Measurement of Escherichia coli concentration in lake water with electrochemical voltammetry using p-APG hydrolysis by endogenous beta-galactosidase
碩士 === 國立中興大學 === 機械工程學系所 === 106 === Current quantification of Escherichia coli in the water usually involves precise lab equipment which takes more than 24 hours after sampling. This paper reports a portable electrochemical detection method for Escherichia coli (E. coli) without the use of DNA amp...
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| Format: | Others |
| Language: | zh-TW |
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2018
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| Online Access: | http://ndltd.ncl.edu.tw/handle/kkbm84 |
| Summary: | 碩士 === 國立中興大學 === 機械工程學系所 === 106 === Current quantification of Escherichia coli in the water usually involves precise lab equipment which takes more than 24 hours after sampling. This paper reports a portable electrochemical detection method for Escherichia coli (E. coli) without the use of DNA amplification or immunoassays. The enzymeβ-galactosidase (β-gal) endogenous is a specific marker for E. coli. The β-gal endogenous enzyme will catalyzes the hydrolysis of p-aminophenyl-β-D-galactopyranoside (p-APG). The β-gal expression level is increased by treatment with a β-gal expression-inducer (isopropyl-β-d-thiogalactopyranoside, IPTG) and the hydrolysis reaction of p-APG is facilitated by the permeabilization treatment involving the use of sodium dodecyl sulfate (SDS). The detection principle was measured the β-gal expression level by electrochemical voltammetry method.
The calibration curve for E. coli from 101~105 colony-forming units (cfu)/ml in nutrient broth buffer (NB), stream water and lake water in National Chung Hsing University (NCHU) campus were measured. The linear regression equation for E. coli in NB is y = -0.022ln(x) + 1.016 with an R2 value of 0.958. The linear regression equation for E. coli in lake water in NCHU is y = -0.015ln(x) + 1.0133 with an R2 value of 0.948. The linear regression equation for E. coli in stream water in NCHU is y = -0.014ln(x) + 1.0113 with an R2 value of 0.953. The total detection time with sampling was less than 90 minutes. Experimental results showed that the portable electrochemical sensor can perform simple and sensitive detections to E. coli in stream water and lake water.
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