4.4 Biodegradation of Pollutants by WRF
The WRF Ganoderma lucidum was more effective in removing herbicide bentazon
than herbicide diuron as evident from leftover residues in the medium (Coelho et al.
2010). G. lucidum was more effective in degrading lindane in liquid fermentation
than in SSF (Kaur et al. 2016). In liquid medium, about 80% of initially added
lindane (4 ppm) was degraded at the end of 28-day incubation as against 38%
degradation in SSF. Inoculation of pesticide-fortified soils with the WRF
T. versicolor and P. chrysosporium increased bioremediation of insecticides (simazine, trifluralin, and dieldrin) in soil microcosms (Fragoeiro and Magan 2008). At
14 days incubation period in straw cultures of P. chrysosporium was able to
bioremediate 91% of the herbicide-isoproturon (Castillo et al. 2001). C. versicolor,
H. fasciculare, and S. hirsutum caused the highest remediation of terbuthylazine,
atrazine, and diuron (86%) in liquid culture, but poorly degraded metalaxyl to less
than 44% (Bending et al. 2002). They also demonstrated the deterioration of
pollutants when WRF grew on-farm “biobed” organic matrix and showed some
differences to that of submerged cultures. After 42 days, in biobed matrix
H. fasciculare and C. versicolor were able to bioremediate about a third of the
poorly available compound chlorpyrifos, among the tested WRF, S. hirsutum, shown
to be the most effective oxidizer of the pesticides. PCP biodegradation in contaminated field soils (100 to 2137 mg kg
À1 PCP) by T. versicolor (3 to 175 g kg
À1
inoculum) was evaluated by Ford et al. (2007). Furthermore, Schmidt et al. (2005)
observed a clear link with the amount of T. Versicolor fungal inoculums used and
colonization of fungal cultures in soil bioaugmented for bioremediation.
Soil contaminated with PCP biodegradation by immobilized WRF
Anthracophyllum discolor and P. chrysosporium on wheat straw was studied by
Rubilar et al. (2011). In the presence of a contaminant, high-level MnP activities and
fungal biomass was recognized in their studies. Moreover, 75% of pollutant degradation was consequently identified in immobilized fungal cultures on wheat grains in
the soil samples (Rubilar et al. 2011). Efficient bioremediation of atrazine by
immobilized A. discolor on formulating pelletized support was evaluated by Elgueta
et al. (2016). The list of recent studies on the bioremediation of xenobiotics by white
rot fungi is given in Table 4.4.
4.4.1 LE Involved in Bioremediation of Xenobiotic
Compounds
WRF is the most efficient organisms to secrete LMEs (LAC, MnP, LiP) for the
mineralization of lignin polymer. Oxidative and non-specific nature of these
enzymes shows the potential application in the bioremediation of environmentally
toxic pollutants. Among these ligninolytic enzymes laccase enzyme plays a major
role in the oxidation of various xenobiotic compounds and also there are several
4 Influence of Xenobiotics on Fungal Ligninolytic Enzymes
109
The WRF Ganoderma lucidum was more effective in removing herbicide bentazon
than herbicide diuron as evident from leftover residues in the medium (Coelho et al.
2010). G. lucidum was more effective in degrading lindane in liquid fermentation
than in SSF (Kaur et al. 2016). In liquid medium, about 80% of initially added
lindane (4 ppm) was degraded at the end of 28-day incubation as against 38%
degradation in SSF. Inoculation of pesticide-fortified soils with the WRF
T. versicolor and P. chrysosporium increased bioremediation of insecticides (simazine, trifluralin, and dieldrin) in soil microcosms (Fragoeiro and Magan 2008). At
14 days incubation period in straw cultures of P. chrysosporium was able to
bioremediate 91% of the herbicide-isoproturon (Castillo et al. 2001). C. versicolor,
H. fasciculare, and S. hirsutum caused the highest remediation of terbuthylazine,
atrazine, and diuron (86%) in liquid culture, but poorly degraded metalaxyl to less
than 44% (Bending et al. 2002). They also demonstrated the deterioration of
pollutants when WRF grew on-farm “biobed” organic matrix and showed some
differences to that of submerged cultures. After 42 days, in biobed matrix
H. fasciculare and C. versicolor were able to bioremediate about a third of the
poorly available compound chlorpyrifos, among the tested WRF, S. hirsutum, shown
to be the most effective oxidizer of the pesticides. PCP biodegradation in contaminated field soils (100 to 2137 mg kg
À1 PCP) by T. versicolor (3 to 175 g kg
À1
inoculum) was evaluated by Ford et al. (2007). Furthermore, Schmidt et al. (2005)
observed a clear link with the amount of T. Versicolor fungal inoculums used and
colonization of fungal cultures in soil bioaugmented for bioremediation.
Soil contaminated with PCP biodegradation by immobilized WRF
Anthracophyllum discolor and P. chrysosporium on wheat straw was studied by
Rubilar et al. (2011). In the presence of a contaminant, high-level MnP activities and
fungal biomass was recognized in their studies. Moreover, 75% of pollutant degradation was consequently identified in immobilized fungal cultures on wheat grains in
the soil samples (Rubilar et al. 2011). Efficient bioremediation of atrazine by
immobilized A. discolor on formulating pelletized support was evaluated by Elgueta
et al. (2016). The list of recent studies on the bioremediation of xenobiotics by white
rot fungi is given in Table 4.4.
4.4.1 LE Involved in Bioremediation of Xenobiotic
Compounds
WRF is the most efficient organisms to secrete LMEs (LAC, MnP, LiP) for the
mineralization of lignin polymer. Oxidative and non-specific nature of these
enzymes shows the potential application in the bioremediation of environmentally
toxic pollutants. Among these ligninolytic enzymes laccase enzyme plays a major
role in the oxidation of various xenobiotic compounds and also there are several
4 Influence of Xenobiotics on Fungal Ligninolytic Enzymes
109