title: Degradation of aflatoxin B(1) by fungal laccase enzymes.
abstract: The enzymatic degradation of aflatoxin B(1) (AFB(1)) by white rot fungi through laccase production was investigated in different liquid media. A significant (P<0.0001) correlation was observed between laccase activity and AFB(1) degradation exhibited by representatives of Peniophora and Pleurotus ostreatus cultivated in minimal salts (MSM) (r=0.93) and mineral salts - malt extract (MSB-MEB) (r=0.77) liquid media. Peniophora sp. SCC0152 cultured in MSB-MEB liquid medium supplemented with veratryl alcohol and sugarcane bagasse showed high laccase activity (496U/L), as well as 40.45% AFB(1) degradation as monitored using high performance liquid chromatography. P.ostreatus St2-3 cultivated in MSM liquid medium supplemented with veratryl alcohol resulted in laccase activity of 416.39U/L and 35.90% degradation of AFB(1). Aflatoxin B(1) was significantly (P<0.0001) degraded when treated with pure laccase enzyme from Trametes versicolor (1U/ml, 87.34%) and recombinant laccase produced by Aspergillus niger D15-Lcc2#3 (118U/L, 55%). Aflatoxin B(1) degradation by laccase enzyme from T. versicolor and recombinant laccase enzyme produced by A. niger D15-Lcc2#3 coincided with significant (P<0.001) loss of mutagenicity of AFB(1), as evaluated in the Salmonella typhimurium mutagenicity assay. The degradation of AFB(1) by white rot fungi could be an important bio-control measure to reduce the level of this mycotoxin in food commodities.
authors.affiliation: Department of Microbiology, University of Stellenbosch, Matieland, 7602, South Africa.
authors.forename: J F
authors.initials: JF
authors.lastname: Alberts
authors.forename: W C A
authors.initials: WC
authors.lastname: Gelderblom
authors.forename: A
authors.initials: A
authors.lastname: Botha
authors.forename: W H
authors.initials: WH
authors.lastname: van Zyl
mesh_terms: D016604:Aflatoxin B1 / Q000378:metabolism*; D000898:Antibiosis; D001487:Basidiomycota / Q000201:enzymology* / Q000378:metabolism; D001592:Benzyl Alcohols / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D003470:Culture Media / Q000737:chemistry; D005519:Food Preservation / Q000379:methods*; D042845:Laccase / Q000096:biosynthesis / Q000378:metabolism*; D020076:Pleurotus / Q000201:enzymology / Q000378:metabolism; D020072:Polyporales / Q000201:enzymology / Q000378:metabolism; D055454:Trametes / Q000201:enzymology / Q000378:metabolism
chemical_list: D001592:Benzyl Alcohols; D003470:Culture Media; D002482:Cellulose; C027433:bagasse; D016604:Aflatoxin B1; D042845:Laccase; C042197:veratryl alcohol