Efficiency of laccase production in a 65-L air-lift reactor for potential green industrial and environmental application

Laccase is one of the most useful green enzymes for cleaner industrial application and environmental protection. It is necessary to produce laccase with known composition of its commercial style at low production cost in an efficient way. In this study, the efficiency of laccase production by Pycnoporus sp. SYBC-L3 in a 65-L air-lift reactor was evaluated and the main extracellular proteins were identified. The highest laccase activity approximated 72,000 U/L after 6 days' cultivation. Using nano-LC-MS/MS protein identification technology, 22 different peptide fragments were identified matching sequences in different proteins with laccase as the predominant extracellular one. The crude laccase exhibited high catalytic activity at temperatures ranging from 0 degrees C to 100 degrees C at an acidic condition, with respective relative activity of 40% at 0 degrees C and 80% at 100 degrees C. The crude laccase was found to be very thermal stable, with half-lives of 4 h, 6.5 h and 10 h at 70 degrees C, 60 degrees C and 50 degrees C, respectively. The crude laccase still retained approximately 85% of its initial activity after one year of storage at room temperature. These results showed that laccase can be effectively produced by Pycnoporus sp. SYBC-L3 in air-lift reactor at larger scale and has great potential for industrial production and applications. (c) 2012 Elsevier Ltd. All rights reserved.