Biodegradation of the Pyrethroid Pesticide Gamma-Cyhalothrin by Fungi from a Brazilian Cave

The extensive use of pesticides promoted the need for bioremediation methods, including for pyrethroids. Therefore, biodegradation of gamma-cyhalothrin by fungi from a Brazilian cave known as Gruta do Catão (São Desidério, Bahia, Brazil) was investigated. Experiments were conducted with Aspergillus ustus CBMAI 1894, Talaromyces brunneus CBMAI 1895, and Aspergillus sp. CBMAI 1926 in 2% malt liquid medium with 300 mg L^-1 gamma-cyhalothrin (25 °C, 130 rpm, 21 days, pH 7.0). All strains biodegraded this insecticide, and the most efficient biocatalyst was A. ustus CBMAI 1894 with 50% biodegradation, even though reduced mycelial mass was observed in the presence of gamma-cyhalothrin. A three factor Box-Behnken design was carried out. Temperature and pesticide concentration influenced biodegradation, whereas pH was non-significant. In conclusion, cave fungi can be explored for bioremediation, and future studies should focus on understanding the enzymatic apparatus, physiology, and genetics behind these microorganisms, which can present unique properties for biotechnological applications.

Keywords:
Aspergillus ustus ; Talaromyces brunneus ; bioremediation; cyhalothrin; insecticide; contamination