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Guo, H., Lin, C., Wang, S., Jiang, D., Zheng, B., Liu, Y., and Qin, W. (2017). "Characterization of a novel laccase-producing Bacillus sp. A4 and its application in Miscanthus degradation," BioRes. 12(3), 4776-4794.


Bacillus sp. A4 exhibiting laccase production was isolated from forest soil. Its laccase secreted into a LB medium exhibited a maximum activity of 3.9 U mg-1 protein at the optimal temperature (37 °C) and pH (6.0). The purified laccase of Bacillus sp. A4 demonstrated a low molecular mass of 33 kDa, and its optimal temperature and pH were 40 °C and 4.6, respectively, when using ABTS as a substrate. The activity of the purified laccase was significantly increased in the presence of Cu2+, methanol, and ethanol, but it was totally inhibited by L-cysteine. The laccase production of this strain was markedly stimulated when the strain was incubated with 0.5% different lignocellulosic biomasses. The highest activity of laccase (22.6 U mg-1 protein) was obtained in using algal biomass. This new strain efficiently decreased the lignin content of lignocellulose biomasses after 9 d of incubation at 37 °C, especially lignin from grasses. Further analysis showed that, compared to that of all tested biomasses, the new strain was a more efficient decomposer of the lignin of Miscanthus, which exhibited much more lignin loss and cell wall structure destruction in a short span of time. Therefore, the potential use of this strain could be advantageous for using lignin in Miscanthus for industrial processes.

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