Xie Shan, Liu Junxin, Li Lin, Qiao Chuanling
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
J Environ Sci (China). 2009;21(1):76-82. doi: 10.1016/s1001-0742(09)60014-0.
To enhance the removal efficiency of malathion in the wastewater from organophosphate pesticide mill, a bacterium, Acinetobacter johnsonii MA19, that could degrade malathion with cometabolism was isolated from malathion-polluted soil samples using enrichment culture techniques. Four kinds of additional compounds, sodium succinate, sodium acetate, glucose, and fructose were tested to choose a favorite carbon source for the cometabolism of strain MA19. The results showed that sodium succinate and sodium acetate could promote malathion biodegradation and cell growth. The investigation results of the effects of sodium succinate concentrations on the malathion biodegradation indicated that the more sodium succinate supplied resulted in quick degradation of malathion and fast cells multiplied. Zero-order kinetic model was appropriate to describe the malathion biodegradation when the concentration of sodium succinate was more than 0.5144 g/L. The degradation rate constant (K) reached the maximum value of 3.5837 mg/(L x h) when the mass ratio of sodium succinate to malathion was 128.6 mg/mg. The aquatic toxicity of the malathion was evaluated using the test organism, Limnodrilus hoffmeisteri. The data obtained suggested that the toxicity of malathion could be ignored after 84 h biodegradation. Our result demonstrates the potential for using bacterium A. johnsonii MA19 for malathion biodegradation and environmental bioremediation when some suitable conventional carbon sources are supplied.
为提高有机磷农药厂废水中马拉硫磷的去除效率，采用富集培养技术从马拉硫磷污染的土壤样品中分离出一株能通过共代谢降解马拉硫磷的细菌——约翰逊不动杆菌MA19。测试了琥珀酸钠、醋酸钠、葡萄糖和果糖四种外加化合物，以选择菌株MA19共代谢的最佳碳源。结果表明，琥珀酸钠和醋酸钠能促进马拉硫磷的生物降解和细胞生长。琥珀酸钠浓度对马拉硫磷生物降解影响的研究结果表明，供应的琥珀酸钠越多，马拉硫磷降解越快，细胞增殖越快。当琥珀酸钠浓度大于0.5144 g/L时，零级动力学模型适合描述马拉硫磷的生物降解。当琥珀酸钠与马拉硫磷的质量比为128.6 mg/mg时，降解速率常数（K）达到最大值3.5837 mg/(L·h)。以霍甫水丝蚓为受试生物评价了马拉硫磷的水生毒性。所得数据表明，生物降解84 h后，马拉硫磷的毒性可忽略不计。我们的结果表明，当提供一些合适的传统碳源时，利用约翰逊不动杆菌MA19进行马拉硫磷生物降解和环境生物修复具有潜力。
