Production of a novel laccase from Paraphoma Sp
By using a laccase-secretion indicator for screening laccase-producing microorganisms, a novel laccase-producing strain was isolated and identified as Paraphoma sp. strain GZS18, it produced increased laccase and mycelia at 34 °C. Further investigations showed that the production of laccase by Paraphoma sp. GZS18 was greatly enhanced by less toxic inducers copper sulphate and methyl orange. Copper sulphate and methyl orange were added into the cultivation medium at 12 and 60 h, respectively, and the maximum laccase production was obtained. Through Plackett–Burman design and response surface methodology, we obtained the optimum production conditions as follows: methyl orange, 39.90 μM; addition time of copper sulphate, 11.95 h; addition time of methyl orange, 51.40 h. Under the above conditions, the experimental value of laccase production was 12,250.76 U/L. The extracellular laccase from Paraphoma sp. GZS18 was purified to homogeneity, which showed a molecular mass of 75 kDa. N-terminal amino acid sequences was AXaVSVASREMT.
