Luminescent enzymatic flow sensor for d- and l-lactate assay in beer

Abstract

A bioluminescent flow sensor, previously developed for the determination of both D-and L-lactate in clinical samples, was utilized to carry out the same assay in beer. The sensor monitored the reduced form of nicotinamide adenine dinucleotide, produced by nylon-immobilized D-and L-lactate dehydrogenase, by means of bacterial bioluminescent enzymes immobilized on a separate nylon coil. The preparation of beer samples was very simple as only a modification of pH and a dilution were necessary. The recoveries ranged from 91% to 104%, and the relative standard deviations at the 1 mmol 1 -1 level were 4.6% and 6.7% for Land D-lactate respectively. The response was linear in the range 0.1-10 mmol 1 -1 for both D-and L-lactate. The total amount of lactate determined by bioluminescent biosensor (x) and by HPLC (y) showed a very good correlation (yp0.654 xc88.1, np29, rp0.918). The flow injection system developed allowed the determination of not only the total but also the individual contents of D-and L-lactate in beer, and the timely discovery of the unwanted presence of lactic acid bacteria.

Online Enzyme Discrimination and Determination of Substrate Enantiomers Based on Electrophoretically Mediated Microanalysis

“…In addition, there are still some difficulties to apply enzymes for chiral analysis, for example, cross-reaction with endogenous compounds, large sample and enzymatic reagent consumptions, and long reaction time to complete the enzymatic reaction . To overcome some of the shortcomings of off-line enzymatic assays, several flow injection analysis systems with two different enzymatic reaction columns or enzyme immobilized biosensors , for online enzymatic assays were proposed. Those methods require not only an efficient procedure of enzyme immobilization but also a complicated apparatus.…”

Optically Specific Detection of D- and L-Lactic Acids by a Flow-Injection Dual Biosensor System with On-line Microdialysis Sampling

“…Most of the enzyme sensors proposed are based on the amperometric [9][10][11][12][13] and chemiluminometric 14 detections of hydrogen peroxide or NADH produced by the lactate oxidase or lactate dehydrogenases (LDH) as a recognition element. A new method 15 that used natural animal tissue porcine kidney as a recognition element is also proposed for the chemiluminescence sensing of L-lactic acid.…”

“…A new method 15 that used natural animal tissue porcine kidney as a recognition element is also proposed for the chemiluminescence sensing of L-lactic acid. However, the development of biosensors which may enable the simultaneous determination of L-and D-isomers of lactic acid had not been achieved except for the successive detection 14,16 of the two isomers. In this note, a dual enzyme electrode suitable for the simultaneous amperometric detection of D-lactic and L-lactic acids is described.…”