Laccases are generating a great interest clue to their biotechnological potential They are multicopper oxidases that catalyze aromatic and non-aromatic compounds, concomitantly with molecular oxygen reduction to water. In this work was selected the encoding gene for POXA IB laccase from the fungus Pleurotus ostreatus. This gene was optimized for codon use in Pichia pastoris, GC content, and regions generating secondary structures. Laccase proposed computational model, and their interaction with ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)] substrate was evaluated by molecular docking. After using a Plackett-Burman Design followed by a One Factor it was obtained a laccase activity of 1,343.52 ± 40.3 UL'1 at 16Sh of culture in a 500 inL shake-flask. Tire concentrated supernatant, containing the POXA IB enzyme, remained stable between 10 and 50°C and retained over 70% residual enzymatic activity at 60°C and 50% at 70°C. Besides the enzyme was more stable at pH 4 ± 0.2 with a residual activity greater than 90%. The lowest residual activity of 60% was obtained at pH 10 ± 0.2. Furthermore, kinetic parameters were Vmax of 3.163 x 102 mM s1 and Km of 1.720 mM. The decolorization of synthetic black liquor at 5 days of treatment was 19, 53 y 59%, for 10, 5 y 1% (v/v) liquor concentrations, and the DQO removal 5, 30 y 53%, respectively, with a lacase activity of 1399, 1346 y 1327 UL1 for each different concentration. All this information together can be considered as important findings in light of recombinant enzyme expression system utility for environmentally friendly designed expression systems, because of the wide range of substrates that laccases can transform. Contributing to a great gamut of products in diverse settings: industry, clinical and chemical use, and environmental applications.