Thermo stable tyrosinase purified from Pleurotus djamor grown in biomimetic calcium carbonate: A biological strategy to industrial waste remediation

A novel, neutral and heat-tolerant tyrosinase produced from Pleurotus djamor (P. djamor) using biomimetic calcium carbonate which was further used for the biodegradation of the phenolic waste of industrial effluents. Carbon-dioxide was sequestered/captured into calcium carbonate (CaCO3) using carbonic anhydrase (2.1 U/mg protein) of Oceanobacillus with sequestration capacity as 24.7 CaCO3/mg protein in 25 s. This CaCO3 was used as a substrate for cultivation of P. djamor (a mushroom) which was the potential source of tyrosinase. Mushroom tyrosinase was purified up to 51.7 folds purity which shown a molecular weight similar to 90 kDa on SDS-PAGE. The optimal thermal and pH activity of the tyrosinase was observed at 50 degrees C and 7.0, respectively. The tyrosinase was stable within a pH range of 6.0-8.0, temperature 35 degrees C-55 degrees C and showed high substrate specificity for L-DOPA. Tyrosinase activity was drastically enhanced by Cu2+, Ca2+ and Mn2+ metal ions. K+ ions were also found to inhibit the tyrosinase activity up to the moderate level. Mushroom tyrosinase was used to degrade phenol from industry effluents with 90% removal in 6 h. Extracellular nature as well as tyrosinase stability in the extreme conditions (temperature, pH, and presence of heavy metals) makes it preferable candidate for phenol bioremediation from industrial effluents. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

A novel, neutral, and heat-tolerant tyrosinase produced from Pleurotus djamor was utilized for the biodegradation of phenolic waste in industrial effluents. Carbon dioxide was sequestered into calcium carbonate using carbonic anhydrase of Oceanobacillus, which was then used as a substrate for cultivating tyrosinase-producing mushroom. The mushroom tyrosinase showed high stability and efficiency in degrading phenol from industrial effluents, making it a promising candidate for bioremediation applications.