pH值对白腐真菌液体培养基抑制杂菌效果的影响研究

应用摇瓶试验研究了不同初始pH值对白腐真菌Phanerochaete chrysosporium液体培养基在非灭菌环境抑制杂菌效果的影响.结果表明,当采用Phanerochaete chrysosporium孢子作为种子在非灭菌环境进行培养时,初始pH值为3.6和4.4的液体培养基在培养第1d仅感染酵母菌,而初始pH值为5.6的液体培养基不仅感染了酵母菌而且还感染了细菌;正是由于非灭菌环境培养体系感染杂菌,使得后续Phanerochaete chrysosporium对活性艳红K-2BP的脱色能力大大降低甚至丧失;而采用灭菌环境培养Phanerochaete chrysosporium,非灭菌环境脱色活性艳红K-2BP的方法却获得了较好的脱色效果,3种初始pH值的氮限制液体培养基培养出的Phanerochaete chrysosporium对活性艳红K-2BP 45h的脱色率均在70%以上,接近或超过灭菌环境的结果,其中初始pH值为4.4的液体培养基培养的Phanerochaete chrysosporium在非灭菌环境对活性艳红K-2BP的脱色效果最好,其24h的脱色率达到80%以上.尽管3种pH液体培养基在脱色过程中也同样感染了杂菌,但与非灭菌环境培养体系相比含量很少,没有影响脱色效果.因此,可以得出低pH值(pH=3.6,pH=4.4)氮限制培养基虽然在一定程度上可以抑制细菌,但是却不能抑制酵母菌;当在非灭菌环境使用Phanerochaete chrysosporium脱色活性染料时,Phanerochaete chrysosporium只有在灭菌环境培养至菌丝体形成并在整个系统占优势,才能获得较高的脱色效果.

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.