Screening and evaluation of laccase produced by different Trichoderma species along with their phylogenetic relationship.

Laccases have high biotechnological potential in industries since they catalyze the oxidation of many chemical compounds. The production of laccases by fungi has been extensively studied due to their secretion of enzymes and rapid growth using cheap substrates. Trichoderma; the versatile fungal genus includes species of great biotechnological value and considered as a magnificent industrial cell factory of enzymes. In this study, 10 Trichoderma species were screened for laccase enzyme production by submerged cultivation. The studied species were identified by internal transcribed spacer (ITS) gene sequences. Guaiacol (0.04%) as an enzyme substrate in plate medium was used for the selection of maximum laccase-enriched Trichoderma species by formation of visual color halo intensity. This activity was evaluated by liquid submersion (flask medium) also. The absorbance of laccase contained broth was measured by a spectrophotometer (450 nm). The highest laccase production was obtained by T. atroviride (2.62 U/mL). Trichoderma cremeum and T. longipile showed medium laccase potency, while T. beinartii exhibited weak laccase secretion ability. Laccase from T. atroviride was purified by SDS-PAGE and the molecular weight was determined (57 kDa). The laccase was confirmed by their respective amino acid sequences, and the phylogenetic tree was constructed for further analysis.