3株细菌降解木质素的条件调控研究

Cultural condition regulations for three lignin degrading bacteria

采用苯胺蓝和RB亮蓝平板对从三国吴简腐蚀斑中分离得到的3株细菌Acinetobacter sp.B-2,Pandoraea sp.B-6和Novosphingobium sp.B-7进行脱色试验,考察这3株细菌在液体培养条件下的木质素降解性能,并对其木质素降解条件的调控进行研究,初步确定这3株菌适宜的降解条件。研究结果表明:这3株细菌具有使苯胺蓝和RB亮蓝染料脱色的能力,能够产木质素降解酶;这3株细菌的木质素降解速率较快,第5天木质素的降解基本趋于稳定;菌株适宜的降解条件如下:对Acinetobacter sp.B-2,氮源为硝酸铵,氮源浓度为0.01 mol/L,培养温度为30℃,初始pH=7.0,摇床转速为120 r/min;对Pandoraea sp.B-6,氮源为磷酸氢二铵,氮源浓度为0.03 mol/L,培养温度为30℃,初始pH=7.0,摇床转速为120 r/min;对Novosphingobium sp.B-7,氮源为硝酸铵,氮源浓度为0.01 mol/L,培养温度为30℃,初始pH为5.0,摇床转速为120 r/min。在适宜的降解条件下,这3株细菌第3天的木质素降解率均可达到30%～35%。

The decolorizing reactions of three bacteria were studied through Azure-B and Remazol Brilliant Blue dye plate,which were isolated from erosive bamboo slips of Kingdom Wu,identified as Acinetobacter sp.B-2,Pandoraea sp.B-6 and Novosphingobium sp.B-7,respectively.The lignin degrading characteristics of three bacteria were investigated in the liquid medium.The effects of culture conditions on lignin degrading ability of the three bacteria were also studied,and the appropriate culture conditions were determined.The results show that three bacteria can decolorize Azure-B and Remazol Brilliant Blue dye and produce ligninolytic enzyme.Three bacteria can degrade lignin very well with a relatively high degrading rate,and the plateau of degradation is observed after 5 d incubation.Appropriate culture conditions for Acinetobacter sp.B-2 are achieved as follows： NH4NO3 as nitrogen source,0.01 mol/L of nitrogen source concentration,30 ℃ of temperature,the initial pH=7.0,120 r/min of rotation speed.The appropriate culture conditions for Pandoraea sp.B-6 and Novosphingobium sp.B-7 are similar to that for Acinetobacter sp.B-2,and NH4H2PO4 as nitrogen source and 0.03 mol/L of nitrogen source concentration for Pandoraea sp.B-6,the initial pH=5.0 for Novosphingobium sp.B-7,respectively.In addition,the degrading rates of three bacteria can reach 30%-35% after 3 d incubation under appropriate degrading conditions.