[Effect of pH on suppressing the growth of other bacteria and fungi in culturing Phanerochaete chrysosporium in liquid medium].

Effect of different pH value on suppressing the growth of other bacteria and fungi in culturing Phanerochaete chrysosporium in liquid medium under non-sterile were investigated in agitated Erlenmeyer flasks. Results showed that nitrogen-limited liquid medium with pH3.6 and pH4.4 were contaminated only by yeast fungi when the Phanerochaete chrysosporium was incubated with spore inoculation under non-sterile condition for one day; however, nitrogen-limited liquid medium with pH5.6 was contaminated not only by yeast, but also by bacteria. These contaminated yeast and bacteria reduced the dye decolorizing ability of Phanerochaete chrysosporium . If after the Phanerochaete chrysosporium was incubated under sterile condition for 5 days, it can decolorize over 70% of the reactive brilliant red K-2BP within 45 hours under non-sterile condition, and this removal rate was close to or even higher than that under sterile condition. Phanerochaete chrysosporium cultured in the liquid medium with pH4.4 have the best decolorizing effect under non-sterile condition, and can decolorize up to 80% of the reactive brilliant red K-2BP in 24 hours. In additions, it was observed that by using the Phanerochaete chrysosporium incubated in above nitrogen-limited liquid medium with different pH under sterile condition for 5 days, the system were also contaminated by the other bacteria and yeast during decolorizing reactive brilliant red K-2BP under non-sterile condition, but the amount of these bacteria and yeast in liquid medium were too little to influence the Phanerochaete chrysosporium decolorizing reactive brilliant red K-2BP. So that, when Phanerochaete chrysosporium was used to decolorize reactive dyes under non-sterile condition, the incubation of Phanerochaete chrysosporium must be operated under sterile condition in order to achieve the higher decolorization.