理化因素对锰细菌Arthrobacter chlorophenolicus MN1409氧化Mn^(2+)的影响

Physicochemical factors for affecting the efficiency of Arthrobacter chlorophenolicus MN1409 on manganese oxidation

Arthrobacter chlorophenolicus MN1409是1株分离自锰矿样品的高效锰氧化细菌。为了建立该菌株氧化Mn2+的适宜条件,研究了接种量、装液量、摇床转速、温度、pH值、Fe2+初始质量浓度和Mn2+初始质量浓度等理化因素对其锰氧化效率的影响。结果表明,接种量、装液量、转速和Mn2+初始质量浓度在一定范围内变化对锰氧化率影响不大;而温度、pH值和Fe2+初始质量浓度变化对锰氧化率有较大影响。当接种量为4%,装液量为60 mL,温度为25℃,摇床转速为100r/min,pH值为7,且有一定的Fe2+存在时,Arthrobacter chlorophenolicusMN1409对锰的氧化效率最高。

The physicochemical factors for affecting the manganese oxidation efficiency of an manganese oxidizing bacteria named Arthrobacter chlorophenolicus MN1409 which was isolated from manganese ore sample were studied.The identified factors include inoculum volume,liquid volume,temperature, shaking speed,pH as well as the concentration of Fe2＋and Mn2＋.The results showed that there was no significant effect on the biological manganese oxidation rate and chemical manganese oxidation rate during 2%-10% inoculum volumes.4% inoculum volume was the optimum condition according to its highest total manganese oxidation rate.Similarly,biological and chemical manganese oxidation rate have no significant difference for the liquid volume ranging from 50 mL to 100 mL in 250 mL triangular flask,the highest total manganese oxidation rate occurred in 60 mL liquid volume.Nevertheless,temperature showed an positive effect on manganese oxidation rate.By increasing the temperature from 15 ℃ to 35 ℃,highest biological and chemical manganese oxidation rate could be reached at 25 ℃ and 35 ℃,respectively,plus the total oxidation rate could achieved 81.52% as well in 35 ℃.In addition,the effect of shaker speed on manganese oxidation efficiency（MOE） showed that the oxidation rates were similar for rotation speed within 100 r/min and 180 r/min in which the optimum value is 100 r/min.The pH experiments indicated that neutral pH was conductive to biological oxidation.Chemical oxidation rate and its ratio in total manganese oxidation rate increased sharply along the pH increment.The results also showed that the initial concentration of Fe2＋has a positive impact on MOE where 81% of MOE could be achieved when the Fe2＋concentration was 100 mg/L.Nevertheless,the initial concentration of Mn2＋has not substantial effect on MOE.The total manganese oxidation rates reached 85%-90% regardless the initial concentrations of Mn2＋,i.e.5-30 mg/L.Under the optimal conditions,the maximum removal rate of Mn2＋by the bacteria Arthrobacter chlorophenolicus MN1409 was above 85.6%.