Screening, Evaluation and Phylogenetic Identification of Laccase from Trichoderma Species and its Application in Bisphenol Degradation

Genus Trichoderma was explored to find out the laccase activity by submerge cultivation. In this work, ten different Trichoderma species were isolated from soil samples collected from different sources. These biocontrol fungi were identified by internal transcribed spacer (ITS) sequences. Guaiacol (0.04 %) as an enzyme substrate in Plate medium was used for the selection of maximum laccase enriched Trichoderma species. This activity was also evaluated by liquid submersion (flask medium). The absorbance of broth contained laccase was measured by spectrophotometer (450 nm). Different Trichoderma species were explored to evaluate the strongest laccase potentials. The proficient Trichoderma species was T. atroviride yield maximum laccase (2.62 U/mL). Trichoderma cremeum and T. longipile was medium in laccase potency, while T. beinartii showed weak laccase secretion ability. Laccase of T. atroviride was purified by SDS-PAGE and determined the molecular weight (57 kDa). The laccase confirmation was achieved by amino acid sequences and constructed the phylogenetic tree for authenticity. The laccase secreted by T. atroviride exhibited good potential to degrade the toxic phenolic compound (BPA) efficiently, after 1-h reaction of 5 μg purified laccase and 0.5 mmol/L ABTS mediator at 28 °C (pH 5.5). The degradation rate was reached 98.2 %, which demonstrated the great potential to degrade the bisphenol A.