Screening and cloning ligninolytic strain and cellulase gene expression
木质素降解菌的筛选及其纤维素酶基因克隆表达研究

In order to effectively biodegrade lignin, lignin-degrading bacteria screening and fiber material treatment with cellulase were conducted. Eight strains producing positive reaction were selected by detecting the growth status and enzyme activity of 14 strains on the media with guaiacol, aniline and tannic acid. The strains were re-screened by using the ratio of Klason lignin degradation rate to holocellulose degradation rate (SF index) as indicator. In comparison to Phanerochaete chrysosporium RP78 and P. chrysosporium BKM-F-1767, strains Pleurotus ostreatus Po 10969 and Ganoderma applanatum WP1 were selected because their higher growth rate, enzyme secretion and degradation ability. Meanwhile, cellulase gene (egl2) was cloned, expressed and enzyme activity determined. Reducing-sugar produced by different treatments was determined by soaking the materials with crude enzymes solution. The results show that sugar-reduction ability of the materials is in the order of: Juncao Penniusetum sinese Roxb treated with NaClO2>Juncao P. sinese Roxb treated with Po10969>untreated Juncao P. sinese Roxb. Research on white rot fungus is significant for making full use of plant resources, safe degradation of pollutants and fuel ethanol exploration, as well as the sustainable development of eco-agriculture in China.