, while in the co-metabolic culture, the elimination of the
drug was six times faster [60].
In the co-metabolic system, the maximum specific growth rate of the bacterial
strain was 0.07 Æ 0.01 mg/mL/h and the substrate concentration K sμ
0.27 Æ 0.15 mg/L. The maximum specific ibuprofen elimination rate and the value
of the medium saturation constant were q max ¼ 0.24 Æ 0.02 mg/mL/h and the halfsaturation constant K s ¼ 2.12 Æ 0.56 mg/L, respectively [61].
B. thuringiensis can degrade ibuprofen in both monosubstrates and co-metabolic
systems. However, ibuprofen is not a sufficient carbon source for this strain. The
effective degradation of this drug occurs in the presence of glucose. Toxicity studies
showed that ibuprofen has a mean value of the microbial toxic concentration EC 50
of 809.3 mg/L and is higher than the toxic microbial concentration
545.50 Æ 7.78 mg/L [62].
This indicates that the strain examined is resistant to ibuprofen [61]. However, a
decrease in the optical density of bacterial cultures was also reported since these
compounds are not a sufficient carbon source. An additional carbon source can
improve the degradability of the strain by increasing biomass [63].
The above characteristics of B. thuringiensis suggest the possibility of its use as a
powerful and useful tool in the bioremediation of environments contaminated with
nonsteroidal anti-inflammatory drugs [61].
Biological Technologies Used for the Removal of Nonsteroidal Anti-inflammatory. . .
313