[Enhancement of laccase activity by combining white rot fungal strains].

The method of combining white rot fungal strains was used to enhance laccase activity, and the interaction mechanism between strains was also studied. The laccase activity of combined fungi of strain 55 (Trametes trogii) and strain m-6 (Trametes versicolor) were 24.13 and 4.07-fold higher than that of strain 55 and strain m-6, respectively. No inhibitory effect was observed when the two strains were co-cultivated. On plate cultivation, there was hyphal interference in the contact area, where laccase activity was the highest followed by brown pigmentation. In liquid cultivation, strain m-6 played much more important role on enhancement of laccase activity, and the laccase activity of strain 55 by adding strain m-6 was 7.03-fold higher than that of strain m-6 by adding strain 55, furthermore, filter sterilized- and high temperature autoclaved-extracellular substances of strain m-6 could also stimulate strain 55 to excrete more laccase, which led to 6.79-fold and 4. 60-fold increase in laccase activity by adding 20 mL, respectively. The native staining results of Native-PAGE showed that the types of laccase isozymes were not changed when strains were co-cultured, but the concentration of three types increased.

[Isolation of PVA-degrading symbiotic bacteria and examination of degradation characters].

From printing and dyeing actived sludge, PVA- degrading symbiotic bacteria was isolated. The symbiotic bacteria is composed of B1 and B2. During PVA biodegradation, B1 produces a certain growth factor for B2, B2 produces PVA-degrading enzyme. The PVA-degrading characters of the symbiotic bacteria are examined. When the concentration of PVA was 0.1, 0.5, 1g/L respectively,more than 80% of PVA was degradated after 7days. During the treatment of the dyeing and printing wastewater, when the temperature was 30 degree C ,the removal of COD(Cr) was 69.75%, the proper treating time was 12h.