一株黄杆菌及其粗酶液对芘降解的动力学特征研究  

The study of kinetic properties on degradation of pyrene by a flavobacterium sp. and its enzyme

作　　者：聂麦茜[1] 吴蔓莉[1] 王晓昌[1] 林玲[1] 王蕊[1] 王学选 

机构地区：[1]西安建筑科技大学环境与市政工程学院,西安710055 [2]西安市政建设监理咨询公司监理部,西安710055

出　　处：《环境科学学报》2006年第2期181-185,共5页Acta Scientiae Circumstantiae

基　　金：陕西省教育厅科研计划项目(自然科学专项)(No.04JK157)~~

摘　　要：实验研究了一株黄杆菌FCN2对芘降解的动力学特性,以及该菌株对芘的好氧氧化具有催化作用的酶的分布特征、芘在胞内酶存在下酶促降解的动力学特征.研究结果表明,本实验室经驯化、筛选、分离所得的FCN2菌株对芘有良好的降解性能;反应后10h内,降解反应近似表现为一级动力学特性,且随着芘初始浓度的增加,反应速度加快;当芘的初始浓度达到200mg·L-1时,菌体的降解活性被抑制;菌体的初始浓度越大,芘的降解转化速率越快;当菌量达到3.0×108CFUs·mL-1(CFUscolony-formingunits)时,芘的降解转化速度不再随着起始菌量的增加而增加.在本实验的好氧条件下,最适初始菌量为1.0×108～2.0×108CFUs·mL-1范围内.FCN2菌株对芘好氧降解起催化作用的活性酶为胞内酶,它对芘降解的催化作用迅速、有效,短时间内即达到分解平衡;胞内酶最适pH值为5,在pH5.0～6.0之间均有较高的催化活性;胞内酶最适温度为32℃,在30～50℃之间能保持较高的催化活性;粗提胞内酶催化芘的好氧降解过程中,米氏常数较小,为1×10-4mol·L-1,最大反应速率为2×10-6mol·L-1·min-1,说明酶与芘的亲和力大.The kinetic properties of biodegradation of pyrene by aflavobaeterium strain and its coarse endoenzyme were studied, and the distribution of the enzyme which plays main rule in degradable and transforming pyrene was investigated. As a result, theflavobaeterium strain FCN2 isolated was found to be an effective strain for degrading pyrene. The degradable process behaved as a pseudo -first - order reaction within a period of/Oh reaction time, and the reaction rate increased with the original concentrations of pyrene and biomass. However, the reaction was almost completely restrained as the original concentration ot pyrene reached 200 mg· L ^-1. As original biomass was higher than 2.0 × 10^8 CFUs· mL^-1, there was ao longer any increase of reaction rate under an aerobic condition and the suitable biomass was from 1.0 × 10^8 to 2.0 10^8 CFUs· mL^ -1 . The active enzyme which played the main rule in degradable pyrene was the endoenzyme of theflavobacterium strain FCN2. The catalysis action of the endoenzyme was highly effective, so that the reaction reached equilibrium state quickly. The suitable pH was 5, 0 and the suitable temperature was 32℃ though the endoenryme was still active within pH 5.0 - 6. 0 and 30 - 50℃. The Michaelis constant Km was found to be 1 × 10^-4 mol·L^- 1 , and the maximum degradation rate of pyrene under the catalysia of the endoenzyme was 2 × 10^-6 tool·L^-1· min^-1 This indicated that the affinity of the endoenzyme to nvrene was great.

关 键 词：黄杆菌FCN2 芘 生物降解 酶促降解 米氏常数 

分 类 号：X172[环境科学与工程—环境科学]