[Isolation, identification and enzymological characterization of a new fungal with high laccase production from agricultural waste composting].

A new fungal strain with high laccase production was isolated from the agricultural waste composting. It was identified as Hypocrea lixii based on morphological analysis and ITS sequence. The partial laccase gene of the new strain was successfully amplified using the primer pair Cu1AF and Cu2R. After purification and cloning of the PCR product, a 148 bp fragment of laccase gene was obtained. The laccase activity of the strain reached a peak value of 67.5 U x mL(-1) in liquid medium. The molecular mass of the purified laccase was determined to be about 60 x 10(3). The optimum temperature and pH for enzyme activity were 35 degrees C and 4.0, respectively. The half-time of the enzyme was more than 1 h at 60 degrees C. Under standard assay conditions, K(m) values was 1.00 mmol x L(-1) towards ABTS. Laccase activity was inhibited by several metal ions, such as Na+, Fe2+, Fe3+, Pb2+ and Zn2+. This strain has a good potential for application as a bioaugmentation strain in the agricultural waste composting system.