海洋酵母在近海养殖水体BOD生物传感器中响应行为分析

On the efficient microbial membrane with the marine yeast applied in BOD sensor for the in-shore seawater fishery

针对海洋环境高盐、高压和低BOD的检测特点,筛选出3株海洋酵母,分别采用玻璃纤维滤纸将其固定化,安装于Cleark氧电极制备了BOD传感器的微生物膜电极。通过比较3种微生物膜电极的底物适用范围、线性范围及其测量结果的准确度和精密度,选择对数生长期的汉逊德巴利海洋酵母Debaryomyces hanseniiHXY-09构建的微生物膜电极作为试验电极。进一步以对近海养殖水体BOD的检测结果有显著影响的待测样品底液pH值、电极工作温度和底液离子浓度3个因素为自变量,以传感器的响应电流为响应值,设计3因素3水平响应面分析试验,通过MATLAB6.5.0软件拟合二次曲线确定汉逊德巴利海洋酵母Debaryomyces hanseniiHXY-09构建的微生物膜电极的最适工作条件为:待测样品pH值7.7,电极工作温度20℃,样品底液离子浓度40mmol/L。在该条件下检测结果的相对误差从4%减小至0.5%,初步证实了该生物传感器在实验室条件下对近海养殖水体BOD检测具有较好的精密度和准确度。

The paper takes it as its target to study the efficient microbial membrane with the marine yeast to be applied in BOD sensor for the in-shore seawater fishery.As is seen,biochemical oxygen demand（BOD） is one of the most important and widely used parameters for characterizing the organic pollution of water and sewage in the measurement of biodegradable organic compounds and pollutants of the ground surface and the seawater.To make clear the problem of the growth dynamics of the yeast strains known as the Debaryomyces hansenii,Pichia guilliermondii and Candida parapsilosis in the liquid glucose-peptone medium,we have done experiments and tests on their bio-characteristic features and gained the following results.To be accurate,we have discovered the highest oxidative activity against GGA in the late exponential or early linear growth phase.The developed laboratory-scale models of biosensors for BOD5 detection are based on the receptor elements with the yeast cells of Debaryomyces hansenii,Pichia guilliermondii and Candida parapsilosis.As is found,the biosensor Debaryomyces hansenii based is featured by the highest sensitivity,with the minimal limit of the linear range,accordingly.It is for this feature that we are sure that it is characteristically the best strain among all those we were experimented with.In addition,we have investigated the effects of pH,temperature and the concentration buffers by using the Response Surface Methodology（RSM）,while having done a test of the 33 factors we have developed to optimize the testing conditions.The results gained from the above experiments have shown that the optimal conditions should be chosen as follows： the pH value： 7.7;the temperature to be chosen： 20 ℃,the concentration buffers： 40 mmol/L,and the minimally relative error： 1% between the biosensor and BOD5.This optimal strategy is surely to lead to a decrease of the relative deviation from 4% to 0.5%.The above results indicate that it would be possible to use the Debaryomyces hansenii based biosensor as a reliable method for determining BOD in the seawater.What is more,the linearity range prove to be 9.3-422 mg/dm3 in case the glucose/glutamate BOD standard were applied.Such a newly discovered device will be able to provide a low-cost,easy-operated,fast-response,sensitive and reliable method to measure BOD in the seawater.It is also suitable for the on-line measurements.