Enhanced laccase activity in Trametes versicolor (L.: Fr.) Pilat by host substrate and copper

Laccases are appealing biocatalysts for various industrial utilizations. The fungus Trametes versicolor (L.: Fr.) Pilat causes white rot in wood and has been identified as an important fungal laccase producer. To investigate laccase production and activity in T. versicolor, the native isolate was collected from the host (Quercus castaneifolia) in the forests of Guilan province, northern Iran, and then purified and identified using the molecular marker. Its ability to produce laccase enzyme in the presence of different plant substrates including sawdust and wood chips of oak, poplar, and pine was evaluated. Also, the effect of copper as an enzyme inducer was investigated in vitro. The results showed that adding the wood to the culture medium increased laccase production, and among these, oak sawdust had the greatest effect, a 1.7-fold increase from that in the control (4.8 u/l vs. 2.8 u/l). Also, the enzyme extraction time effect on the optimal recovery yield showed that the 5-h enzyme extraction cycle resulted in the highest yield of the enzyme (18.97 u/l). Moreover, adding different concentrations of copper to the fungal culture medium increased the production of laccase, and the highest amount of enzyme (92.04 u/l) was obtained with 3.5 mM of CuSO4 along with oak sawdust. Based on the results, the addition of host wood sawdust (oak in this work) and copper particles together stimulates the fungal growth and the laccase production during submerged cultivation of T. versicolor. Therefore, it would be a safe and cheap strategy for the commercial production of laccase by filamentous fungi.

Automated summary

This study investigated the production and activity of laccase in Trametes versicolor. The results showed that adding oak sawdust as a substrate and copper as an enzyme inducer significantly increased laccase production. This finding suggests that using oak sawdust and copper could be a cost-effective and safe strategy for commercial laccase production.