Mycoremediation of Benzo[a]pyrene by Pleurotus ostreatus in the presence of heavy metals and mediators.
Benzo[a]pyrene is considered as a priority pollutant because of its carcinogenic, teratogenic and mutagenic effects. The highly recalcitrant nature of Benzo[a]pyrene poses a major problem for its degradation. White-rot fungi such as Pleurotus ostreatus can degrade Benzo[a]pyrene by enzymes like laccase and manganese peroxidase. The present investigation was carried out to determine the extent of Benzo[a]pyrene degradation by the PO-3, a native isolate of P. ostreatus, in the presence of heavy metals and ligninolytic enzyme mediators. Modified mineral salt medium was supplemented with 5 mM concentration of different heavy metal salts and ethylenediaminetetraacetic acid. Vanillin and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (1 and 5 mM) were used to study the effect of mediators. Results indicated that P. ostreatus PO-3 degraded 71.2 % of Benzo[a]pyrene in the presence of copper ions. Moderate degradation was observed in the presence of zinc and manganese. Both biomass formation and degradation were severely affected in the presence of all other heavy metal salts used in the study. Copper at 15 mM concentration supported the best degradation (74.2 %), beyond which the degradation progressively reduced. Among the mediators, 1 mM 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate) supported 78.7 % degradation and 83.6 % degradation was observed under the influence of 5 mM vanillin. Thus, metal ion like copper is essential for better biodegradation of Benzo[a]pyrene. Compared to synthetic laccase mediator like 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate), natural mediator such as vanillin may play a significant role in the degradation of aromatic compounds by white-rot fungi.
Department of Microbiology, Karpagam University, Coimbatore, 641021, Tamil Nadu, India. sourav3011@rediffmail.com.
Sourav
S
Bhattacharya
Department of Microbiology, Genohelix Biolabs, Centre for Advanced Studies in Biosciences, Jain University, Bangalore, 560019, Karnataka, India.
Arijit
A
Das
Department of Biotechnology, Genohelix Biolabs, Centre for Advanced Studies in Biosciences, Jain University, Bangalore, 560019, Karnataka, India.
Kuruvalli
K
Prashanthi
Department of Microbiology, Karpagam University, Coimbatore, 641021, Tamil Nadu, India.
Muthusamy
M
Palaniswamy
Department of Microbial Biotechnology, Bharathiar University, Coimbatore, 641046, Tamil Nadu, India.
Jayaraman
J
Angayarkanni
Benzo[a]pyrene; Degradation; Heavy metals; Mediators; Pleurotus ostreatus